MR880 Technical Manual Rev A Sept 2004

Page 1

H

MR880 HUMIDIFIER

Technical Manual

REVISION A

September 2004

Copyright ©2004 Fisher & Paykel Healthcare Ltd.

Auckland, New Zealand

Page 2

Fisher & Paykel Healthcare

France/Benelux:

Head Office:

Parc Silic-Bal F,

PO Box 14-348, Panmure,

10 Avenue de Quebec,

Auckland 1134

Silic 512 Villebon, 91946,

New Zealand

Courtaboeuf, Cedex, France.

Email: info@fphcare.com

Tel: +33–(0)1-6446-5201

Web Site: www.fphcare.com

Fax: +33–(0)1-6446-5221

Tel: +64-(0)9-574-0100

Fax: +64-(0)9-574-0158

Australia:

USA:

36-40 New Street,

Suite 101 22982 Alcalde Drive,

Ringwood, Victoria 3134,

Laguna Hills, California 92653, USA

Australia,

Tel: +1-(949)-470-3900

Tel: +61-(0)3-9879-5022

Fax: +1-(949)-470-3933

Fax: +61-(0)3-9879-5232

Toll Free: (800)-446-3908

Germany:

UK and Ireland

Hundsbergerstrasse 45

(European Authorised Representative):

73642 Welzheim

Unit 16, Cordwallis Park

Germany

Clivemont Road, Maidenhead, SL6 7BU,

Tel: +49-(0)7182-93777-0

United Kingdom

Fax: +49-(0)7182-93777-99

Tel: +44-(0)1628626 136

Fax: +44-(0)1628626 146

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-2-

Page 3

Revision

Description of Technical Manual Change

Date Issued

A

First release of Technical manual

23/09/2004

Note:

1. Fisher & Paykel Healthcare have a policy of continued product improvement and reserve the

right to change specifications without notice.

2. This technical manual covers software version 2.22, 2.23, 3.01 and PCB revision D and E.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-3-

Page 5

1 Introduction

1.1 About this Manual

This manual is intended for qualified service personnel who will perform maintenance

and servicing on the Fisher & Paykel Healthcare MR880 Humidifier. This manual covers

the product specifications, includes a maintenance schedule, and provides the

necessary information required for servicing.

Maintenance procedures should be carried out at regular intervals (as recommended in

the maintenance schedule), to ensure that the humidifier and its accessories are working

correctly.

If a fault should occur with the humidifier, follow the troubleshooting guide (section 6) in

order to find the most likely cause. If the unit requires servicing, make sure the servicing

procedures are followed in order to prevent damage to the humidifier. After service, or as

part of the maintenance schedule, a humidifier performance check should be completed.

Due to the nature of the electronics contained within this humidifier, it is not

recommended that the printed circuit boards are serviced at a component level. Instead,

if the PCBs are found to be malfunctioning, they should be replaced.

1.2 Glossary

4-in-1 Probe

External probe consisting of four components: ambient

temperature sensor, chamber temperature sensor, flow

sensor, and heater wire adaptor.

Chamber

Device that in which the gas is heated and humidified, by

passing it over heated water.

Chamber Probe

Part of the 4-in-1 probe, this sensor assembly is used for

measuring the Probe

temperature and flow of the gas

travelling through the heated tube.

Chamber Set Point

The temperature that the humidifier attempts to maintain at the

chamber probe port.

Heated Tube

Tubing used to transport the gas to the patient.

Heater Wire

Coiled wire inside the heated tube used to heat the gas.

Heater Wire Adaptor

Part of the 4-in-1 probe, this electrical adaptor provides power

from the humidifier to the heated tube.

PCB

Printed Circuit Board.

Thermistor

A temperature sensitive resistor placed inside the chamber

probe.

1.3 Definitions

NOTE: A NOTE provides important information or explanation of procedures or

conditions which may otherwise be misinterpreted or overlooked.

CAUTION: A CAUTION statement designates the possibility of damage to this or other

equipment if a procedure is not followed exactly.

WARNING: A WARNING statement refers to conditions with a possibility of personal

injury if a procedure is not followed exactly.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-5-

Page 6

1.4 Product Application

The MR880 is a heated humidifier designed for use in respiratory humidification. It is

used to provide optimum humidity to gases delivered to patients.

Refer to the Product Guide or your local Fisher & Paykel Healthcare representative for a

list of approved accessories.

WARNING:

The use of heated tubes, chambers or other accessories which are not approved

by Fisher & Paykel Healthcare may impair performance or compromise safety.

Ensure maintenance of grounding integrity by connection to a "hospital grade"

receptacle.

Always disconnect supply before servicing.

Ensure that the chamber probe is correctly and securely fitted. Failure to do so

may result in temperatures in excess of 43°C being delivered to the patient.

Do not touch the glass tip of the chamber temperature probe during use. Keep

black connectors dry at all times.

