Benchmark SysteMate 125 97-317-26, Design, Installation And Servicing Instructions, Page: 32 / 44

Page 32
3. Causes of ‘Unsatisfactory Space Heating’
Check the boiler thermostat - this should be
set at maximum.
Check that the boiler fl ow temperature before
it is switched off is adequate - it should not
be less than 80°C.
Check the operation and the settings of
the heating programmer and the room
thermostat.
Check that the heating system pump is
circulating the water to the radiator circuit.
If some rooms are not being heated properly,
then balance the system, adjust the pump
speed and check the operation of the
thermostatic radiator valves (if fi tted).
Overfl ow from Feed and Expansion Cistern
Check that the controlled level of water in the
cistern is no higher than necessary. Adjust
if required.
3.4 FAULT FINDING
Despite everyone’s best efforts some problems could occur and lead to complaints
from the householder.
Complaints can be grouped into the following three main categories:-
1. The system is noisy
2. Hot water service is unsatisfactory
3. Space heating is unsatisfactory
The following checks should be carried out by the installer before calling the
manufacturer.
1. Causes of a ‘Noisy’ System
Noisy pump operation
Check the level of water in the Appliance F & E cistern - adjust and vent the plate
heat exchanger pump and system if necessary.
Check and if necessary adjust the pressure in the heating/primary system and
vent the system.
Check the pump speed setting of the boiler pump - reduce if necessary but ensure
that the temperature rise across the boiler does not exceed 11°C.
Check the pump speed setting of the heating pump - reduce if necessary but ensure
a temperature difference across the fl ow and return does not exceed 11°C.
Check and adjust if necessary the heating system bypass valve.
Check that the radiators are correctly balanced.
Noisy boiler operation
Check the fl ow rate through the boiler at full gas rate by measuring the temperature
rise across the boiler. If the temperature rise is greater than 11°C, then increase
the pump speed.
Check
and adjust if necessary the pressure in the heating/primary system.
Check and vent the system if necessary.
Noise when hot water tap is opened
If the plate heat exchanger pump is noisy when the hot water tap is opened,
then check the level of water in the appliance F & E cistern and vent the pump
if necessary.
Water hammer - loose pipework and/or tap washers.
2. Causes of ‘Unsatisfactory Hot Water Service’
Check that the SysteMate is full of water i.e. level of water in the appliance F & E
cistern is correct when system is cold.
Check boiler thermostat - this should be set at maximum.
Check that the boiler fl ow temperature is adequate when it stops fi ring. Boilers
should provide a fl ow temperature of 82 ± 3°C but temperatures as low as 76°C will
allow the SysteMate 2000 to provide a satisfactory performance.
Check that the store is charging to at least 73°C.
Check that the hot water plate heat exchanger pump starts when the hot water tap
is opened and stops shortly after it is closed.
Check that the plate heat exchanger pump is set at maximum speed.
Check that the space heating and hot water load is not greater than the boiler output
and that the SysteMate 2000 model is suitable for the type of dwelling.
If all the above checks are satisfactory then it is possible that the performance of
the heat exchanger is impaired by scale. In this case the hot water fl ow rate will be
noticeably less than the cold water fl ow rate. Replace with a factory exchange unit
and re-check hot water performance.
3.0 SERVICING
The ACB can be used to establish/check
the operating and set temperatures of the
appliance as well as identify faults on any
of the 3 sensors. This is done by operating
switches SW1 and SW2 as shown opposite and
reading the LED display. (See page 27)
Store T1, PHE T2, and DHW T3 indicate the
current value being read by the store, PHE
and DHW sensors respectively. The location
of the sensors is shown in the diagram shown
opposite/below.
T1 ON and T1 OFF show the store temperature
set points which are automatically reset on
each boiler cycle to match the temperature
produced by the boiler.
T1 ON shows the temperature at which the
store will call for heat, i.e signal the boiler to fi re.
T1 OFF shows the temperature at which the
store will be satisfi ed, i.e signal the boiler to
switch off.
POWERFLUSHING/CLEANING OF THE
HEATING SYSTEM
If it is proposed to ‘powerfl ush’ the heating
system we would recommend that the
SysteMate appliance is isolated from the
heating system being cleaned. Failure to do
this could seriously damage the appliance.
When carrying out the work always comply
fully with the manufacturers instructions for
the powerfl ushing equipment being used.
If in any doubt please consult our Technical
Helpline.