Rheem 325 II Series Service Instructions Manual page 73

5. Using an accurate thermometer, measure the
temperature of the suction line adjacent to the point
where the TX valve bulb is attached (suction line
temperature).
6. Note the saturated suction temperature indicated by
the gauge. The current superheat setting is the
suction line temperature minus the saturated suction
temperature.
7. Remove the TX valve cap (see diagram opposite)
and use an allen key to adjust the superheat.
Nominal superheat setting is 6K at 10ºC saturated
suction temperature.
To adjust the superheat, turn the adjusting
spindle as follows:
Clockwise =
Anticlockwise =
8. Refit and tighten the TX valve cap to a torque of 10Nm, and apply a „leak-lock‟ sealant
to the cap thread.
9. Refit/re-install the heat pump module, restore power and allow the heat pump to run for
at least 10 minutes – confirm operating pressures are acceptable (refer to page 54).
10. Isolate power and remove gauges.
11. Check the flexible hose connections for water leaks.
12. Refit the heat pump module access cover and restore power supply to the water
heater.
TX Valve Replacement
WARNING: Heat must NOT be applied to plastic components. When brazing
pipework as indicated in this procedure, a heat shield must be used to
prevent the possibility of damage.
1. Remove the heat pump module. Refer to the „Heat Pump Module Removal‟ procedure
on page 62.
2. Remove the heat pump module outer jacket. Follow steps 6 – 14 of the „Outer Jacket‟
procedure on page 62.
3. Remove the insulation to expose the TX valve bulb and remove the bulb from the
suction line.
4. Recover the refrigerant from the sealed refrigeration system.
5. Disconnect the pipework from the TX valve.
6. Braze the replacement TX valve into place, being sure to nitrogen purge. NOTE: The
TX valve must be cooled whilst brazing pipework, to prevent internal damage.
7. Attach the TX valve bulb firmly to the suction line at the 1 o‟clock position and refit the
insulation.
8. Replace the filter drier. Follow steps 4 and 5 of the „Filter Drier‟ procedure on page 67.
TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
This document is stored and maintained electronically by
Reduced refrigerant flow,
increased superheat.
Increased refrigerant flow,
decreased superheat.
(1.25 hours*)
Saturated Suction
Temperature
0ºC
10ºC
15ºC
20ºC
Service. All printed copies are deemed uncontrolled.
Superheat
3K
6K
7K
9K
73