Ufh not heating properly - boiler goes on / off every minute

[pototea]

Update - I had a plumber come today who spent around 1.5 hours looking at it. He couldn' figure out what was wrong so he called grundfos. Grundfos said the pump is not right for underfloor heating, it' too powerful which is why the heating keeps switching off as most likely it's over heating.

Does this sound plausible?

I have a single zone / single loop under floor heating setup in my kitchen.

The original pump fitted was a grundfos upm3 auto l pump.

 

[Dan Robinson]

Sounds like twaddle to me. I fitted a UPS2 today and the stupid pictorial instructions had information on how to set it up for UFH systems.

 

[pototea]

Hi there, I had a third plumber come today. He believes the problem lies with the pump sensor (box in photo).

There is no branding on the sensor so he is unable to replace it with another one. He has suggested removing it all together and advised that its am extra precautionary measure and not really necessary with the room thermostat and blending valve.

Before he comes back to remove the sensor, can anyone advise this is correct and removing the sensor will not cause any issue?

 

[Dan Robinson]

That sensor is there to hold the pump off until Hot Water arrives from the boiler.

If the pump is on, then the sensor is working.

 

[pototea]

Thanks.

Is anyone able to identify from the photos what the brand of manifold Is? There are no markings whatsoever on it.

Potentially it may have been bought from Screwfix or Toolstation in January 2016. These companies only sell John Guest manifolds. Can anyone confirm this looks like a John Guest manifold?

 

[Hot&Cold]

this is an ongoing ufh thread. 2017+ I have wet underfloor heating in my kitchen which I had fitted almost two years ago. The first run of tiles get warm, the remainder stay cool.
Read more: https://www.diynot.com/diy/threads/how-do-i-bleed-my-wet-underfloor-heating.493169/#ixzz5IPEs9gBr

do you have a ufh pipe diagram and is the ufh correctly

Maybe its installed or set up incorrectly,better get an expert onsite fix it. Still got the 440cdi

 

[pototea]

Hi, I've already had three "experts" look at it and no root cause identified by any of them yet.

Unfortunately i don't have a system diagram. It's a single room loop and I have two zones - one for radiators and one for the kitchen ufh.

It initially worked for 2 years after first installed. Then when the pump broke down and was replaced last November it's been one problem after another. Mostly caused by the plumber who fitted the pump the wrong way round so it was working overtime and pumping back up to the boiler for 3 months during the cold period we had.

Yes I still have the Worcester 440cdi boiler - my apologies i wrote the wrong model number of the boiler in this thread.

I've now found the manifold model by googling images. It's a Reliable ZL2532. They don't provide spare parts so looks like the whole manifold needs replacing.

 

[Hot&Cold]

Hi, I've already had three "experts" look at it and no root cause identified by any of them yet.

Have they got x ray vision to inspect the ufh circuit and are they experts on wet ufh,so many wannabe heating tech's around now days. mr

 

[Gasguru]

Why do people buy cheap Chinese carp off eBay...then wonder why it doesn't work? The name says it all

 

[Hot&Cold]

未命名 -1 - Reliable Trading
A Rated Underfloor Heating Single Room Control Thermostatic Pump Blender Mixer

by Grundfos/Wilo
Only 7 left in stock (more on the way). Selling well !


Could be wrong thou,happy to listen