Rheem 55027500, 55127507 Service Instructions Manual
This document is stored and maintained electronically by Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
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SERVICE INSTRUCTIONS
Air Sourced Heat Pump
TM017
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550275
551275
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
1
Contents
Safety Warning....................................................................................................................2
Introduction..........................................................................................................................2
Specifications.......................................................................................................................3
Preventative Maintenance ...................................................................................................3
Operation.............................................................................................................................4
Refrigeration Terms and their Meaning................................................................................5
Components and their Function...........................................................................................5
Common Faults ...................................................................................................................6
Product Changes.................................................................................................................8
Wiring Diagrams..................................................................................................................8
Refrigeration Sealed System Diagrams.............................................................................10
Performance Graph...........................................................................................................11
Fault Finding......................................................................................................................12
550275 Power Supply Fault Finding - Chart 1...................................................................13
Thermostat Circuit Fault Finding - Chart 1.1......................................................................14
Refrigerant System Fault Finding - Chart 1.2.....................................................................18
Refrigerant System Fault Finding - Chart 1.3.....................................................................19
Refrigerant Charge ............................................................................................................20
Refrigerant System Fault Finding - Chart 1.4 & 2.2...........................................................21
Refrigerant System Fault Finding - Chart 2........................................................................22
De-ice Thermostat Fault Finding - Chart 2.3......................................................................24
Evaporator Thermostat Fault Finding - Chart 2.4...............................................................24
Insufficient Hot Water - Chart 3..........................................................................................25
Insufficient Hot Water - Chart 3.1.......................................................................................26
Leaking Water Heater - Chart 4.........................................................................................27
Noisy Water Heater - Chart 5.............................................................................................28
Electrical Insulation Test - Chart 6.....................................................................................29
Electrical Insulation Testing............................................................................................30
551275 Power Supply Fault Finding - Chart 7...................................................................31
551275 Booster Circuit Fault Finding - Chart 8..................................................................33
Component Replacement Procedures - Water Heater ......................................................36
Component Replacement Procedures - Refrigeration Plant..............................................38
Exploded View - Refrigeration Plant - 550 Series..............................................................46
Replacement Parts List..................................................................................................46
Exploded View - Refrigeration Plant - 551 Series..............................................................47
Replacement Parts List..................................................................................................47
Exploded View - Water Heater - 550 Series ......................................................................48
Replacement Parts List..................................................................................................48
Exploded View - Water Heater - 551 Series ......................................................................49
551 Series Replacement Parts List................................................................................50
Rheem Electric Water Heater Warranty - (Australia Only).................................................51
Document Revision History................................................................................................52
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
2
Safety Warning
The purpose of this Service Manual is to provide sufficient information to allow a person
with the skills as required by the controlling Regulatory Authorities to carry out effective
repairs to a Rheem Air Sourced Heat Pump Water Heater in the minimum of time.
Safety precautions or areas where extra care should be observed when conducting tests
outlined in this manual are indicated by print in bold italics and/or a warning symbol. Take
care to observe the recommended procedure.
Certain diagnostic procedures outlined in these service instructions require
“live” testing to be conducted. Personal Protective Equipment (PPE) should
be worn when conducting these tests to prevent the risk of electric shock.
(Refer to the Rheem Safety Procedure on electrical testing)
R22 and R409A are controlled substances under the fair trading act.
Personnel qualified and licensed to work with refrigerants may only carry
out service and repair to the sealed refrigeration system. During repair the
refrigerant must be recovered, not vented to atmosphere.
Environmental
At the end of the service life of a Rheem heat pump the refrigerant must be
recovered by personnel qualified and licensed to work with refrigerants
prior to the unit being disposed of. Refrigerants must not be vented to
atmosphere.
Introduction
The information provided in these instructions is based on the water heater being installed
in accordance with the Installation Instructions provided with each water heater.
Should you require further technical advice on a Rheem Air Sourced Heat Pump Water
Heater, contact your nearest Rheem Service Department where all genuine replacement
parts are also available.
Heater Model Identification
All identification numbers are designed to convey detailed information about the water
heater to which it is attached. The model number consists of 8 digits.
