Help! Fuse spur switch on central heating timer panel
- Thread starter Stephen c
- Start date
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That's a Honeywell ST699 programmer.
First of all I would try ensuring that the wires are fixed in place tightly and that programmer is fixed to its backplate properly and the securing screws are tight.
If you want to try by-passing the programmer and are capable of doing it safely the wiring of it is as below:
Removing the programmer exposes the terminals. Linking terminal (L) to (3) and (6) will put the heating and hot water 'on' permanently. You could try this and see if it everything runs OK, if it does then the programmer is most likely the culprit. This test should be done with the programmer left off the backplate, so live terminals will be exposed.
Don't do this test unless terminals (L) (5) & (8) are linked as per the diagram (they probably will be). If they aren't don't proceed and post back.
If it runs OK in this condition without failing, it would appear that the programmer is faulty.
First of all I would try ensuring that the wires are fixed in place tightly and that programmer is fixed to its backplate properly and the securing screws are tight.
If you want to try by-passing the programmer and are capable of doing it safely the wiring of it is as below:
Removing the programmer exposes the terminals. Linking terminal (L) to (3) and (6) will put the heating and hot water 'on' permanently. You could try this and see if it everything runs OK, if it does then the programmer is most likely the culprit. This test should be done with the programmer left off the backplate, so live terminals will be exposed.
Don't do this test unless terminals (L) (5) & (8) are linked as per the diagram (they probably will be). If they aren't don't proceed and post back.
If it runs OK in this condition without failing, it would appear that the programmer is faulty.
Last edited:
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That programmer is a notorious model for failing, personally I wont isolate the power when working on a system with one of those, unless the customer signs a disclaimer to say if it doesnt come back on, then not my fault, best to be replaced, very unlikely to be the fused spur but could be a loose wire, my money is on the programmer
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