Load Module Dorman Smith 63A Under-Floor Heating Contactor

[Dambo]

Hi guys,

Just after a bit of advice regarding the above if possible - I've recently been round to a customer's apartment as they explained their under-floor heating wasn't coming on anymore and they believed the heating controller, with it being old, was at fault. It did initially appear to be the problem as it was no longer functioning correctly. The under-floor heating is fed through a 63a heating contactor in the consumer unit. Having replaced the heating controller the under-floor heating still isn't coming on. I've checked each of the separate switches for the various under-floor heating in the property and there is no power going to any of them when the heating controller is on. I've checked the contactor in the consumer unit and there's 230v supplying it but nothing coming out of it. Is it a simple case of replacing the heating contactor? I've to be honest and say I don't do a lot of work on under-floor heating and haven't come across such a heating contactor before. Any advice would be greatly appreciated

 

[kme]

Dambo:

A contactor is a contactor. End of. 

It doesn`t really care what the load is - all it wants to do is switch things on and off.

There ought to be six connections.

The feed terminals ( you`ve got 230V on em )

The load terminals ( the underfloor load is connected to this)

The control, coil or firing terminals (usually marked A1 and A2).

Now - the heating controller( possibly via thermostats) will supply the coil with voltage. If the coil has supply, but no output - contactor coil is toast.

If there is no supply to the coil ( one is prob. constant N, the other a switched live) - you can "jump" the coil, to prove the contactor (or just resistance test it).

Unlikely to be a failed 63A contactor in a domestic environment - however the coils CAN give out.

More likely to be a fault in the control circuitry, to be honest.

Need more info / wiring diagram for more.

 

[NozSpark]

Dambo,

Before you go replacing anything else you really need to do some testing otherwise it's going to get un necessarily expensive for someone.

Like KME said the contactor will have 6 terminals.

Firstly check that it's getting a supply, then check that you're getting a voltage to operate it at A1 wrt A2, then you need to check that the contactor is physically operating (you'll hear a clunk) and then check the output side.

 

[Dambo]

Thanks guys. You're right NozSpark, I don't want to start replacing things that might not be damaged. Regarding the clunking noise - When the thermostat is switched on the contactor does make a clunking noise but when i've then checked the output side of the contactor there's nothing coming through.

 

[NozSpark]

So now you now need to treat it just like a double pole switch (which it is, just operated by an input signal). You might find out that one of the contacts has failed - I have had this before on a star/delta contactor

 

[SPECIAL LOCATION]

Hi guys,

Just after a bit of advice regarding the above if possible - I've recently been round to a customer's apartment as they explained their under-floor heating wasn't coming on anymore and they believed the heating controller, with it being old, was at fault. It did initially appear to be the problem as it was no longer functioning correctly. The under-floor heating is fed through a 63a heating contactor in the consumer unit. Having replaced the heating controller the under-floor heating still isn't coming on. I've checked each of the separate switches for the various under-floor heating in the property and there is no power going to any of them when the heating controller is on. I've checked the contactor in the consumer unit and there's 230v supplying it but nothing coming out of it. Is it a simple case of replacing the heating contactor? I've to be honest and say I don't do a lot of work on under-floor heating and haven't come across such a heating contactor before. Any advice would be greatly appreciated

I simply cannot believe you have gone replacing some parts without testing out other parts of the circuit...

As Noz said...

best advice..

Test first..

replace second!!

 

[steptoe]

I simply cannot believe you have gone replacing some parts without testing out other parts of the circuit...

As Noz said...

best advice..

Test first..

replace second!!

if it didnt work properly anyway then it still needed replacing,

ok, so OP has given himself more hassle having to make another visit,

but what harm has been done by replacing a defunct part anyway?

I do agree with the sentiment test first replace when proven faulty though, but sometimes it can be just as easy to simply replace a known non functioning part to start with, then see where the problem lies, its not always possible to test some types of controller without specialised kit.

 

[SPECIAL LOCATION]

     if it didnt work properly anyway then it still needed replacing,

ok, so OP has given himself more hassle having to make another visit,

but what harm has been done by replacing a defunct part anyway?

I do agree with the sentiment test first replace when proven faulty though, but sometimes it can be just as easy to simply replace a known non functioning part to start with, then see where the problem lies, its not always possible to test some types of controller without specialised kit.

But...

its not rocket science to manually operate and test a contactor!!

unless I been on toooooo much... Guinness   Guinness   Guinness   Guinness Guinness  Guinness   

 

[steptoe]

but it is for programmers,

fair enough, you can link them out, still doesnt prove if the programmer is working though.

 

[Dambo]

You are right SPECIAL LOCATION but the programmer was no longer working and needed to be replaced anyway. As I mentioned I haven't come across these contactors before and didn't have the prior knowledge to know how to verify it was still operating correctly or otherwise. I assumed (wrongly as it is ) that the programmer alone was at fault.

 

[M107]

Snubber needed or the new controler will go tits up same as the old one.

 

[kme]

Concur with my friend