5 5 0 275 0 0
5 – Renewable Energy Model
5 – Air Sourced
9 – Solar Sourced
0 – No Heating Units
1 – Booster Element
Storage Capacity in Litres
No Reference – System Requirement
0 – Element Not fitted
5 – 2400 watts
7 – 3600 watts
Note: Model number, serial number and date of manufacture should be quoted in all
correspondence.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
3
Specifications
Water Heater
Model 55027500 55127507
Capacity - Litres 275 275
Boost Capacity - Litres 0 130
Booster element rating - kW Not fitted 2.4 or 3.6
T&PR valve Rating - kPa 1000 1000
With ECV 680 680
Maximum inlet pressure - kPa
Without ECV 800 800
Inlet / Outlet RP¾/20 RP¾/20
Water Connections
T&PR RP½/15 RP½/15
Quantity 2 2
Anode
Length 1153 1153
Compressor t/stat setting (fixed) - ºC 49ºC* 55ºC*
Booster thermostat setting (trade adjustable) - ºC Not fitted 60ºC
Booster ECO setting - ºC N/A 85ºC
*Delivered water temperature 65-75ºC
Refrigeration System
Parameter 55027500 55127507
Superheat setting (Factory) +3ºC at 10ºC Evaporator temp.
Compressor ECO setting 105ºC, manual reset
R22 1350 grams
Refrigerant charge
R409A 1250 grams
Bypass solenoid coil resistance 2 kilo-ohms @ 20ºC Not fitted
Capacitor 25 microfarads 370/450 VAC 50/60HZ
Fan motor winding resistance 47.2 ohms at 20ºC
Closed –3.5ºC
De-ice thermostat
Open 3ºC +/- 1.5ºC
Not fitted
Closed 7ºC +/- 1.5ºC
Evaporator thermostat Not fitted
Open –3.5ºC evap temp
Compressor winding resistance
Run winding - Red & Blue: 3.33 ohms
Start winding - Red & Black: 6.01 ohms at 20ºC
Preventative Maintenance
It is suggested for peak performance that the water heater be serviced annually.
1. Check for discharge from the T&PR valve. When the elements are operating a small
discharge of water may be evident. Operate the valve-easing lever to ensure the valve
opens and resets properly. Always open and close the valve gently. The T& PR valve
should be replaced at 5 yearly intervals.
2. Check for leaks at all cylinder fittings.
3. Check for signs of excessive corrosion on the water heater jacket.
4. Isolate power to the water heater and check all electrical connections for signs of
overheating due to poor connection.
5. Conduct an
'Electrical insulation test' on the water heater. (Refer to page 30)
6. Check evaporator fins and fan blade for build up of dust or debris.
7. Check for sludge build up and if necessary drain and flush tank.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
4
Operation
Normal Operation
The 550 and 551 series heat pump water heaters utilise either R22 or R409A refrigerant to
transfer heat from the atmosphere to the water stored in the cylinder.
When the compressor thermostat contacts close the compressor and evaporator fan motor
commence operation. The action of the compressor creates a pressure difference that
causes the refrigerant to circulate through the sealed refrigeration system.
The refrigerant enters the evaporator as a liquid, as heat is absorbed from the atmosphere
by the refrigerant it changes state, at low pressure, from a sub cooled liquid to a super
heated vapour or gas (evaporates). The vapour then enters the compressor and obtains
more heat, known as heat of compression, and passes into the spiral condenser (heat
exchanger) as a super heated vapour at high pressure.
The spiral condenser (heat exchanger) is fixed in close contact to the inner wall of a tube
fitted in the centre of the cylinder. As the refrigerant passes through the condenser it gives
off heat to the cylinder surface, which is absorbed by the water. As the refrigerant gives off
heat it cools and changes state back into a liquid (condenses). The refrigerant then enters
the evaporator again and the cycle is repeated.
A metering device, called a TX valve, is positioned between the condenser and evaporator
to control, or meter the flow of refrigerant into the evaporator. The TX valve senses the
temperature of the suction line and automatically meters the flow of refrigerant based on
the detected temperature.
Defrost Operation
At low ambient air temperatures, typically below 10ºC, it is possible for the evaporator to
freeze.
55027500
If an evaporator surface temperature of –3.5ºC is detected a thermostat, called the de-ice
thermostat, activates a bypass solenoid. This solenoid allows a proportion of super heated
vapour from the compressor to bypass the condenser and directly enter the evaporator
assisting the evaporator to defrost. The De-ice thermostat opens at 3 degrees, which
causes the solenoid to close cutting of the supply of super heated vapour to the bypass
pipe, at this point normal heat pump operation is resumed.
