Wet underfloor heating connection

[shoehorn]

Hi,
I have had an extension built with underfloor heating installed.
The area is open plan and some 64 sqaure metres. Two pipes of 100m each were used - so the manifold has two "ports".
I have a couple of questions if anyone can help please.
1. Is the 200m of pipe enough for the size of the extension?
2. The manifold is connected directly to the hot water cyllinder (a MegaFlo) - is this correct? I feel it should be connected to the boiler in the same way my radiators are, but I really have no idea.
Thanks.

 

[ShaunCorbs]

Need pictures of the connections to the cylinder etc

Was there drawings some of how to lay the ufh and heat loss ?

 

[shoehorn]

Need pictures of the connections to the cylinder etc

Was there drawings some of how to lay the ufh and heat loss ?

Sorry, I can't add pictures for question 1 because the 2 x 100m of pipework has been covered by the screed.
- it may be a bit late to ask now, but I only wanted to know if 200m of pipes is enough for 64 sqm of floor area (open plan).

And no, there were no drawings, it was white pipes that were laid (fixed with clips) on top of Cellotex... the pipies in the new part of the extension were then covered with screed, whilst the old (original) part had no screed on it beacause the floor was on beams, I think that is the name, but in essence the old part was suspended, so the pipes we're left as they were, clipped to the Cellotex, and then the chipboard floor was put on top (with the new flooring to be laid on top of the chipboard) - with no screed of any kind, just the air.

As for the manifold connection (question 2), I've been told to leave the hot water on constantly, but I haven't as this is £30 per day in gas (even when the floor was warm), so almost £1,000 per month - which does not seem to be as efficent as I have been lead to understand UFH is...

Without a picture I do understand it's not as easy to visualise, but basically, the manifold is fed from the hot water to the MegaFlo (which comes from the boiler) - so that doesn't seem right to me... but as mentioned I really have no idea, so any further thoughts/advice would be welcome - thanks.

 

[ShaunCorbs]

Nope doesn’t sound right

Should be a pug mix or sand for the timber floor and you shouldn’t have to leave hw on

 

[fowlerboi]

£30 in gas is 300kw or 12 kw/hr which is ridiculous or wrong. I've done new builds where a 35kw boiler would run flat out all day on initial heat up but would then be fine after that.

For 16mm pipe and a boiler you would normally look at 200mm centres for the pipes meaning 200m of it would do 40m2 of room.

What you describe for the feed of the manifold from the cylinder is fine. I expect you have a boiler flow go to your cylinder and then a new valve which redirects it to the manifold (this is standard) the reason you're leaving the hot water on is probably because its not been wired yet and he's left the valve open to heat the floor up. A photo of your airing cupboard would be handy.

but in essence the old part was suspended, so the pipes we're left as they were, clipped to the Cellotex, and then the chipboard floor was put on top (with the new flooring to be laid on top of the chipboard) - with no screed of any kind, just the air.

Like this?

How thick was the celotex used on the screed and joists?
How much kitchen units did they have to avoid going under?

 

[SimonG]

Sorry, I can't add pictures for question 1 because the 2 x 100m of pipework has been covered by the screed.
- it may be a bit late to ask now, but I only wanted to know if 200m of pipes is enough for 64 sqm of floor area (open plan).

And no, there were no drawings, it was white pipes that were laid (fixed with clips) on top of Cellotex... the pipies in the new part of the extension were then covered with screed, whilst the old (original) part had no screed on it beacause the floor was on beams, I think that is the name, but in essence the old part was suspended, so the pipes we're left as they were, clipped to the Cellotex, and then the chipboard floor was put on top (with the new flooring to be laid on top of the chipboard) - with no screed of any kind, just the air.

As for the manifold connection (question 2), I've been told to leave the hot water on constantly, but I haven't as this is £30 per day in gas (even when the floor was warm), so almost £1,000 per month - which does not seem to be as efficent as I have been lead to understand UFH is...

Without a picture I do understand it's not as easy to visualise, but basically, the manifold is fed from the hot water to the MegaFlo (which comes from the boiler) - so that doesn't seem right to me... but as mentioned I really have no idea, so any further thoughts/advice would be welcome - thanks.

its a real p poor install. the suspended part should have either spreader plates or a screed between celotex and timber floor.

Who laid the underfloor pipe and piped it up?

wirings all wrong as well.