3 Port Valve not functioning as expected..

Hi,

I have a problem that I am hoping someone can shed some light on as I have tried various solutions but always end up back in the same situation..

I have a fully pumped system with a 3port valve.

The problem I have is that the valve stays fully open all the time so if I just want my hot water running then my radiators are also getting hot..

Let me fill you in on some of the details.

I have replaced the motorised valve and also the main programmer but I still have the same problem. If I turn that mains electricity off the valve returns back to the closed position so that I can get hot water without my radiators heating up but as soon as I decide I need heating then the valve opens and stays open and it will only close if the mains are turned off again..

Now the most annoying part is that it does work as expected from time to time but it is very infrequent and most of the time it does not work.

So I am hoping there is someone who can at least give me an explanation as to the cause of my problem just to put my mind at ease.

If you need any more info then please ask.

Thanks in advance

Mark.

How do you know the room stat is working properly?

I didnt think that would make any difference (correct me if I am wrong) because the valve stays open even if I turn the heating off on the programmer..

*sorry I missed that info off my original message*

Check the voltage to the white, orange and grey wires from the 3PV under the various permutations of HW on/off CH on/off etc, then let us know what they are.

EliteHeat said:

Check the voltage to the white, orange and grey wires from the 3PV under the various permutations of HW on/off CH on/off etc, then let us know what they are.

Click to expand...

Sounds like you are having the same thoughts as me, and it is not switching off the power to the 3PV when heating is turned off.

I am not actually an engineer so I am not sure I am brave enough to take reads besides that I am not even sure where my multimeter is at the moment.

If you can give me some general directions on taking the reads then I will give it a go (ie where should I put the multimeters connectors) my multimeter has various settings which I am also not sure which would be the right one?

My main thing at the moment would be to know if this would be something I can get an electrician in to look at or is this going to be a job for a heating engineer?

Only a few electricians are very competent with wiring and fault finding on heating circuits.

A good heating engineer should have no problem but again many cannot do anything when faced with an electrical fault.

It really needs someone with a knowledge of electronics.

Tony

It's simple enough. Take the top of the wiring centre off - assuming that you have a proper one. All voltages are mains AC, so keep one probe on neutral and measure the voltage from the others as requested. What you should end up with is something like this:-

----CH------ -----HW------ ------------- volts --------------
CH STAT HW STAT ORANGE GREY WHITE

ON HIGH OFF NA
ON LOW OFF NA
ON HIGH ON HIGH
ON HIGH ON LOW
OFF HIGH ON HIGH

etc etc

It should be obvious soon enough where the problem is.

EDIT: spaces are nulls and got truncated - oops

This particular fault is quite common. A new valve did exactly this for me. Fault is with one of the microswitches. They're pretty hard to change though, so it means a new valve head.

I would suspect that if you have put a new motorised valve on and the wiring you did is correct that the fault lies else where ?

As mentioned above you need to start testing really with a multimeter to diagnose a heating fault with any accuracy