# Anyone here have a clue about underfloor heating?



## swee'pea99 (12 Dec 2022)

Because I don't. And it's freezing .

Bit of background: I burst a pipe earlier this year, fixed it, drained and refilled the whole CH system a couple of times. Refilled/bled all the radiators. All kushti. Completely forgot about the underfloor heating in the kitchen, which we've never touched since it was installed 10+ years ago, and now the kitchen's like a morgue.

I presume I have to 'bleed the radiator' or something, but I'm looking at controls that are completely foreign to me, so I was hoping there might be someone hereabouts who might be able to tell me what to twiddle and that.

What looks to me like the main flight deck looks like this:






...the full monte looking like this:






Is it perhaps as simple as using that Big Red Tap to let water into the system, as I had to do on the main system? If so, how do I know when's 'enough'? Or what? Like I say, I really haven't a clue, so any hints and tips would be much appreciated.


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## si_c (12 Dec 2022)

Looks like there are two radiator bleed-type ports on the right hand side of each loop (I'm assuming the top is the cold and bottom the hot side).

I'd turn the heating on (including the underfloor) and try bleeding the system as a starter.


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## swee'pea99 (12 Dec 2022)

si_c said:


> Looks like there are two radiator bleed-type ports on the right hand side of each loop (I'm assuming the top is the cold and bottom the hot side).
> 
> I'd turn the heating on (including the underfloor) and try bleeding the system as a starter.



Thanks a lot! That makes sense. When you say ports, are these the fellers you're talking about?






So it would be a matter of turning those taps (like using a radiator key) to let water into the system, topping up using the main inlet valve thingy?

Assuming yes (and if not, please say!), any thoughts on which to do first? 

Thanks again.


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## bikingdad90 (12 Dec 2022)

https://www.continal.co.uk/videos/how-to-bleed-your-continal-ufh-system


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## CXRAndy (12 Dec 2022)

It's 3 port flow and return, with only two ports used. The pump attached pumps water around the two circuits. You could switch off the two valves near the pump side. Attached a hose to the other end that are currently capped off. Pump water in and let it flow out of the other valve until no bubbles are seen. I would feed it from hot side, being on the lower side. 

Close off the fill valves and reopen the flow return valves.

Then just ensure the pump works when powered up. Put a screwdriver to your ear and press it on the pump - you will hear it spinning 

Btw underfloor heating is awesome. Had on our last house throughout. Our farmhouse renovation will have it too when we've finished


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## newts (12 Dec 2022)

CXRAndy said:


> It's 3 port flow and return, with only two ports used. The pump attached pumps water around the two circuits. You could switch off the two valves near the pump side. Attached a hose to the other end that are currently capped off. Pump water in and let it flow out of the other valve until no bubbles are seen. I would feed it from hot side, being on the lower side.
> 
> Close off the fill valves and reopen the flow return valves.
> 
> ...


The valve above the pump in the op's picture is a thermostatic blending/mixing valve, not a divertor (mixes flow from boiler & return pipe). Underfloor heating circuits run on a much lower temp than normal radiator circuits.


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## Lookrider (12 Dec 2022)

Theres likely a bleed on the pump as well 
May look like a chrome disc 20mm in diameter with a slot through 
If so just loosen slightly with a flat head driver until water trickles out


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## swee'pea99 (13 Dec 2022)

Thanks all.

Ok, following the vid, I've 'bled' ...but the gauges all remain resolutely on zero, which I can't help feeling can't be right...






Also, I notice that the main CH pressure gauge hasn't changed...which gives me pause, because whenever I bleed radiators I have to let more mains water into the system to get the pressure back up.

Oh, and I can't feel the pump working. It's hot - uncomfortably hot, in truth - but I can't feel any internal vibrations or anything else to suggest that there's pumping going on.

One other thing - there's nothing in the vid about re-sealing the valve-thingies when you're done - these things:






Are they like regular radiator bleed valves - ie, loosen to bleed, then retighten when done?

Any thoughts much appreciated.