Visually inspect accessories for damage before use.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-6-

Page 7

2 Humidifier Symbols

2.1 General Symbols

Type BF

Attention - consult accompanying documents

Caution: Electrostatically Sensitive Device

Alternating Current

Caution - Hot surfaces may exceed 85°C

Equipotential Stud

Drip proof protection to IPX1

C-tick for EMC

2.2 Humidifier Specific Symbols

Mute

Pressing this button turns the humidifier on or off (stand-by)

Humidity Alarm

Serial Port

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-7-

Page 8

3 Specifications

3.1 Mechanical

Dimensions:

Weight:

140 mm x 173 x 135 (without chamber fitted)

2.54 kg (without chamber fitted)

Approx. 2.62 kg (with chamber fitted, and filled with water)

3.2 Electrical

MR880 Model Number

Supply Voltage

Supply Current

MR880Axx

230 V~

1.0 A Max

Supply Frequency:

Heater Plate Capacity:

Heater Wire:

Heater Plate Thermal Cutout:

50 Hz

150 W at nominal mains voltage

22 ± 5 V ~, 2.7A Max, 60 W Max, 50 Hz

118 ± 6ºC

3.3 Temperature Range

During normal operation:

Display:

Chamber set point: 37 ºC,

(Can be 30 °C in low flow/ambient conditions)

Three digit, 14 mm, 7 segment LED

Range: 10 to 70 ºC

Accuracy: ± 0.3 ºC (in 25 to 45 ºC temperature range)

3.4 Alarm Parameters:

High Temperature Alarm:

Low Temperature Alarm:

Sound Pressure Level:

Causes an immediate visual alarm at a chamber

temperature of 41 °C (see sect. 4.3).

After 10 minutes @ 29.5 ºC causes an audible alarm.

After 60 minutes @ 35 ºC causes an audible alarm (see

sect 4.5)

NOTE: The humidity indicator will be lit when the chamber

temperature is below 35 °C, to indicate that the interface

may not be comfortable to wear.

Alarms exceed 50 dBA @1 m.

3.5 Performance

Recommended ambient temperature range:

18 to 30 ºC

Flow Range:

5 – 50 LPM

Humidity Performance:

>33 mg/L

Warm-up time:

Less than 15 minutes.

CAUTION: If operating outside the recommended temperature range, consult your

local Fisher & Paykel Healthcare representative.

3.6 Transport and Storage Environmental Conditions

Transport and Storage Conditions:

-10 to +50 °C

3.7 Standards and Approvals

IEC60601-1, IEC60601-1-2, ISO8185

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-8-

Page 9

4 Operating Modes and Controls

4.1 Humidifier Operation

The MR880 humidification system is designed to add heat and moisture to respiratory

gases. The system is used to deliver humidified air/oxygen mixes to patients requiring

respiratory humidification. The gas is passed through a humidification chamber where it

is warmed and humidified. The humidity in the gas is then maintained as it travels along

the heated tube to the patient.

The MR880 has two heating systems. The first is a heater plate, which heats the water

contained in the humidification chamber. Gas passing through the chamber is warmed

and humidified. The humidifier monitors the temperature of the gas at the chamber

outlet using the chamber probe, and controls the amount of power delivered to the

heater plate in order to maintain the chamber set point.

The second heating system is the heater wire encapsulated within the heated tube.

Humidified gas from the chamber travels through the heated tube and then the unheated

section to the patient interface, where its temperature must be maintained in order to

prevent the generated humidity from condensing. The humidifier monitors the gas flow

rate using the chamber probe and the ambient room temperature using the ambient

sensor so the gases at the patient interface contain the same heat and humidity as at the

chamber. See Figure 4.1 below for the set-up of the humidifier.

Figure 4.1 MR880 Humidifier Set up

4.1.1 Power Up Sequence

The purpose of the power up sequence is to perform internal checks on various parts of

the humidifier and provide the user with a visual and audible check.

Internal self test sequence:

1.

Test integrity of 4-in-1 probe.

2.

Test correct operation of heater wire triac.

3.

Test correct operation of protection relays.

Visual/Audio test sequence:

1.

All 7-segment display and indicator LEDs turned on.

2.

The 7-segment display is blanked and indicators set to their default.

3.

Display shows humidifier model number eg. 880.

4.

Display shows software version number with no decimal point e.g. 223.

5.

Display is blanked.

6.

Normal display (chamber temperature).

After power-on the humidifier starts an internal diagnostic routine which checks for

possible problems in the humidifier setup. If everything is working correctly, normal

control is initiated.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

-9-

Page 10

4.1.2 Fault Handling

If the humidifier detects a problem with its setup or operation it will alarm. Depending on

the severity of the alarm condition, the humidifier will either reduce or remove power

from the heating systems described above in section 4.1. For further detail on operation

under different alarm conditions see section 4.5.

The humidifier will also enter stand-by if the gas flow through the circuit is measured

below 3 LPM. In stand-by the following occurs:

• Heater wire power is set at 30%.

• Heater plate temperature is limited to 50°C.