55127507
If an evaporator surface temperature of –3.5ºC is detected a thermostat, called the
evaporator thermostat, cuts power to the compressor and evaporator fan and activates the
booster element. The booster element is controlled by a Robertshaw thermostat and will
provide 130L of hot water. During this period the evaporator will naturally defrost. The
evaporator thermostat opens at 7 degrees, cutting power to the booster element and
reactivating the compressor and evaporator fan motor, at this point normal heat pump
operation is resumed.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
5
Refrigeration Terms and their Meaning
Sub Cooled Liquid – A substance below its saturation temperature at a given pressure.
Super Heated Vapour – A substance above its boiling point at a given pressure.
Saturated Vapour – A substance at its boiling point at a given pressure.
Latent Heat – Hidden (invisible) heat removed or added to a substance that results in a
change of state (i.e. liquid to a vapour) without an increase or decrease in temperature.
Heat of Compression – The additional heat added to a substance by the act of
compressing it.
Low Side – Components and pipe work of a refrigeration system operating at low
pressure, generally considered to be the evaporator, suction line and accumulator.
High Side – Components and pipe work of a refrigeration system operating at high
pressure, generally considered to be the condenser, discharge line, liquid receiver/filter
drier and compressor case where a rotary compressor is utilized.
Boil Off – The action of a substance as it absorbs heat and changes state (evaporates)
from a liquid to a vapour (gas).
Give Up Heat – The action of a substance as it releases heat and changes state
(condenses) from a vapour (gas) to a liquid.
Components and their Function
Temperature and Pressure Relief Valve - A valve designed to provide automatic relief by
discharging water in case of excessive temperature, pressure or both.
Never fit a T&PR Valve with a pressure rating greater than that indicated on
the product-rating label.
Pressure Limiting Valve (P.L.V.) - A valve that controls its outlet pressure to a
predetermined limit.
Outlet Delivery Tube (Dip Tube) - A plastic tube installed in the hot water outlet of the
water heater cylinder to conduct water from the highest point to the outlet connection. It
also acts as a fitting liner.
Diffuser - A plastic device installed in the cold water inlet of the water heater cylinder to
assist with stratification. It also acts as a fitting liner.
Fitting Liner - A plastic tube installed in the cold-water inlet of the water heater to provide
protection against corrosion through the life of the water heater.
Anode (Sacrificial) - A metal alloy electrode installed in the water heater cylinder that by
galvanic action protects the cylinder from corrosion.
Thermostat - A device responsive to temperature that controls the supply of electrical
energy to the compressor, which results in the stored water being maintained at the
required temperature.
De-Ice Thermostat - A device responsive to temperature that controls a solenoid to
perform de-icing of the evaporator in cold weather.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
6
Evaporator Thermostat - A device responsive to temperature that controls the active
supply between the compressor circuit and the booster element circuit.
Compressor - An electro-mechanical device that adds heats to the refrigerant by
compressing it, known as “heat of compression” the resulting increase in refrigerant
temperature increases its pressure and causes the refrigerant to circulate through the
system.
Evaporator - A finned copper coil mounted on top of the water heater. The refrigerant
enters as a liquid, as it passes through the coil it absorbs heat from the surrounding
atmosphere and “boils off” (evaporates) to a gas.
Condenser - A copper coil soldered to the cylinder wall. The refrigerant enters as a gas,
as it passes through the coil it transfers (“gives up”) the heat absorbed via the evaporator
to the stored water, during this process the refrigerant cools and changes state
(condenses) back to a liquid.
Receiver Filter Drier - This device, fitted between the condenser and thermal expansion
(TX) valve, receives and stores liquid refrigerant from the condenser for delivery to the
evaporator. The receiver also incorporates a filter and drier to trap impurities and remove
moisture from the sealed refrigeration system
Accumulator - This device, fitted in the suction line prior to the compressor, is designed to
accumulate and prevent liquid refrigerant from entering and damaging the compressor.
Any liquid refrigerant is evaporated or “boiled off” and converted to a vapour by the
accumulator.
Thermal Expansion (TX) Valve - A valve, installed between the condenser and
evaporator, that controls (meters) the amount of refrigerant delivered to the evaporator.
The TX valve has an external temperature sensor fitted to the suction line and increases or
decreases the refrigerant flow to the evaporator depending on the detected suction line
temperature.
