Central Heating Repairs: The Programmer
CHECKING THE PROGRAMMER
It’s not possible to repair a programmer, so if it proves to be faulty it must be replaced. But first, make sure the connections between the programmer and its backing plate are sound.
♦ Turn off the power supply.
♦ Find the smallholding the programmer to its backing plate (it may be hidden on the underside of the casing) and undo it.
♦ Lift off the programmer unit. Check that the wires running into the backing plate are all securely held in their terminals. Then check that the terminals linking the unit and backing plate are clean and making good contact.
♦ Replace the programmer unit, switch on the power and re-test.
Replacing a programmer
If you are sure the programmer is faulty, remove the unit again and take it to a plumber’s merchant to obtain a matching replacement. This will simply slot on to the existing backing plate.
If you can’t obtain an identical model, buy one offering the same functions and replace the backing plate as well. Check first that the terminals on both the existing and the new backing plate are labelled, so you know where the wires go.
To fit, remove the old backing plate from the wall leaving the wires intact, then fix on the new plate and transfer the wires one by one.