• Heater plate power is limited to 20%.

4.2 Humidifier Controls

4.2.1 Power Button

The humidifier will power on if this button is held down briefly, but must be held for one

second to turn the humidifier off. Note that although the display is not illuminated, the

unit may still be energized. Be sure to disconnect power to the MR880 before

servicing.

4.2.2 Mute Button

The mute button silences the humidifier's audible alarm. The muted time depends on the

alarm condition. In general, alarms will be muted for 2 minutes. The chamber probe

alarm is muted for a longer time, until the humidifier determines whether the probe is in

or out. The low humidity alarm is treated differently - see section 4.5.

4.3 Temperature Display

The front panel shows the chamber temperature during normal operation. This

temperature gives an indication of the dew point (in °C) of the gas that is being supplied

to the patient. The dew point of a gas is the best indication of both its humidity and

energy content. If the temperature is above 70°C, "Hi" will be displayed. If the

temperature is below 10°C, "Lo" will be displayed.

4.3.1 Ambient Temperature and Flow Rate Display

Both the ambient temperature and flow rate can be displayed by pressing the mute

button for 3 seconds during normal operation. The readings are displayed in the

following sequence, with an audible beep between each change of display:

•

Display the ambient sensor reading in °C, and also light the ambient sensor LED to

indicate which reading is being displayed.

•

Display the flow reading in LPM, and also light the chamber probe LED, to indicate

which sensor reading is being displayed.

•

Return to normal operation display.

Each display is held for 2 seconds, or until 2 seconds after the mute button is released,

whichever is longer.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 10 -

Page 11

4.4 Setup Indicators

The MR880 setup indicators, placed on the lower left of the front panel, are intended to

aid the user in identifying problems with the incorrect setup of the device and its

accessories.

4.4.1 Heater Wire Connector and Chamber Probe:

Lights if the heater wire in the heated tube has not been connected correctly, or if

the heater wire or 4-in-1’s heater wire adaptor is faulty. The humidifier will shut

down the heater wire and heater plate if this alarm is active.

This indicator is also used if the chamber probe not inserted into the heated tube

correctly. In this case the temperature display will also flash ‘---‘ to indicate that

there is no accurate chamber temperature available. On start-up, and during

rapid changes in temperature, the humidifier tests if a probe is in place by cooling

and then heating the chamber. If the humidifier finds that the probe is not inserted

into the heated tube, an alarm will be generated and the humidifier will enter

stand-by. During this alarm the humidifier will initiate a retest if a rise in

temperature is detected or after 15 minutes has elapsed.

4.4.2 4-in-1 Probe Connector:

This indicator will light if the chamber probe is not correctly plugged in, or the

probe used is faulty. The humidifier tests for the following probe fault conditions:

• 4-in-1 probe disconnected

• Chamber thermistor open or short circuited

• Flow thermistor open or short circuit (shorted probe test)

• Ambient thermistor open or short circuited

• One thermistor shorted to another (shorted probe test)

• Flow calibration resistor open or short circuit (shorted probe test)

An alarm will be generated if any of the above faults are found, and the humidifier

will shut down the heater wire and heater plate if this alarm is active.

NOTE: the shorted probe tests are only performed on start-up, or when

temperature probe or heater wire alarms are cancelled.

4.4.3 Water Out Indicator:

This indicates that there is insufficient water in the humidification.

The humidifier measures the amount of power used to obtain the chamber

temperature. If a lower than expected amount of power is used, a 'water out'

alarm is generated. It may take 20 minutes to generate an alarm especially if

there is a disturbance (change in flow).

This alarm can be cancelled by pressing the mute button. If however the water

out condition remains, the humidifier will re-alarm as described above.

4.4.4 Ambient Temperature Indicator

This indicates that the ambient temperature is being displayed on the front panel.

It is only used when the ambient temperature and flow rate display sequence is

initiated by the user (refer section 4.3.1).

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 11 -

Page 12

4.5 Operational Alarms

These alarms are generated if problems occur with the operation of the humidifier.

4.5.1 Humidity Indicator:

The humidity indicator is used to indicate high and low humidity present at exit of

chamber.

High Humidity Alarm:

The temperature display and patient light will flash if at any time the chamber

temperature exceeds 41°C. If this alarm occurs, the humidifier will immediately

shut down the heater wire and heater plate, ensuring energy delivered to the

patient cannot cause any energy risk.

Low Humidity Warning:

It is used to indicate that the system has not warmed up to the ideal temperature

for user comfort. The patient interface should be used once this indicator is

turned off.

Low Humidity Alarm:

The low humidity alarm indicates that a low level of humidity has been delivered

to the patient for a period of time. If the chamber temperature remains low for too

long, then a visual and audible alarm is activated. The time taken for the

humidifier to alarm is dependent on how far the chamber temperature is below

the 35°C threshold. Figure 4.2 shows the relationship between temperature, a

humidity warning and the time before a humidity alarm:

Figure 4.2 Temperature versus Time to Alarm

Pressing mute during a low humidity alarm silences the alarm for half the normal

time period, if the same temperature is maintained.

