DIY Underfloor heating manifold

[Gus Potter]

Hello all.

 

Cheepish, chearful and it seems to work! This is my "Covid temporary manifold", looks like it will be the permenant one.

 

Components: Filter, pump, 22mm manifold cut and soldered in a couple of hours, mixer valve - 28 mm reduced down to 22 mm to maintain a good flow, 15mm gate valves.

 

Does it work? - yes better than expected.

 

How did I calibrate it - flow ect - with my hand - too hot turn the valve down etc.

 

Attractions, can get all the parts off the shelf.

 

Connected to a standard heating system, combi boiler. Tapped into the flow side to the heating using close coupled tees. Still got the electrical controls to do etc, but great warm feet.

 

Mistakes..cut one of the pipes too short, pride comes before the fall!

 

Simple stupid.. yes, so pile on folks.

 

 

Edited November 2, 2020 by Gus Potter
Sorry, some photos are the wrong way up

[CC45]

good effort!

[Gus Potter]

Thanks CC45 for the encouragement, stuck my head above the parapet here.

 

 

[Gav_P]

Nice one. It’s a great feeling when you’ve done something like this yerself ?

 

Is there any reason why you have a mix of compression and solder fittings? Or was it just what you had kicking around. 
 

also how do you go about bleeding or draining it? 

[Gus Potter]

Hello Gav_P

 

Ta. Yes the solder fittings are on the manifold part as I know that they leak less if you can do a half decent job of the soldiering. To be honest once I pressurised it there were a couple of leaks in the soldering (I'm an Engineer not a pro Plumber) so it was easy to strip it down and fix the bad joints as I had put in the compression fittings. Can't rememeber the film but there is a quote something like " know you limitations"

 

The compression fittings are so that I can take it apart easily later on when the gate valves fail, get the pump out and so on. I was aiming for stuff I can get from screwfix etc to fix stuff when it goes wrong. I have some boss white...if need be, hopefully I won't need to strip down that often. Saying that I spent a bit extra on an oversize mixer valve as it's onto an old system. Just wish I had spent a bit more on maybe the lay flat UF type pipe.

 

I''ll take another photo later but on the flow side after the filter which is on the flow side I have a 15mm bottle vent valve, then on the return I have a 15mm manual air vent.

 

It's not a work of art I admit and as always on reflection you think, hey, I could have improved on that.

 

 

[ProDave]

No flow meters?  no zone actuators?

 

Not knocking it just saying it is unconventional.

[Gus Potter]

Hi Dave,

 

Thanks for piling in. I just rigged it up to get a bit of heat. Still need to finish the job. But I just thought I would wing it to get a bit of heat into the place as it's my own house. Would I spec it at work.. not that brave.  I'm more on the structures side.

 

Surprisingly to get things kicked off, I just tapped off the radiator flow side with a couple of 15mm pipes using the close coupled tee principle ( I read this on the internet and thought, I|'ll see if it works) and it works fine for a temp supply.

 

Yes, no flow meters, or fancy stuff, it's my own house so I can go "old school" and just face the fact that the UF system is a massive heat sink. Wife said I looked like a submarine commander just adjusting the gate valves, never mind flow meters. Pratically, in a few years time all these gadgets get gummed up, and few folk know how to fix this stuff, hence my Flintstone approach!

 

If part of the floor is a bit too hot I'll just put my hand on the floor, too hot, then turn it down a bit.. Ignorance is bliss.. I may come back on here later asking how do I fix my oak flooring as the UF was too hot!

 

 

 

 

[Onoff]

1 hour ago, ProDave said:

No flow meters?  no zone actuators?

 

Not knocking it just saying it is unconventional.

 

I might be dreaming but didn't you do a similar DIY manifold? 

[ProDave]

9 hours ago, Onoff said:

 

I might be dreaming but didn't you do a similar DIY manifold? 

Yes, but mine was for distribution of hot and cold water to bath and basin taps, not for UFH.

[Nickfromwales]

52 minutes ago, ProDave said:

Yes, but mine was for distribution of hot and cold water to bath and basin taps, not for UFH.

The only bit of kit needed here is the thermostatic valve, and that one is a good make and will be super-reliable. 
Flow control is simple to work out. Working from the biggest loop, open the gate valves 100%. For the next longest loop, close whatever % difference the difference is and keep going until the shortest loop is the least opened gate valve. 
Most gate valves are 13 turns so 1.3 turns = 10%. Bingo.

 

@Gus Potter you are a pipe wizard, Potter. ?‍♂️ 
 

Love the comment about the submarine commander ?. Did you put a suitable hat on whilst frantically twisting gate valves in different directions with both hands? “She’s coming up by the stern, captain!!! Somethings gone wrong” lol. 
 

Time to start a book on how long this system will be in like this for with the door shut..... ???

