Worcester GREENSTORE Instruction Manual page 41

High Heat transfer fl uid delta T8/T9 (GT8/GT9)
The heat pump gives an alarm when the temperature difference between the
sensors T8 (GT8) and T9 (GT9) is too high.
Possible cause 1: Insuffi cient fl ow over the heat pump.
Action: 1. Check that the heating system pump has not jammed.
2. Check that all the valves are open. The thermostat
valves should be fully open and in underfl oor heating
systems at least half of the coils should be fully open.
3. Increase the speed of the heating system pump.
If the actions above do not work please refer to page 13 reference fi tting
bypass and an external main pump G1(P1).
Possible cause 2: The fi lter on the primar y circuit is blocked.
Action: 1. Clean the fi lter.
High return to the heat pump T9 (GT9)
Sensor T9 (GT9) in the heat pump stops the compressor if the temperature
of the return water from the radiators becomes too high. The limit is at
approximately 57ºC.
Possible cause 1: The temperature setting is too high.
Action: 1. Lower the temperature setting (Temp. incr. /
decr.).
Possible cause 2: The hot water temperature is set too high.
Action: 1. An alarm is given in hot water mode. Contact the
Technical Support Department to adjust the hot
water temperature.
Possible cause 3: The valves on the radiators or underfl oor
heating system are closed.
(Only applies if a bypass is fi tted)
Action: 1. Open all valves.
2. Press the Ackn. button.
Possible cause 4: The fl ow across the heat pump is greater than
the fl ow in the heating system.
(Only applies if a bypass is fi tted.)
Action: 1. Reduce the speed of the heating system pump or
increase the speed of the main pump in the heating
system.
Increase the speed of the heating
system pump:
Use a screwdriver or a coin to increase
the speed of the heating system pump.
Turn one step anti-clockwise.
The heat pump starts automatically when
the temperature drops.
Lower the speed of the heating sys-
tem pump:
Use a screwdriver or a coin to lower the
speed of the heating system pump. Turn
one step clockwise. The lowest speed
should be avoided.
41
What to do if a fault occurs
ALARM GT8/GT9
High HTF delta
060822 16:08:15
Info Ackn.
Note
ALARM (GT9)
High return HP
060822 16:08:15
Info Ackn.
Note