The low humidity warning and alarm can be triggered by cold or breezy ambient

conditions, or can result from using gas flow rates outside the specification of the

heated tubing, chamber or humidifier.

4.5.2 See Manual Indicator:

This indicates a serious hardware fault. Please refer to section 6

"Troubleshooting".

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 12 -

Page 13

5 Maintenance Procedures

In order to keep your humidifier in good working order it is necessary to perform

maintenance at regular intervals. The maintenance schedule below is designed to

ensure testing is carried out on different heaterbase functionality in an appropriate time

frame.

5.1 Maintenance Schedule

5.1.1 MR880 Humidifier

Annually

a. Check MR880 for physical damage:

• Check the mains cable for damage, replace if necessary.

• Check the heater plate for deep scratching etc., replace if necessary.

b. Carry out a full performance test. This procedure is detailed in section 8.

NOTE: A maintenance check sheet is given in Appendix A.

5.1.2 4-in-1 Probe

Every Six months

a. Visually check the humidifier probes for physical damage:

• Check that the chamber probe's glass thermistor has not been damaged.

Replace probe if required.

• Inspect the chamber probe's glass thermistor for deposits or foreign material.

Clean probe as required.

• Check the probe cable for kinks and abrasions and damaged connectors.

• Check that the probe connectors couple with the humidifier sockets.

b. The probe accuracy and the accuracy of measuring circuits within the humidifier need

to be checked:

• Carry out a temperature accuracy test on both ambient and chamber temperature

probes.

• A flow accuracy check should be performed on the 4-in-1 probe and MR880.

These tests are outlined in section 8.2.

5.2 Safety Check

The unit should be tested to the current medical electrical standards for in-house testing

for each specific country (example, refer to AS/NZS 3551 for Australia and New

Zealand).

CAUTION: Permanent damage to this humidifier will result if the serial port is used as a

ground point during electrical safety testing. The correct ground point location is the

heater plate.

Figure 5.1 Location of ground test point on the heater plate

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 13 -

Page 14

5.3 Cleaning Instructions

5.3.1 MR880 Humidifiers

It is recommended that only the following cleaners be used on the MR880 as at the time

of revision of this technical manual. The disinfectants in the list below have been tested

to ensure that no damage will result to the outer plastic or metal components of the

humidifier.

Cleaning instructions

1.

2.

3.

Disconnect the humidifier from any electrical outlet.

Clean the humidifier with one of the following using a damp cloth:

Isopropyl Alcohol

Normal dishwashing detergent

DO NOT immerse the humidifier in any liquid.

Wipe the humidifier clear of any cleaning residues before use.

5.3.2 The 4-in-1’s Chamber Probe

The cleaning methods listed below meet the FDA regulations for these types of devices,

and do not affect the integrity or performance of the probe. It is the user’s responsibility

to qualify any deviations from these procedures, both for disinfecting efficacy and

physical effect on the probe. For advice on other cleaning methods not mentioned here,

contact your local Fisher and Paykel distributor.

Cleaning instructions

NOTE: Refer also to the disinfection instructions on the instruction sheet for the 4-in-1

Probe,

Ref 185042788.

1.

2.

Physically clean the probe, removing all visible contaminants.

Disinfect the probe with one of the following solutions:

Sporicidin; Sporox; Cidex; Cidex  OPA

OR

Sterilise the probe using Ethylene Oxide sterilisation at 55°C (131°F), 80kPa.

(Allow at least 15 hours for residual ETO to disperse before use).

NOTE:

Follow the manufacturer’s instructions carefully.

Use the correct dilution of the disinfectant.

CAUTION: DO NOT immerse the black electrical connector plug in disinfectant.

DO NOT autoclave probes.

DO NOT use dishwater detergents or solvents.

3. Wipe the chamber probe clear of any cleaning residues before use.

4. Store in clean conditions.

Cidex

 is a registered trademark of Johnson & Johnson Medical Pty. Ltd. North Ryde, NSW,

Australia.

Sporicidin

 is a registered trademark of Sporicidin International Ltd, Rockville, MD 20852,

USA.

Sporox

 is a registered trademark of Reckitt & Colman Inc. 1655 Valley Rd. Wayne NJ USA

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 14 -

Page 15

6 Troubleshooting

6.1 Operational Problems

This section deals with faults that cause the humidifier to alarm. This may be caused by

incorrect setup, faulty accessories, or a faulty humidifier.

Symptom

Corrective Action

Reference

See manual

indicator flashing

with audible alarm

Record the displayed error code. Refer to section 6.3.

Section 6.3

See manual

indicator light

permanently on,

without an audible

alarm

1. If “PTS” is displayed on the front panel, then the production

test button is on. Ensure that the production test button is

not depressed. Replace the humidifier PCBs if the problem

persists.

