Fault Finding - gledhill BoilerMate CP 120 Design, Installation & Servicing Instructions

The BoilerMate CP appliance control panel and printed circuit control board/display
have been designed to be fully automatic whilst able to provide functional and
diagnostic information to the householder/installer.
The panel/board work 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 S3 and S4.
S3 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 S4 adjusting the
speed of the hot water pump.
The pump is stopped once S3 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.
Overfl 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 off the water supply.
Condition
DHW
temperature
remains cold
exiting the
taps.
DHW
temperature
fl uctuates
wildly when
fl ow is steady
DHW
temperature
exceeds and
remains well
above 60°C
when the
fl ow rate is
low.
Store not
heating
Page 23
SERVICING
S6
On/P Heater
Off/P Heater
Sensors
S3 DHW inlet sensor
S4 DHW outlet sensor
S6 Store sensor
Fault
Possible Causes
- Thermal store is cold/DHW
pump is permanently stuck
- Temperature sensor or printed
circuit control board is faulty.
- The water level is low in the F&E
Cistern
- Overheat immersion stat tripped
- Immersion heater has failed
- DHW pump keeps sticking
intermittently
- Hot & cold crossed at appliance.
- DHW printed circuit control
board and/or temperature
sensor is/are faulty.
- Immersion heater thermostat
temperature setting too high
should be 75°C.
- Power supplies/fuses are blown.
- Overheat immersion stat tripped
or failed.
- Control system not working
correctly

FAULT FINDING

S4
S3