THERMAFLOW LTD | THERMAFLOW® ELECTRIC COMBINATION BOILER |
Tel: 0870 850 5207
27
PART 3 - SERVICING
3.1. Fault Finding
MUST BE CARRIED OUT BY A PERSON COMPETENT TO DO SO
Before trying to operate the boiler make sure that:
The heating system pressure is at 150 KPA (1.5 Bar) when the system is
COLD
and 200 KPA (2.0 Bar)
when the system is at
maximum
temperature.
There is a permanent mains power, (24hr supply) to the terminals marked in the control panel on the
boiler in the schematic diagram on
page 9
of this instruction manual.
There is power at the off peak (Interrupted) supply main switch in the control box at the top of the boiler
(Marked No 17 on the boiler schematic diagram on
page 9
of this instruction manual.
WARNING: BEFORE OBTAINING ACCESS TO TERMINALS, ALL SUPPLY CIRCUITS MUST
BE DISCONNECTED.
IMPORTANT:
ON COMPLETION OF THE FAULT FINDING TASK WHICH HAS REQUIRED THE
BREAKING OR REMAKING OF THE ELECTRICAL CONNECTIONS, THE CONTINUITY,
POLARITY, SHORT CIRCUIT AND RESISTANCE TO EARTH CHECKS MUST BE REPEATED
USING A SUITABLE MULTI- METER.
Type of fault
Check
No domestic hot water or central
heating
~230-240V Supply (24HR)
~230-240V Supply (Off Peak)
System water pressure at 150 kpa (1.5 bar)
External Off-Peak control
Low pressure switch
Master high limit manual re-set thermostat 3rd stage
Manual re-set Over Heat Thermostat 2nd stage
Contactor
Heating elements
No central heating but hot water
at taps
~230-240V Supply (24HR)
~230-240V Supply (Off Peak)
External controls
External Off-Peak control
Low pressure switch
Heating elements
Manual re-set Over Heat Thermostats 2nd & 3rd stage
Temperature at bottom of store
must be above
aqua stat setting
of
25ºC
Is central heating pump operating correctly?
Central heating but no hot water
at taps or temperature diminishes
after a short period
Auto air eliminator in closed position?
Pump valves in the open position?
Figure 17, page 9
Domestic hot water pump is not operating?
Secondary expansion vessel pressure (must be 2.0 -3.5bar)
Hot water blending valve?
Blockage in the primary flow pipe into the plate heat
exchanger?