Section 7.3.5

(see step 5)

2. There has been a microprocessor failure. Replace PCB’s

Section 6.2

Water Out indicator

flashes,

accompanied by an

audible alarm

1. Check that there is sufficient water in the chamber. Refill

or replace chamber as necessary.

2. Check that the gas flow rate is within specification of the

humidifier and accessories being used. Adjust as

necessary.

MR880

Instructions

3. Condensate formed on chamber probe? Dry the probe

and re-test.

4. 4-in-1 probe faulty. Complete a temperature and flow

accuracy check on the probe. Replace probe as required.

5. Humidifier faulty. Complete a performance test. Service

humidifier as required.

Section 8.2

Section 8.1

Chamber probe

alarm flashes

accompanied by an

audible alarm,

normal

temperature

display

1. Check that the heater wire is correctly plugged into the

humidifier and the heated tube.

4. Humidifier faulty. Replace PCBs.

Section 7.3.2

Chamber probe

alarm flashes

accompanied by an

audible alarm and

flashing

temperature

display

1. Check that the chamber probe is inserted into the heated

tube correctly, and that the heated tube is set up correctly.

Accessory

instructions

2. Replace heated tube, and re-test.

3. Replace 4-in-1 probe, and check for intermittent

connections. Re-test.

2. Check that there is sufficient water in the chamber. Refill

as necessary.

3. Ensure correct chamber is being used.

4. Check that the gas flow rate is within specification of the

humidifier and accessories being used. Adjust as

necessary.

MR880

Instructions

5. Has condensate formed on the chamber probe? Dry

probe and re-insert.

6. 4-in-1 probe or humidifier faulty. Complete performance

tests. Replace probe or service humidifier as required.

4-in-1 probe

connector indicator

flashes,

accompanied by an

audible alarm

Section 8

1. Is the probe connector correctly plugged into the

humidifier? Plug in probe as required.

2. Perform a humidifier calibration check.

Section 8.1.1

3. Replace 4-in-1 probe and re-test. If the alarm condition

disappears, the 4-in-1 probe is faulty. Discard faulty

probe.

Section 7.3.2

4. Humidifier faulty. Replace PCBs.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 15 -

Page 16

Humidity indicator

is constantly lit

The humidifier is still warming up to optimal temperature. The

system will be comfortable to use when the indicator is not lit.

Symptom

Corrective Action

Humidity Indicator

flashes, with

audible alarm,

coupled with a low

temperature

(<35°C) displayed

The humidifier has been unable to maintain temperature over a

period of time.

1. Check that the gas flow rate is within specification of the

humidifier, and accessories being used.

Reference

MR880

Instructions

2. Check for drafts around the heated tube. This can be

caused by fans or room air conditioning. If this is found to

be the cause, the heated tube should be removed from the

path of draft. Do not cover heated tube by any means.

3. Humidifier or probe faulty. Complete humidifier & probe

performance test. Replace probe or service humidifier as

required.

Section 8

WARNING: Never cover the heated tube or place

in the path of radiant heat.

Humidity indicator

flashes and a high

temperature is

displayed

1. Has the gas flow rate been changed? Monitor the

displayed temperature for several minutes for a drop in

temperature.

2. If the temperature does not begin to fall then remove

humidifier from patient, and complete a performance test

on the humidifier, and 4-in-1 probe. Replace probe or

service humidifier as required.

Section 8

6.2 Technical Problems

Problems that cause the humidifier to malfunction without an audible alarm are

discussed in this section.

Symptom

Corrective Action

See manual

indicator lit (not

flashing)

1. Check that the mains supply is within specification.

Provide adequate mains supply if required.

Humidifier will not

turn on with on/off

button, and no

indicators are lit

Reference

2. If ‘PtS’ is displayed, refer to section 6.1.

Section 6.1

3. Replace PCBs.

Section 7.3.2

1. Humidifier plugged into mains supply?

2. Check that the mains supply is within specification.

Provide adequate mains supply if required.

3. Remove mains power and check the fuses.

Section 7.3.1

4. Check continuity of mains power cord. Replace as

necessary.

Section 7.3.6

5. Check the transformer windings are not open circuit.

Primary Winding: Red wires

Secondary 10v winding: White wires

Section 7.3.3

Secondary 22v winding: Yellow wires

If any windings are open circuit, replace the transformer.

6. Replace PCBs.

Section 7.3.2

Unit fails

calibration check

Send unit to a Fisher & Paykel Healthcare service

representative for calibration, or replace PCBs.

Section 7.3.2

4-in-1 Probe fails

probe accuracy

check

Replace probe.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 16 -

Page 17

Unit fails to reach

temperature in

heater control

check. (Section

8.1.4)

1. If the chamber outlet temperature was low, the heater plate

element should be checked. Replace element as

necessary.

Section 7.3.4

2. Replace PCBs.

Section 7.3.2

6.3 “See Manual” Error Codes

The following is an explanation of the error codes that are displayed in conjunction with

the See Manual indicator flashing. A code is not displayed if the microprocessor has

stopped functioning (see technical problems - section 6.2).