Thermal Cut Out (Overload) - A manual reset temperature sensitive device that
automatically cuts off the supply of electrical energy to the compressor or boosted
element.
Heating Unit (Element) - A tubular device containing an electric resistance element that
converts electrical energy to heat. Standard element ratings are 2.4 and 3.6kW.
Common Faults
When a complaint is lodged about the performance of a hot water system there are a
number of causes that should be checked and eliminated. In an attempt to pinpoint the
most likely cause it is important to discuss with the customer their reasons for the
complaint, the duration of the problem, any change in circumstances or usage and recent
weather conditions. This information in conjunction with the following listed common
complaints will assist you in locating the most likely cause. All procedures assume there is
water flowing through the water heater.
Discoloured water - This may be the result of discoloured water entering from the cold
water mains. Check if the cold water is also discoloured.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
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Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
7
Excessive hot water usage - The complaints of insufficient hot water and no hot water
can on many occasions be attributed to hot water usage exceeding the capacity of the
water heater to provide hot water.
When first attending a call of this nature it is essential to establish the probable hot water
usage by querying the usage habits of the household and compare this with the potential
delivery of the model water heater installed. It can then be established if the usage is
within or outside the capacity of the model. The areas to look at for excessive usage are:
1. Automatic washing machines.
2. Showers exceeding 12 litres/minute for mixed water and 5 minutes in duration.
3. Two or more showers operating at the same time.
4. Change of occupancy or number of persons increased.
5. High water pressure area. (Excessive pressure relief valve discharge)
6. Plumbing leaks
7. Crossed connection
Water hammer - A water heater will not cause water hammer, however valves associated
with the water heater may be the source of the problem i.e. cold-water stopcock, nonreturn valve or relief valve.
Most water hammer problems are associated with plumbing, hot and cold or appliances
i.e. solenoid valves, ballcocks, loose pipes, sharp angles in pipe work, faulty or worn valve
parts, loose tap washers or neighbouring equipment.
High water pressure areas will have more complaints of this nature and the use of a
pressure-limiting valve (PLV) to reduce the household cold-water pressure will usually
solve most problems.
Hot water plumbing leaks - If hot water has not been used for a period of time, feeling
the temperature of the hot water line may give an indication of water flow if the pipe is
warm. The method of checking for plumbing leaks is:
1. Turn off the stopcock on the cold water supply to the water heater.
2. Open a hot tap to ensure the flow of water stops. This will confirm the stopcock is
operating correctly.
3. Turn off the hot tap.
4. Turn on the stopcock to make up the water pressure in the cylinder, and then turn the
stopcock off again.
5. Wait approximately 5 minutes then do either of the following:
a. With your ear close to the stopcock turn it on slightly and listen for any water
passing. If there are no leaks, water should not pass.
b. Open a hot tap while listening for any pressure release. If there is a pressure
release there will be no leaks in the plumbing system.
Mixing or crossed connections - If an automatic dishwasher, washing machine, flick
mixer tap, tempering valve or thermostatic mixing valve is installed there is always the
possibility that the cold water could mix with the hot water through a faulty or incorrectly
installed valve. This is referred to as a cross connection. The complaints of insufficient hot
water, water too cold or excessive discharge from the pressure relief valve may be
attributed to a cross connection. The method of checking for a cross connection is:
1. Turn off the stopcock on the cold water supply to the water heater.
2. Open a hot tap. If water flow is persistent and cold a cross connection exists.
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
8
Product Changes
Refrigerant Conversions
Some 550 and 551 Series Heat Pumps have had problems with the condenser bonding
causing excessive head pressure and tripping of the compressor ECO.
This problem may be rectified by replacing the R22 refrigerant with R409A refrigerant. Two
kits are available to carry out the conversion (refer to technical bulletin TB04-014 and
Procedure 20 of this manual).
Prior to replacing the refrigerant it will be necessary to determine the current operating
head pressure of the refrigeration system with R22, if the head pressure exceeds 3400kPa
the system is not suitable for conversion to R409A and the Heat Pump will need to be
replaced.
551 Series
In August 2004 a number of changes were made to the 551 Series Heat Pump. In order to
identify the change an additional service model number label is positioned adjacent to the
Heat Pump rating label. All heaters with a suffix of ‘A’ are affected by the changes detailed
below.
Robertshaw Thermostat: The EWT1L2-522 thermostat (part number 051333) which
controlled the booster element only, is replaced with a Robertshaw EWT1A1-2 thermostat
(part number 051347) which controls both the booster element and compressor operation.
