TEMPERATURE DIFFERENTIAL PRIMARY HEAT EXCHANGER (FAULT CODE)

Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4

CH Demand

Attach temperature probes to flow & return pipes at the bottom left of the combustion chamber

WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure

Mains Power On

Measurement:

Cancel purge cycle & if required, reset boiler.
Allow burner to ignite and CH to operate and reach a reasonable
operating temperature, approximately 55°C.
Measure the temperature differential across the primary heat exchanger.
Expect a differential of approximately 22°C or less.

Note:
1. Initial temperature differential may be greater than 20°C when system is heated from cold, but should start to reduce as the return temperature rises.
2. To reduce the time for the test the heating load can be
reduced by turning off some radiators.