Error Description of Fault

E00

E02

E03

E04

E05

E06

E07

E10

E11

E12

E13

E14

E15

E16

E20

E21

E22

E23

E25

E26

E27

E28

E29

E2A

E2C

E2D

E30

E31

E40

E41

E42

E43

E44

E45

E4A

E4B

E4C

E50

E51

No fault

Microprocessor stack overflow

RAM fault

ROM fault

EEPROM version older than ROM version. Update EEPROM. Refer to Section 7.3.5

EEPROM version newer than ROM version – (old software). Contact Fisher & Paykel

Healthcare

Incorrect ROM type used (wrong model)

Temperature circuit calibration out of range: Range Amp 0: 25.5°C

Temperature circuit calibration out of range: Range Amp 0: 65.0°C

Temperature circuit calibration out of range: Range Amp 1: 25.5°C

Temperature circuit calibration out of range: Range Amp 1: 34.5°C

Temperature circuit calibration out of range: Range Amp 2: 34.5°C

Temperature circuit calibration out of range: Range Amp 2: 44.6°C

Temperature circuit calibration out of range: Range Amp 3: 60.0°C

Heater wire circuit is not functioning:

- Heater plate thermal cutout tripped (section 7.3.4)

- Heater wire fuse (F2) is open circuit (section 7.3.1)

- Heater wire triac drive, or heater wire relay is open circuit

Heater wire triac is short circuit

Incompatible circuit type – software upgrade needed to use in mask mode

Triac circuit sense fault

Transistor Q17 is not turning on

Transistor Q16 is not turning on

The heater wire relay is short circuited

Mains voltage measurement is uncalibrated (section 8.1.3)

The heater plate thermistor is short circuit

The heater plate thermistor is open circuit

Heater plate element is not turning on:

- Element is open circuit, or

- Heater pate triac/triac driver faulty or

- Heater plate relay is faulty

The heater plate element is not turning off. Heater plate triac circuit faulty.

Power (on/off) button stuck on

Mute button stuck on

Unit not functional tested at time of manufacture

Failed the functional test at time of manufacture

Was not stress tested during manufacture

Failed the stress test during manufacture

Not tested on functional tester 2

Failed production functional tester 2

EEPROM write error occurred

EEPROM write verify error occurred

EEPROM read error occurred

Flow circuit open fault

Flow shorted fault

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 17 -

Page 18

7 Servicing Procedures

7.1 General Considerations

WARNING: Although the MR880 display may not be illuminated, the unit may still

be energized. Be sure to disconnect the MR880 from the power supply before

servicing.

All servicing procedures should be followed by a humidifier performance test, and

an electrical safety test to ensure proper operation. The performance tests are

outlined in section 8.

CAUTION: Where screws and bolts have been removed from the product, do not use

excessive force when re-fastening.

Antistatic procedures should be followed when servicing this product.

7.2 Disassembly

7.2.1 Opening the case

1.

2.

3.

Ensure mains power is disconnected from the unit.

Remove the four screws at the back of the humidifier.

Remove front half of case by sliding the two halves apart. Pull the front half of the

case away from the rear. See figure 7.1.

Figure 7.1. Showing two halves of case being slid apart.

4.

The control PCB is attached to the front half of the case. The PCB in the rear half

of the case is the power PCB.

Slide the power PCB forward with the side panel (the side panel is attached to

the power PCB). The side panel will need to be pushed inwards during the sliding

action in order to unlatch and clear the electrical connector.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 18 -

Page 19

5.

Un-clip the three fasteners (figure 7.2) which hold the front (control) PCB to the

front of the case, and separate the front PCB from the case.

Figure 7.2 Showing PCB fasteners.

7.2.2 Closing the case

1.

2.

3.

4.

5.

Make sure that all harnesses that were previously disconnected have been

reconnected. If the mains wiring was disconnected during servicing, check that

the mains polarity is correct (see table on previous page).

Slide the power PCB back into position, ensuring that the side panel slides in the

slots and latches into the case rear.

Place the control PCB back into position in the front of the case, ensuring all clips

are located properly.

Slide the case together, and replace the four screws.

In order to check that the humidifier is working properly, complete a full

performance test as outlined in section 8.

7.3 Servicing

7.3.1

Replacing Fuses

1.

2.

Open the case (see 7.2.1).

The fuses can now be accessed. See figure 7.3 for the location of the fuses on

the power PCB.

F4 F3

F1

F2

Figure 7.3 Showing location of the fuses on power PCB.

The four fuses have the following ratings and its part numbers:

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 19 -

Page 20

MR880 Model Number

MR880AEA

Supply Voltage

230V ~

Fuse Type

F1: 1A 250V FastBlow

F2: 4A 125V FastBlow

F3: 2A 250V FastBlow

F4: 2A 250V FastBlow

Part Number

999 830 001

999 830 017

999 830 009

999 830 009

WARNING:

Be sure to replace the fuse with the correct rating and type. Do not under any

circumstances replace F2 with anything other than a fast blow fuse of the type and

rating specified, as serious injury could result.

