Honeywell programmer

[someonelse]

I have a Honeywell ST6400C programmer for heating & hot water.

Most of the time, hot water is set to 'off', and when I need hot water I press the 'extra hour' button for a full cylinder of hot water.

However, someties when I hit the button, the entire programmer goes off - all lights out, display goes blank. After mayber 2, 3 seconds there's a click & it restarts (back at previous setting).

This does not always happen, and I can see no pattern as to when it will work, or cut out.

Usually pressing 'extra hour' again works, though occassionally it will cut out a 2nd time.

My questions are:

1) what might be the cause & is it an easy fix?

2) if it needs replacing, I'm sure it is an obsolete model, but if there's a comparable replacement model, does it need a sparkie/heating engineer to change (lotsof wiring inside?) or do they unscrew, pull off, push on repacement and screw up?

Cheers.

 

[Breesey]

Have you checked that the front panel is firmly pushed and secured into the back plate, or for a loose live wire?

There are several models that will fit straight onto the existing back plate, including Honeywell's current version of that programmer (ST9400c I think) should you decide to replace.

 

[Breesey]

or do they unscrew, pull off, push on repacement and screw up?

Yes they do