[Onoff]

19 minutes ago, Nickfromwales said:

The only bit of kit needed here is the thermostatic valve, and that one is a good make and will be super-reliable. 
Flow control is simple to work out. Working from the biggest loop, open the gate valves 100%. For the next longest loop, close whatever % difference the difference is and keep going until the shortest loop is the least opened gate valve. 
Most gate valves are 13 turns so 1.3 turns = 10%. Bingo.

 

@Gus Potter you are a pipe wizard, Potter. ?‍♂️ 
 

Love the comment about the submarine commander ?. Did you put a suitable hat on whilst frantically twisting gate valves in different directions with both hands? “She’s coming up by the stern, captain!!! Somethings gone wrong” lol. 
 

Time to start a book on how long this system will be in like this for with the door shut..... ???

 

So for my eventual manifold I could just copy @Gus Potter? 

 

Could I feed that set up from a low loss header? 

[ProDave]

34 minutes ago, Onoff said:

 

So for my eventual manifold I could just copy @Gus Potter? 

 

Could I feed that set up from a low loss header? 

The only thing I see missing is the individual actuator valves to turn each zone / loop on and off individually.  I would love to see a simple solution to add that to this sort of home made manifold.

[PeterW]

13 minutes ago, ProDave said:

The only thing I see missing is the individual actuator valves to turn each zone / loop on and off individually.  I would love to see a simple solution to add that to this sort of home made manifold.

You can do that with 2 port valves but tbh they aren’t really needed as unless it’s over 2 floors, the temperature differential between rooms on the same floor is negligible. 

[ProDave]

2 minutes ago, PeterW said:

You can do that with 2 port valves but tbh they aren’t really needed as unless it’s over 2 floors, the temperature differential between rooms on the same floor is negligible. 

2 port valves per zone would be an expensive sollution.

 

Even in our well insulated house, on a sunny day it is noticable how the 2 living rooms switch off early, but the north facing utility room keeps running a lot longer.  All on one zone that room might end up colder.

[Nickfromwales]

TRV’s would take a normal actuator? Available from £5 up. 

[Gus Potter]

Hi all.

 

Thanks for the positive response, much appreciated.

 

The top manifold with the gate valves is on the flow side. I stuck a 22mm compression stop end on it in case I wanted to flip it round later (made a pigs ear of it), or got a huge bit of gunk in it.

 

There are a couple of stubs pointing down from the hot manifold on top / cold side on the bottom with compression stop ends. These are so I can add another loop later.

 

The five loops you see all serve one room / open plan area. Pipes are 15mm as they are compatible with standard off the shelf kit. I kept the loops to about 50 - 75m in length so that if one fails it's not a massive disaster. Also, I can let the pump tick over so not thrashing it with the noise that comes later when it gets a bit worn. I'm pretty deaf so don't mind but wife still has good hearing!

 

I've got a temporary drain cock down at solum level for now.

 

The next step is to add in more circuits for other rooms, bathroom, hall way etc. I want to use room thermostats so can control the temp of the different areas.  I think I might make up a another manifold and start adding two port valves to these , controlled by the room stats. I'm going to get a new combi boiler that will do the hot water, feed the old rads and do the new UF part.

 

Nick - yes I think you are warning that a lot of heat will come off my DIY pipework.. yes but it's going to be in the utility room, we want a pully for drying clothes an so on. Once I box it all in if it gets too hot I'll block up some of the vent holes in the box. Got a gut feeling it will last a while with the odd bit of TLC.

 

Yes looked at a low loss header but was put off by the price.. my house is not that big compared to some of the projects on here...

 

Now to serious matters. Do I put another bank (manifold) above or somewhere else, the new boiler is to go above the filter. I think it would be a good sub commander look if you can have both arms spread, adjusting the knobs while looking at the gas flame through the small combustion port on the boiler (the periscope). One's posture may invite the vulgar here to make adverse comment though.

 

Can you make your project your own?  Have a quick glance at Yuri Gargarin in the Vostok, first man in space and so on. That craft has gate valves too. They look like the ones Screwfix used to do before B & Q bought them over. if it was good enough for Yuri then..  potential new look.

 

Watching the US election results so diving onto build hub to make a night of it!

 

Thanks Pro Dave et al for the input. It's not my area of expertise so in a lighthearted note you may want to class me as one of those folk who know just enough to be dangerous / daft

Edited November 4, 2020 by Gus Potter
Recognising Pro Dave et al

[Onoff]

Any chance of sketching out what you've done? Crayon is fine! ?

[Gus Potter]

Hi @Onoff

 

Schematic as requested, its' not a work of art I'll admit.

[Gav_P]

14 hours ago, Gus Potter said:

Hi @Onoff

 

Schematic as requested, its' not a work of art I'll admit.

You’ve got very sharp crayons ?!