3.

4.

Replace fuse.

Close the case (section 7.2.2).

7.3.2 Replacement of Printed Circuit Boards (PCBs)

1.

2.

3.

4.

5.

6.

Open the case (see section 7.2.1).

Disconnect all harnesses attached to the power PCB. Disconnect the mains and

protective earth wires by unscrewing the terminal blocks and cutting the cable

ties (see figure 7.4).

Remove PCBs, and send for servicing. Note that the side panel (including the

connector) is replaced, along with the power PCB.

Unpack replacement PCBs, replace the mains fuses (F3, F4) with the correct

type, and attach mains and protective earth wires, using the cable ties provided.

See figure 7.4.

Connect harnesses from the transformer and heater plate to the power PCB.

Close the case (section 7.2.2).

Transformer

Primary

Thermal cutout &

thermistor

Heater plate

element

Transformer

Secondary

Mains cord

phase

Mains cord

neutral

Heater plate & mains cord earth

Figure 7.4 Showing Humidifier Power PCB wiring

7.3.3 Replacement of Transformer

1.

2.

3.

4.

5.

6.

Open the case (see section 7.2.1).

Disconnect the transformer primary and secondary harnesses attached to the

power PCB.

Unscrew the four mounting screws fixing the transformer, and remove the

transformer from the case.

Place the new transformer inside the case, and mount using the four screws.

Connect transformer primary and secondary harnesses to the power PCB.

Close the case (section 7.2.2).

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 20 -

Page 21

7.3.4 Servicing the Heater Plate

Resetting the thermal cutout.

1.

2.

Open the case (see section 7.2.1).

Check the thermal cutout on the heater plate by pushing the red button with a

pen or small screwdriver - see figure 7.5.

Figure 7.5 Showing location of thermal cutout.

3.

If the thermal cutout "clicks" when pushed, it has been previously activated, and

is now reset.

If the heater plate is still hot, it must be allowed to cool sufficiently

before the thermal cutout will reset.

Close the case (section 7.2.2).

NOTE:

4.

Replacing the heater plate thermistor

NOTE: A Heater plate thermistor service kit is required. (Part Number: 043 041 254)

1.

Open the case (see section 7.2.1).

2.

Disconnect the heater plate element, thermistor and thermal cutout harnesses

attached to the power PCB.

3.

Remove the three screws holding the heater plate - see figure 7.6.

Figure 7.6 Showing location of Heater Plate screws.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 21 -

Page 22

4.

5.

6.

Cut cable ties attached to the heater plate harnesses.

Remove screw holding heater plate thermistor - see figure 7.7.

Desolder the wires attached to the thermal cutout, and remove the old thermistor

and harness.

Thermal cutout

Thermistor

Figure 7.7 Location of heater plate thermistor,

thermal cutout and element screws.

7.

8.

9.

10.

11.

12.

Place the new thermistor into position, and attach using the screw.

Solder the wires from the new harness to the heater plate thermal cutout.

Attach the cable ties provided to the heater plate harness.

Place heater plate back into position, ensuring the springs underneath the heater

plate are in place. Attach to the humidifier's case using the three long screws that

were previously removed.

Connect the heater plate element, thermistor and thermal cutout harnesses to the

power PCB.

Close the case (section 7.2.2).

Checking the heater plate element

1.

2.

3.

Open the case (see section 7.2.1).

Disconnect the heater plate element, thermistor and thermal cutout harnesses

from the power PCB.

Measure the resistance between the 2 contacts on the heater plate element

connector (this is the large three pin connector).

The resistance of the heater plate element should measure the same as outlined

in the table below:

MR880 Model Number

MR880AEA

Supply Voltage

230V ~

Heater Plate Resistance

353 + 12 Ohms

If the measured resistance is outside this range, replace the heater plate element

(steps 4 to 9). If the heater plate element is within specification, go to step 10.

NOTE:

4.

If the heater plate element requires replacing, a heater plate element

service kit is required - see Appendix C: Heater Plate Assembly.

Remove the two visible screws holding the heater plate element reflector.

Remove the shield, making sure the washers are not lost. Unscrew the last four

screws on the element cover (see figure 7.7).

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 22 -

Page 23

5.

6.

7.

8.

9.

10.

11.

Remove the heater element, leaving the mica insulator in place.

Insert the new element into position, making sure the insulating mica is between

the element and the heater plate.

Replace the element cover, using the four screws that were previously removed.

Replace the element reflector, making sure the washers that separate the

reflector from the cover are placed back into position. Screw into place.

Place the heater plate assembly back into position, ensuring the springs

underneath the heater plate are in place. Attach to the humidifier case using the

three long screws that were previously removed.

Connect the heater plate element, thermistor and thermal cutout harnesses to the

power PCB.

