Product Changes; Wiring Diagrams - Rheem 55027500 Service Instructions Manual

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
8
Date of Issue: 5/11/05
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