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## bikingdad90 (13 Dec 2022)

Have you checked the valves are not stuck? Sometimes when you isolate the plastic spins but the valve doesn’t close/open


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## swee'pea99 (13 Dec 2022)

bikingdad90 said:


> Have you checked the valves are not stuck? Sometimes when you isolate the plastic spins but the valve doesn’t close/open



The 'zone valve' things, as in the pic above your post, seem to me to be working fine - all turning very smoothly and feeling 'right'. Indeed, everything I've twiddled so far at least feels like it's working as it should.


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## figbat (13 Dec 2022)

If the pump is getting very hot but not making any noise, maybe it's seized.


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## swee'pea99 (13 Dec 2022)

figbat said:


> If the pump is getting very hot but not making any noise, maybe it's seized.



Tempting wee screw right in the middle there...






d'you think if I took the cover off I might learn something useful...?


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## Tenkaykev (13 Dec 2022)

swee'pea99 said:


> Oh, and I can't feel the pump working. It's hot - uncomfortably hot, in truth - but I can't feel any internal vibrations or anything else to suggest that there's pumping going on.


Pumps do run very hot as there’s no external cooling fan. The windings are usually rated at 140 C . If you put a large screwdrivers with the blade on the chrome button at the back of the pump body and your ear on the other end you should hear a faint whirring sound as mentioned by others. You could try giving the pump body a few gentle wacks.


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## Tenkaykev (13 Dec 2022)

swee'pea99 said:


> Tempting wee screw right in the middle there...
> 
> the switch is the speed controller
> 
> d'you think if I took the cover off I might learn something useful...?



Use your nose, the smell of burnt insulation is unmistakable.


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## swee'pea99 (13 Dec 2022)

Ok, thanks for staying with me .

No smell of burning. That's good, right? 

But the floor remains cold. 

And the lady of the house remains unhappy. 

Ok, so my setup doesn't look quite like the one in the video, but similar enough that on the top (blue) pipes, I've taken off the caps and loosened the central stem 'till the threads show'. The bottom (red) pipe, I can't get at anything obvious to turn - the gauges being in the way.






I can't help feeling it must be something to do with a lack of pressure in the system, dating back to when I drained everything down. 

I know the right hand one is redundant - it's not connected to anything down below - but looking at the gauges 






...that has to mean litres per minute, I'm guessing. So the fact that both LH & centre gauge are on plumb zero makes me 

Oh, and...


Tenkaykev said:


> Pumps do run very hot as there’s no external cooling fan. The windings are usually rated at 140 C . If you put a large screwdrivers with the blade on the chrome button at the back of the pump body and your ear on the other end you should hear a faint whirring sound as mentioned by others. You could try giving the pump body a few gentle wacks.



I can't actually get to the back of the pump - it's fixed to the wall at the back of a cupboard - but if I put the blade of a large screwdriver to it, and the other end to my ear, I can hear/feel a distinct hum that to me feels like it could easily be a pump pumping. (I have a fish tank, so I is an expert.)

Bottom line, I don't know, maybe it is the pump. If anything is responsible for the L/min flow rate, I guess it's the pump. I don't know.

Anyway, any thoughts, I'm all ears  - and thanks again.


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## swee'pea99 (13 Dec 2022)

Tenkaykev said:


> Pumps do run very hot as there’s no external cooling fan. The windings are usually rated at 140 C . If you put a large screwdrivers with the blade on the chrome button at the back of the pump body and your ear on the other end you should hear a faint whirring sound as mentioned by others. You could try giving the pump body a few gentle wacks.



Yes you could.
And I did.
And...







Mark another one up for the CC crew!

Thanks everyone. Saved me probably £150 to have someone else come round and 'it it wiv a nammer.

The thing I'm not clear about at this point is what state to leave these






in. Usually when I've finished bleeding a radiator, I screw the screw home. But on these, I've found that if I screw the middle one right down, the gauge immediately below - ie, the flow rate - instantly goes from 4ish to zero. 

So, do I screw down one/either? Leave one/either open? 

Any help, as ever, much appreciated.