Derwent Thermostat: The Derwent 52°C single pole thermostat (part number 051337)
which controlled the compressor operation is replaced with a Derwent 85°C double pole
thermostat which is now the over temperature cut out for the element
Refrigerant: R409A refrigerant used in place of R22
TX Valve: The TX valve (part number 180003) is replaced by one suitable for use with
R409A (part number 180024)
Wiring Diagrams
55027500
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
9
55127507 (Manufactured before August 2004)
55127507/A (Manufactured after August 2004)
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
10
Refrigeration Sealed System Diagrams
55027500
55127507
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
11
Performance Graph
Rheem Heat Pump
Recovery Rate (L/h) @ 45°C Rise
50
55
60
65
70
75
10 15 20 25 30 35 40
Air Temperature
Litres
Fault Finding Flow Chart Table
Fault Chart Number Page
1 13
1.1 14
1.2 18
1.3 19
1.4 21
7 31
Compressor not
running
8 33
1.5 18
2 22
2.1 14
2.2 21
2.3 24
No Hot Water
Compressor
running
2.4
24
3 25
Insufficient hot water
3.1 26
Leaking water heater 4 27
Noisy water heater 5 28
Blowing fuse/circuit breaker 6 29
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
12
Fault Finding
Fault Diagnosis
No
hot water?
Is
the compressor
running?
YES
2
YES
Model?NO
1
550275
7
551275
Insufficient
hot water?
NO
3
YES
Leaking
water heater?
NO
4
YES
Noisy
water heater?
NO
5
YES
6
Blowing fuse/circuit breaker
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
13
550275 Power Supply Fault Finding - Chart 1
1
Warning: Terminals may be ‘live’.
Personal Protective Equipment
should be worn
Is 240
volts present at
the terminal
block?
Test 1
1.1
YES
Is
the heater
connected to an
off peak
tariff?
NO
Off peak connection is unsuitable for Heat
Pump models. Connect to continuous tariff or
‘off peak 2’ if available
YES
Is
the isolating switch
turned off?
NO
Restore power and advise customerYES
Is the
fuse blown at the
switchboard?
NO
Fault in household electrical wiringNO
Reset circuit breaker
or rewire fuse
YES
Did
the fuse or
circuit breaker blow
again?
6
YES
1. Heat pump connected to mixed circuit,
possible excessive current draw or another
appliance with a fault
2. Faulty circuit breaker or fatigued fuse wire
3. Unit may be short cycling due to faulty
thermostat
NO
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
This document is stored and maintained electronically by
Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
14
Thermostat Circuit Fault Finding - Chart 1.1
1.1
Is the
evaporator fan
running?
Test 3
Is the
resistance of
the fan motor
correct?
NO
YES
Replace thermostat
1.5
Test 2 - 550275 and 551275
Test 2A - 551275/A
NO
Are the
thermostat contacts
closed?
Isolate power
NO
2.1
Replace fan motor and reset
compressor over temperature
cut out
NO
YES
Is the
fan motor
seized?
YES
YES
Fault in electrical wiring
Locate and repair
NO
Is the
resistance of
the compressor
correct?
Test 4
Replace compressorNO
Is there
240 volts to the
compressor?
Test 6
Fault in electrical wiring
Locate and repair
NO
YES
Has
the capacitor
failed?
Test 5
Replace capacitor and reset
overload
YES
Has the
compressor overload
tripped?
Test 3A
NO
YES
1.2
YES
TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
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Service. All printed copies not bearing this statement in RED are deemed “uncontrolled”.
15
Component Tests 1 – 2A
Test 1
Warning – “Live” equipment Personal Protective Equipment should be worn when
conducting this test.
Using a multimeter set on the AC
voltage scale, measure between
active and neutral on the terminal
block.
Normal voltage is 240 volts
Test 2
Ensure power is isolated before conducting this test
550275 & 551275
Disconnect one wire from the
thermostat and using a multimeter
set on the x1 resistance scale,
measure across the thermostat
terminals.
Normal resistance should be less
than 1 ohm
Test 2A
Ensure power is isolated before conducting this test
551275/A
Disconnect the wire from the terminal
3L of the thermostat and using a
multimeter set on the x1 resistance
scale, measure across terminals 3L
and 4L.
Normal resistance should be less
than 1 ohm.
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