Help Needed: Horstmann H37XL Controller Wiring

[mill9stream]

Sorry if this is a silly question but I'm not an electrician ...

I have a faulty Horstman H37XL controller and, having done some basic research, thought it would be easy enough to replace like for like. Having taken the old controller off the wall, I saw that one of the neutral cables wasn't connected!  To a non-electrician like me, that doesn't seem right. To which terminal should it be connected or is it OK left just as it is?

https://1drv.ms/u/s!ApgSEIQipJnDjsx61HDxO8XgEy4r0w

Thanks for any help.

Pete

 

[Geoff1946]

Well the end hasn't been stripped, so its not fallen out. That suggests it is just a spare.

It isn't possible to see exactly how the circuit is wired without seeing where the two cables go.

If it worked before, and the timer became faulty then just replacing it with an identical new one should be fine.

 

[Sharpend]

Before you go taking it off, have a look to see if this neutral has broken, so you may see two pieces of copper in neutral terminal rather than just the one, I can’t see the picture so can’t say myself. ?? 

@Geoff1946 can you see from pic at all?? 

 

[Geoff1946]

Before you go taking it off, have a look to see if this neutral has broken, so you may see two pieces of copper in neutral terminal rather than just the one, I can’t see the picture so can’t say myself. ?? 

@Geoff1946 can you see from pic at all?? 

Yes. I'll post it below.   (I hope; I don't often post pictures)

 

[Sharpend]

Thanks for pic Geoff

clears my theory! 

 

[Doc Hudson]

Sorry if this is a silly question but I'm not an electrician ...

I have a faulty Horstman H37XL controller and, having done some basic research, thought it would be easy enough to replace like for like. Having taken the old controller off the wall, I saw that one of the neutral cables wasn't connected!  To a non-electrician like me, that doesn't seem right. To which terminal should it be connected or is it OK left just as it is?

https://1drv.ms/u/s!ApgSEIQipJnDjsx61HDxO8XgEy4r0w

Thanks for any help.

Pete

There would appear to be nothing wrong with that wiring in my opinion.  Traditional Y-plan heating circuits need a live-Neutral & Earth supply to the controller. And the controller only needs to give three Live outputs; (Heat On - Water On - Water Off).  These are needed to position the valve correctly to heat up either water or radiators or both. The wiring has quite correctly being done with 1x 3-core cable to the controller and 1x 5-core cable providing an earth and the three live outputs. (the neutral on the 5-core flex is not needed).  So I would swap your controller if you have already bought it, but I would also add faulty symptoms may be related to a sticking valve.

Heating valves have an electrical contact to output a supply to fire the boiler. A trigger signal from your controller should make the valve operate, move into position, then fire the boiler. (You don't want the boiler firing if the valve is closed!) So if the valve sticks or the switch does not work, a perfectly good controller will not be able to operate the boiler.

Doc H.

 

[ProDave]

What makes you think it is the programmer at fault?  It is usually the 3 port motorised valve. There are 2 micro switches inside them that often fail, or they can just jam up mechanically so the little motor does not have enough power to turn them.

Most times you can remove the actuator head from the valve body.  First check that the valve spindle turns freely.  If so check the actuator head moves to the 2 different positions as commanded.

Post the symptoms. Fault finding by random replacement of parts rarely works well.

 

[kerching]

Well my goggling says its a 3 channel prog

2ch

1hw

so why did you swap,it?

what was it/wasn't it doing?