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## Tenkaykev (13 Dec 2022)

swee'pea99 said:


> Yes you could.
> And I did.
> And...
> 
> ...



If it was me, I'd put everything back exactly as it was pre problem. If It was all tickety boo before the problem then it might well have been a sticky pump. 
Perhaps switch the pump to its highest speed for a few hours to give it a bit of a blast.


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## swee'pea99 (13 Dec 2022)

Tenkaykev said:


> If it was me, I'd put everything back exactly as it was pre problem. If It was all tickety boo before the problem then it might well have been a sticky pump.
> Perhaps switch the pump to its highest speed for a few hours to give it a bit of a blast.



Thanks. I don't actually know how everything was before I started messing about with it, but I've left both valves a bit open for now and fingers crossed for the morning, which is when I should know whether it has actually come back from the grave...

Wish me luck...


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## CXRAndy (14 Dec 2022)

I would suggest you reduce the flow rates down to around 2-3 litre/min. The water then has a bit longer in the circuit to release it's heat energy.


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## Tenkaykev (14 Dec 2022)

swee'pea99 said:


> Thanks. I don't actually know how everything was before I started messing about with it, but I've left both valves a bit open for now and fingers crossed for the morning, which is when I should know whether it has actually come back from the grave...
> 
> Wish me luck...



Always take photos ( pre mobile phone cameras I would make copious notes and drawings)


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## CXRAndy (14 Dec 2022)

swee'pea99 said:


> Yes you could.
> And I did.
> And...
> 
> ...



Just realised what you are doing there. There should be no need to remove the flow indicator, you rotate the bottom section of the valve body( actually yours have a box key top in clear) and you should see the flow rate adjust. Be *Gentle* with the adjustment


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## swee'pea99 (14 Dec 2022)

CXRAndy said:


> I would suggest you reduce the flow rates down to around 2-3 litre/min. The water then has a bit longer in the circuit to release it's heat energy.


Interesting....


Tenkaykev said:


> Always take photos ( pre mobile phone cameras I would make copious notes and drawings)


Oh, I do. It's just that in this case it's a screw that looks pretty much the same whether it's three or four turns up or down.


CXRAndy said:


> Just realised what you are doing there. There should be no need to remove the flow indicator, you rotate the bottom section of the valve body( actually yours have a box key top in clear) and you should see the flow rate adjust. Be *Gentle* with the adjustment


That's very interesting. Are you saying that these things - 





adjust the flow rate, and that by turning the wee perspex 'nuts' on the tops I can adjust the rate down to 2-3 litres/min?

Thanks.


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## CXRAndy (14 Dec 2022)

swee'pea99 said:


> Interesting....
> 
> Oh, I do. It's just that in this case it's a screw that looks pretty much the same whether it's three or four turns up or down.
> 
> ...



Yes, all the manifolds Ive ever had, I adjusted the flow to balance them with either turning the bottom of the indicator or top.

If there is a brand on the manifold-Google installation and setup guidance


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## swee'pea99 (14 Dec 2022)

CXRAndy said:


> Yes, all the manifolds Ive ever had, I adjusted the flow to balance them with either turning the bottom of the indicator or top.
> 
> If there is a brand on the manifold-Google installation and setup guidance



Thanks, I'll have a go. I did look for a brand, but can't see anything helpful.


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## swee'pea99 (15 Dec 2022)

First off, thanks everyone - we're back in business! Warm kitchen, happy missus, hooray for the CC posse!

I've tried running the pump at a higher setting for a few minutes (it seems to have just two: what I thought was high position - three - turns out to be off) and everything seems to be tickety boo. The flow rates are now set at a steady four, and that seems to be working fine. So, thanks again - really appreciate your help.


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## irw (25 Dec 2022)

swee'pea99 said:


> The thing I'm not clear about at this point is what state to leave these
> 
> View attachment 670977
> 
> ...


I'm a bit late to the party I think, but jsut for clarification, assumign you're talking about the bit with the bleed key on it, these should stay fully open. If you had a zoned system, the actuators would sit on top (where you have the bleed key) and open and close as per heat demand from different areas


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