Wiring question on s plan system

[klippy]

Hi there, thanks for taking the time on reading this.

A friend heating engineer of mine has recently updated my y plan central heating system, to a fully pumped s plan system, unfortunately the electrician he uses has let him dow a few times, so feeling fairly confident at electrics, have attempted it myself.

I am using a drayton wiring centre, which makes it pretty straightforward (I thought), I have everything working, valves open when there is a demand, and 240vac sent the boiler which all works fine, and turn off when demand finishes.

My question is, that I have a permanant 86vac on my switch live to the boiler, now this isnt enough to bring the boiler on, but doesnt seem correct, surley it should be 240v or nothing? I have attempted to trace it back, and have also noticed that I have 43vac coming from hw on from the programmer, when the hw button is not turned on, I have changed the drayton programmer, but still have the same voltage.

Before I get a professional in, just looking to check if this is ok, or anyone else experienced this problem, or any tips!

Boiler is a worcester 18ri (pump is wired directly to this, my friend who fitted the boiler wired the perm live, switch live, and pump live, and assures me is correct!)
drayton programmer
honeywell spring return valves
drayton room stat

Again many thanks for any replies.

Bob

 

[SimonJohns]

Sounds like a feed back volatge off your 2port valve

Can you draw a quick diagram of what you have done. And we should be able to find any fault in what you have done

 

[diamondgas]

Hi kippy and welcome to the forum

In my experience low voltage readings are quite common! They use to bring the neon's on on some of the older programmers but that's about all! As long as all is well I wouldn't be to concerned IMHO

 

[klippy]

Thanks simon johns and diamondgas for the quick replies, will attempt a diagram in the morning, just hoping that a perm 84vac on switch live will not damage the boiler in anyway.

Bob

 

[diamondgas]

The feed is most likely coming back from the boiler bob ... saying that it happened a lot on y plans and minimiser programmers in the old days. something to do with a "back feed loop throught the neutrals"....... don't quote me on that coz it was one of those BS terms that bamboozle the none intelectual and send grey matter into overload with the scientists!! LOL