Motorised Valve Tripping house electrics

[Peter West]

Hi everyone, just to say this is my first post, I'm not a professional but have had a lot of DIY experience over the years and installed a couple of systems in my time in my houses through the years. So I'm well aware when I'm out of my depth!
My problem is that I'm on my third motorised valve (heating side). The senario is, firstly, the house electrics trip, and after isolating the heating side motorised valve (two port), from the heating circuit, the house works fine once again. When I connect it back and switch in the heating, the valve takes a few seconds to open, then when the auxillary circuit switch close in the valve, bang, the electric trip again. So the fault is in the auxillary switch circuit of the motorised valve. All well and good, I buy a new one, fit it, then probably about 9 months later, the same thing happens again. I'm on my third now. Please any ideas!!, once, I can put down to a faulty valve, but three times, no. There is something else going on. Help please. I forgot to mention, I only replaced the motor head

Peter

 

[Chuck]

I'm well aware when I'm out of my depth!

Throwing parts at a problem you don't understand is a good way to waste time and money. It's not appropriate to diagnose this sort of fault over the internet without eyes-on and the right type of test gear. Eyes-on are needed to check that there are no 'stolen neutrals', and other wiring issues and test gear is needed to check for borderline insulation faults, correct earthing, etc. Also, if it's what I think it is, the whole system should be inspected and checked.

Your best bet is to find a local independent heating engineer or an electrician who is confident with central heating wiring (not all are, ask them). It won't be difficult for someone who knows what they are doing to diagnose and fix.

 

[Peter West]

Thanks for the advice. I've already called my favourite electrician and I'll see what he says. A thing to note is that the auxillary switch is not being switched on, I've just checked with a meter. I'm running the central heating with no problems just by bypassing the switch with a direct connection at the junction box. It's a temporary fix to give us heating until the solution is found. I suspect that it may be the valve is not travelling to compete the contact with the switch, which means the mechanics of the valve itself are not running smooth, I'm about to check it out.

 

[Sharp Point]

What’s tripping, mcb or rcd?

 

[Peter West]

An update, there is no restriction of travel in the valve, it is moving fully. The auxillary circuit switch is closed properly. However I noticed that there is 17 ohms of resistance that doesn't seem right in a switch. I just want to point out if I bypass the switch the whole system runs perfectly.

 

[Peter West]

The RCD is tripping

 

[Chuck]

The RCD is tripping

Which is a definite sign that you have an insulation failure somewhere or the wiring has been done incorrectly and is in a potentially dangerous state.

When did you say your electrician was coming?

 

[Peter West]

I'm waiting for him now, I have at least Isolated the area of the problem. That's one thing

 

[Murdoch]

Valves, electricity and water ... Tripping RCD .... Any evidence of leaks?

 

[Sharp Point]

Have you been replacing the complete zone valve head or just the synchron motor?

 

[Peter West]

No signs of leaks anywhere. Everything looks OK with the valve. I've been replacing the whole motorised head, which includes the auxillary power switch. The motor works fine, at the moment I've isolated the switch from the circuitry and manually completed the circuit for the pump and boiler with a wire. The valve is permanently open when the heating is set to "On", so I can do that. With this arrangement everything is working perfectly. This I must stress is a temporary arrangement to keep the family happy!

 

[Last Plumber]

No signs of leaks anywhere. Everything looks OK with the valve. I've been replacing the whole motorised head, which includes the auxillary power switch. The motor works fine, at the moment I've isolated the switch from the circuitry and manually completed the circuit for the pump and boiler with a wire. The valve is permanently open when the heating is set to "On", so I can do that. With this arrangement everything is working perfectly. This I must stress is a temporary arrangement to keep the family happy!

From what you wrote it sounds like you could have a situation where the valve could close and still leave a switched live to the boiler?
If that is correct, there is a risk of damage to the boiler.

You need a Heating Engineer or a Spark with experience of Heating systems.

 

[Peter West]

Electrician came and found a solution. An interesting one. The auxillary circuit switch in the valve head had blackened showing signs of overheating, hence the electrical failure. We discovered that the heating side was running too hot, and although the boiler thermostat was on the lowest setting the water temperature still felt way too high, those valves have a maximum operating temperature, and we felt that it exceeded this, hence damaged to the switch. Remember this was the third valve head to do this. So now it's over to the plumber to sort out the water temperature and get it within safe limits. The hot water side, no problem, the flow temperature felt much lower on the hot water side when it was running. Too few radiators are on in the house to cool it all down, but the boiler stat should still do it's job. Thanks for all your help.

 

[Peter West]

It's OK last plumber, when I manually switch of the heating, I also switch off the supply to the boiler and pump by disconnecting the wire, like the valve head would do if it was working properly. This is only a temporary measure to keep thing going this all is sorted.

 

[Gasmk1]

to be honest i have never heard of that happening are you sure there is no water ingress a slight drip or seep from the valve body

 

[Peter West]

No, it was examined closely, no water, the switch was black on one corner where it had burnt out.

 

[Murdoch]

No, it was examined closely, no water, the switch was black on one corner where it had burnt out.

That blackening was NOT caused by the temperature of the water .........

 

[ShaunCorbs]

nope there rated to around 85 dc which is more than enough for your system

somethings gone wrong with the head and needs changing either head only or whole valve

 

[Peter West]

You are all correct, thanks guys. Fault found a leaking gate valve higher up the pipe and water running down onto valve, only showed up when cold! Fixing as we speak. Thanks for your advice, it's what got me looking

 

[Ric2013]

Glad you sorted it, and thanks for letting us know.