Close the case (section 7.2.2).

Replacing the Thermal Cutout

Note: A thermal cutout service kit is required. (Part Number: 349 040 052)

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

Open the case (see section 7.2.1).

Disconnect the heater plate element, thermistor and thermal cutout harnesses

from the power PCB.

Remove the three screws holding the heater plate - see figure 7.7.

Desolder the two black wires attached to the thermal cutout.

Unscrew fasteners used to secure the thermal cutout, and remove.

Place new thermal cutout in position and fasten using screws provided.

Depress the thermal cutout's red button to ensure it is reset.

Solder the black wires that were previously disconnected to the contacts on the

new thermal cutout.

Place heater plate back into position, ensuring the springs underneath the heater

plate are in place. Attach to the humidifier's case using the three long screws that

were previously removed.

Connect the heater plate element, thermistor and thermal cutout harnesses to the

power PCB.

Close the case (section 7.2.2).

7.3.5 Installing New Software

1.

2.

Open the case (see section 7.2.1).

Remove ROM integrated circuit U3 (see figure 7.8) using appropriate tools.

Figure 7.8 Location of U3 ROM

3.

4.

5.

Place new ROM into the empty socket, ensuring correct orientation.

Close the case (section 7.2.2)

Turn the humidifier upside down; use a non conducting tool to hold the production

test button down. This button is accessible through the right air vent slot (when

looking at the rear of the humidifier). - See figure 7.9.

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 23 -

Page 24

WARNING: Never use an electrically conducting tool to depress the

production test button, as there are live mains voltages inside the

humidifier.

Figure 7.9 Showing Location of the Production Test Button.

5.

6.

7.

Apply mains power to the humidifier, while keeping the production test button

depressed. The display should read: “PTS”. This ensures that the new software

version number will be properly updated in the EEPROM.

Turn off the mains power to the humidifier, and remove the tool.

Check that the humidifier powers up normally, and complete a full performance

test (section 8).

7.3.6 Replacing the mains cable

1.

2.

Open the case (section 7.2.1).

Unscrew the three mains cable wires from the terminal blocks on the power PCB

(see figure 7.4), and cut the cable tie on the PCB.

3.

Slide the mains cable retainer away from the rear of the case.

4.

Replace the power cord, and affix to the case by forcefully pushing the retainer

back into position (towards the rear of the case).

Attach the 3 mains cable wires to the terminal blocks on the power PCB (see table below for

correct mains cable wiring), and attach the phase and neutral wires with a new cable tie.

CORD TYPE

NZ / AUSTRALIA

(230V)

PHASE

Brown

NEUTRAL

Blue

EARTH

Green / Yellow

WARNING: When attaching the mains cable wires, ensure that the correct

polarity of the mains wiring is followed. The table given above only applies

to power cords supplied by Fisher & Paykel Healthcare.

5.

Close the case (section 7.2.2).

7.4 Installing the equipotential stud

1.

2.

3.

4.

5.

6.

Open the case (section 7.2.1).

Create the stud hole by puncturing the perforation beneath the heater base shell (figure

7.10)

On the underside of the heater base, fit the green/yellow washer in place, followed by

the wavy washer, and followed by the stud.

On the inside, fit the remaining components over the equipotential stud in the following

sequence: Flat washer; ring terminal on the earth wire; star lock washer; M6 Nut.

Insert the crimped end of the earth wire into the spare hole on the earth bar of the

MR880 PCB, and tighten using brass screw supplied.

Close the case (section 7.2.2).

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 24 -

Page 25

Stud

Puncture the

stud hole

Green/yellow

washer

Stud

Ring

terminal of

earth wire

M6 Nut

Star lock

washer

Wavy

washer

Flat washer

Figure 7.10 Installing the stud components

8 Performance Testing

This section discusses the performance testing of the MR880 humidifier and also the

MR880’s 4-in-1 probe. Performance testing is required as part of ongoing maintenance

or after servicing of the humidifier has been completed.

8.1 Humidifier Performance Testing

If the humidifier has been operating normally, but a performance check is required as

part of the maintenance schedule, it is recommended that the following tests are

completed:

1.

2.

A humidifier Calibration Check (section 8.1.1)

A humidifier Display Check (section 8.1.2)

However, if there is a problem with the humidifier, or if the humidifier has recently been

serviced, then the following tests should be completed in addition to those outlined

above.

3.

4.

A humidifier Voltage Calibration Check (only required if the MR880's PCBs or

mains transformer have been serviced or replaced.) (Section 8.1.3)

A humidifier Warm-up and Control Check. (Section 8.1.4)

Entering the Service Menu

The MR880 humidifier has a special mode which enables the operator to verify correct

operation. To enter this mode, hold down the power button on the front of the humidifier

then apply mains power. The See-Manual indicator will light, and the humidifier will enter

the service menu. The service menu has six different tests:

MR880 Technical Manual * Ref. 185043483 (Internal 185043679) * Revision A * Issued September 2004

- 25 -