gledhill Torrent GreenHeat OV TGH140 Design, Installation & Servicing Instructions page 22

SERVICING AND MAINTENANCE
The Torrent GreenHeat printed circuit control board/display has been designed to be
fully automatic whilst able to provide functional and diagnostic information to the
householder/installer.
The board works in conjunction with a number of sensors (thermistors) located as
shown in the diagram below.
Automatic Control Operation
The hot water temperature is controlled by sensors on the cold mains pipe to the plate
heat exchanger and the domestic hot water outlet from the plate heat exchanger.
The cold mains sensor checks for a drop in temperature every second and if the drop
is more than 2ºC, it switches on the hot water pump to raise the domestic hot water
temperature to 52ºC (± 2°C).
The control of the hot water temperature is carried out by sensor on the domestic
hot water outlet, adjusting the speed of the hot water pump.
The pump is stopped once the cold feed sensor reaches a temperature of above 30°C.
The following checks should be carried out by the installer before calling the manufacturer.
Noise When Hot Water Tap Is Opened/closed
If the plate heat exchanger pump is noisy when the hot water tap is opened, then
check the level of water in the F & E cistern and vent the pump if necessary.
Water hammer - loose pipework and/or tap washers and/or washing machine valves.
Causes of 'Unsatisfactory Hot Water Service'
See table opposite.
Over ow from Feed and Expansion Cistern
Check that the controlled level of water in the cistern is at the correct level. Adjust if
required and check the ballvalve is shutting o the water supply.
FAULT FINDING
Fault Condition Possible Causes
- Thermal store is cold/DHW
pump is permanently stuck
- Temperature sensor or
DHW temperature
printed circuit control
remains cold
board is faulty.
exiting the taps.
- The water level is low in the
F&E Cistern
DHW temperature - DHW pump keeps sticking
uctuates wildly intermittently
when ow is - Hot & cold crossed at
Domestic Hot Water
Store Sensor steady appliance.
- DHW printed circuit control
DHW temperature
board and/or temperature
exceeds and
sensor is/are faulty.
remains well above
- Thermostats set to high see
Hot Water
60°C when the
Sensor pages 23 and 38 for details.
ow rate is low.
- Other heat sources failed
Cold Water
- Incorrect plumbing
Sensor
arrangement
- No power supplies/fuses
Store not heating
are blown.
- Overheat stat has tripped.
- One or both immersion
heaters have failed.
Page 42
SERVICING AND MAINTENANCE
Normal - standby state
Indicate system status
S2
Press S2
Press Press Press
Sensor temperature
S1 S1 S1
reading
Press S2
Press Press Press
Control set-point
S1 S1 S1
reading
Press S2
Press Press Press
Fault code indicator
lock outs S1 S1 S1
Press S2
Press Press Press
Fault code indicator
block outs S1 S1 S1
2 DIGIT ACB BOARD DISPLAY FLOW CHART
Appliance Control Board
The appliance control board (shown above) has a 2 digit display and 2 push buttons
which are used to check the status of the appliance, check and set its identity and
interrogate it for the current faults and the fault history.
The 2 digit display is controlled by 2 buttons S1 and S2. The ow chart of display
modes is shown above. Generally, each press of button S2 cycles the display from top
to bottom and each press of button S1 cycles the display functions from left to right.
The button S2 is also used to reset the appliance i.e. clear the lockout errors and reset
the appliance.
If S1 is ashing on its own, the system is running normal.
If a sensor error is detected one of the following three error codes ash alternately
with the sensor number instead of the temperature
E1 Open circuit
E2 Short circuit
E3 Temperature greater than 99°C
A code of FF indicates the fault location is empty.
S1
S2 S1
Press
S1
Press
S1
Press
S1
Press
S1
APPLIANCE CONTROL BOARD (A.C.B)
Display in Normal (Standby) Mode
In the standard/normal mode the 2 digit display
indicates the status of the appliance inputs
and outputs by switching on the appropriate
segments of the display.
FAULT FINDING
Page 43
2 digit
display
2 push
buttons
Main
processor