Replacing Central Heating - Baffled!

[paullewis20]

My central heating controller (Potterton EP2002) stopped working yesterday so I set out today to replace it. I bought a compatible alternative (XXX) and have wired it according to the diagram i.e. N L 1 2 3 4 - However there are only two other wires in addition to the neutral and live so the 1&2 connectors are empty - I think this is right though looking at the diagrams?

However when I turn the power back on, the display is really really faint (i.e. an't really see it) and the boiler is not firing at all?

Totally baffled and could do with some help - Any ideas!

 

[Softus]

Any ideas!

Please describe the original symptoms, and provide the make & model of the new programmer.

 

[paullewis20]

Hi, Thanks for the reply - the original symptons were that the potterton controller had stopped working altogether - i.e. no display, buttons not working and not firing the boiler. the new controller is a drayton Tempus 7.

Thanks.
Paul

 

[Softus]

Well I can think of a few basic checks.

Check the polarity of your mains power supply. If you don't have a suitable purpose-made tester then use a voltmeter to verify 240V on phase-neutral and phase-earth, and 0v on neutral-earth.

Where is the fuse for the heating system - in a plug or an FCU? Check that the rating of the fuse is 3A. Try the fuse in the plug of a table lamp to make sure it's not damaged.

Is there really power to the programmer? Check with a voltmeter, and connect a test lamp across the N/L terminals.

Your interpretation of the terminal connections is correct, but check that both of the 'system' and 'day mode' jumpers (on the back) are in position.

Disconnect all wires from terminals 1, 2, 3, 4 on the programmer. It should still operate with all outputs removed, so if everything else is correct, and the programmer doesn't work, then I'd say you have a faulty one.