NO I AM NOT AN UNDERFLOOR HEATING EXPERT!

[Harvest Fields]

Is not a bad price if you need to use a flir camera. Does this model do the job if so that's not bad, I guess quite a good investment

Never used one mate

 

[GH77]

Like Harvest said around £200 on Amazon ... I wouldn't be without mine now, i've now had 3 commercial UFH jobs sorting out systems that others have "commissioned " had one where there was a 240v actuator on a 24v system, the commissioning certificate had a flow Rate written on it! .... i'd like to know where they got that reading from ... i use mine to show the customer when I'm commissioning, they like seeing the loops heating up in the floor

 

[Dilalio]

It's not heating season, so the only demand on the primaries at this time of year, in your average household (correct me if this is not the case and the users are foreign) should be for hot water and reverse circulation would occur if the cylinder is not the last T on the boiler return, thus allowing hot primary return from the cylinder to find its way into the heating circuits.

 

[Harvest Fields]

It's not heating season, so the only demand on the primaries at this time of year, in your average household (correct me if this is not the case and the users are foreign) should be for hot water and reverse circulation would occur if the cylinder is not the last T on the boiler return, thus allowing hot primary return from the cylinder to find its way into the heating circuits.

All of the returns now have non returns on them.

 

[Dilalio]

All of the returns now have non returns on them.

Ok. Then it has to be a wiring issue and primary HW flow is getting to heating circuits via a mzv that is open when it shouldn't be... have you checked for this? Can you confirm that the problem occurs when there is a demand for HW only?

 

[Harvest Fields]

I do like your thinking. But It does not happen when the hot water is on. Only when the UFH is switched on?

 

[Dilalio]

I do like your thinking. But It does not happen when the hot water is on. Only when the UFH is switched on?

Ok. Now getting more of the story which is probably in the previous posts but that's easy to miss until one joins the party
If this only happens on demand for UFH then what is the mzv for the rad curcuit doing at that call? Does it open up? Check wiring to it from stat(s) is there a backfeed that is energising it?
Maybe it's faulty and staying open. I'd isolate it electrically from the circuit and then fault find on it if the problem goes away during isolation.

 

[Harvest Fields]

Ok. Now getting more of the story which is probably in the previous posts but that's easy to miss until one joins the party
If this only happens on demand for UFH then what is the mzv for the rad curcuit doing at that call? Does it open up? Check wiring to it from stat(s) is there a backfeed that is energising it?
Maybe it's faulty and staying open. I'd isolate it electrically from the circuit and then fault find on it if the problem goes away during isolation.

The heating circuit MZV is brand new. I fitted a new one from the suppliers incase the old one was temperamental and no power to the valve when UFH is on at all not even the 50/75volts you sometimes get when they are back feeding.

 

[GH77]

Thermal image it

 

[Harvest Fields]

Thermal image it

Think I will

 

[Dilalio]

I recently had to use TI to locate my son's corn snake which had escaped in the car on the way back from the reptile shop he works at

 

[Dilalio]

Funnily enough, I had to use it in reverse as the the snake is cold-blooded

 

[Harvest Fields]

So, not had chance to buy a TI as yet as so busy. But popped back to this job yesterday. To take a more in depth look. So I have some pictures and I known it is a mess but just after a bit of advice as UFH is NOT MY THING. If you think it is better for me to pass onto an UFH Engineer I will do so. Quick update all rads eventually come on with the UFH 2 port open. But not when the hot water 2 port is open.

 

[Harvest Fields]

Surprised no one has commented. Still pulling my blooming hair out.

 

[ShaunCorbs]

They haven't used an old feed from a rad to heat the underfloor/ supply the manifold have they?

 

[Harvest Fields]

But that wouldnt explain why it has only just starting to do it. The owners is adamant that they used the UFH more then the heating and it defo didn't do it before?

 

[ShaunCorbs]

Heating two port been replaced?

 

[Harvest Fields]

Heating two port been replaced?

Yes mate.

 

[ShaunCorbs]

so the heating doesnt come on with the hot water at all?

 

[Harvest Fields]

No mate the hot water 2 port is perm open as is a thermal store. Rad cold when water only is on

 

[ShaunCorbs]

No mate the hot water 2 port is perm open as is a thermal store. Rad cold when water only is on

why a thermal store?

 

[Harvest Fields]

No idea but presumed it was as the hot water two port was perm open with no timer.

 

[Harvest Fields]

To be honest I thought it was a normal unvented but when I said to a work mate the 2 port was open all the time when there was 240v present he was the one that said thermal store so I went with it.

 

[ShaunCorbs]

No idea but presumed it was as the hot water two port was perm open with no timer.

was it going to the coil?

 

[Harvest Fields]

Yes

was it going to the coil?

Yes mate

 

[ShaunCorbs]

Yes

Yes mate

not a thermal store then

thermal stores have domestic hot going through the coil (opposite to a normal cylinder)

 

[Harvest Fields]

not a thermal store then

thermal stores have domestic hot going through the coil (opposite to a normal cylinder)

That's what I thought but my G3 knowledge is tiny

 

[ShaunCorbs]

That's what I thought but my G3 knowledge is tiny

TBH I would get the underfloor up and running and get it into fault state and see if the other side of the valve is hot if it is close the valve and do the rads cool etc

 

[Harvest Fields]

I have tried that also mate and turned off the temp valve to min on the UFH valve and they still get hot. I have noticed that the pump for the UFH is on the flow though if that makes a difference?