UFH help/advice please

[CTO]

Evening all,

Hoping one of you learned souls can offer me a bit of advice/steer in the right direction.

My underfloor heating isn’t heating, well, not much at least. I cranked it up over the weekend and not too much has happened at all. Sometimes one zone seems to get warm, and then cools down. The main zone being the kitchen/diner the floor heats up above being “cold”, but doesn’t get warm.

Last year when the UFH was turned up, the floor was noticeably very warm, as one would expect.

The boiler man has been out today and said that everything boiler and rads wise is fine, he also said he thought the UFH was fine, but I’m sure it’s not and I can feel that it’s not…..

The heating UFH system is two years old, and I’m not sure if maybe it needs bleeding, or if the (I think actuators?) are actuating.

If the “actuators” are the white bits that look a bit like radiator caps in the below pics, then they are warm/hot to the touch… but not much else seems to be.. including the pipe work….

I have taken many pics of things that I don’t understand, in the hope that one of you can advise.

So, over to you. Help me from getting cold tootsies in the morning

Pics are here







Cheers all

[Arrivalist]

How long are you leaving it on for and what’s the blended temperature at the manifold?

[CTO]

It’s been on all day so far… figured it might need a bit of time to warm up… it hasn’t been used since last winter.

Re the blended temp at the manifold. No idea and tbh no idea how I could tell?

Cheers

[hidetheelephants]

CTO said:

it hasn t been used since last winter.

Not particularly helpful, but that may be your problem; keeping the heating on reduces the risk of it going on the fritz, just turn the temperature down/shorten the 'on' time.

[caziques]

There should be a flow indicator on the top manifold. I would be unclipping the actuators, they shouldn't be there in any case - and then checking there is flow when the pump is on.

[Familymad]

All your flow indicators are showing running (litres per min) and you have pressure. The valves show red on the top and are calling for heat. It looks like it’s pulling hot water into the circuits. How long can it call the boiler for ? Our UFH (3 circuits) can call 0500-0900 and 1600-2100. It needs all of it to get the room to temp.

[Arrivalist]

CTO said:

It s been on all day so far figured it might need a bit of time to warm up it hasn t been used since last winter.

Re the blended temp at the manifold. No idea and tbh no idea how I could tell?

Cheers

There should be a gauge that shows the temperature and which can be adjusted.

I can’t see that in your pictures. Although UFH runs at a much lower temperature than radiators, it does need to be warm enough, typically 35-45C.

[Jeremy-75qq8]

Let's look at each component.

1. Grundfos.

This is the pump. They are well known for sticking. Some show a red light when stuck. Some don't.

With it off put a cross head screw driver in and push then twist. You must push or it will not engage the impeller. Does it turn freely ?

A second test you can do briefly is with it on when you push on the screw can you immediately hear and feel the mechanism engage.

2. Mixing valve

This is below the pump. + - changes the temp of the water. There are usually thermometers mounted. You don't have that. As above round an about 40 degrees. Pipes should be warm. You don't want it too hot. Use it thermometer to set.

3. The white things. They are electric valve actuators and. Control the flow.

You can remove them and the valve should open ( the pin will be up and can be pressed down with a blunt object. Do the move freely

4. The glass things on top. They should show zero when off and flow when on ( or valve actuators removed as above )


Finally remember if works on thermal mass. It is not a radiator you need to heat the floor. You usually have a profile of say 22 in the day and 18 at night. It is about consistent heat not blast / off

[Patio]

I think your flow temp is set too low

A close up of the 1st pic looks like mixing valve(white knob under pump) is set at about 32 degrees. That's too low

Turn anticlockwise as far as you can and it should go up to 50/60 degrees

Give that a blast for a day and see what happens

[Arrivalist]

Patio said:

I think your flow temp is set too low

A close up of the 1st pic looks like mixing valve(white knob under pump) is set at about 32 degrees. That's too low

Turn anticlockwise as far as you can and it should go up to 50/60 degrees

Give that a blast for a day and see what happens

Ahhh…. I never saw that dial when I glanced the images.

Depending on the OPs floor coverings I’d be wary going up too high. Maybe start at 40 and go from there?

[Nick Forest]

You say the system (and I assume the house?) is two years old so was a new build install.

Did your heating engineer open up the flush valves and check no debris has built up in the intervening years…being a new build there’s a chance some crap entered into the underfloor circuits and it’s now compacting into a single mass…ask me how I know!

[Patio]

Arrivalist said:

Patio said:

I think your flow temp is set too low

A close up of the 1st pic looks like mixing valve(white knob under pump) is set at about 32 degrees. That's too low

Turn anticlockwise as far as you can and it should go up to 50/60 degrees

Give that a blast for a day and see what happens

Ahhh . I never saw that dial when I glanced the images.

Depending on the OPs floor coverings I d be wary going up too high. Maybe start at 40 and go from there?

Sounds like a plan

Though floor coverings could be part of the problem if it's thick rugs everywhere

Only flooring with temp issues really is karndean type stuff, anything else will be fine

We've got thick laminate and carpet with floor temp set at 50/55 and no problems...