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Homebrew UFH Test Kit?


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#1 Onoff

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Posted 08 January 2016 - 10:10 AM

I've been reading (always a bad sign :lol: ) that you can test UFH pipework using a car foot pump.....

Guess it's on the lines of fill the loop at mains pressure and top up the pressure with the pump?

YES, I know I can hire a test rig from HSS at £45.75/wk but I understand it has to stay in place whilst the slab is poured / curing. Knowing how long I take I don't want to be paying huge hire charges. Buying a rig on ebay looks an option but that's £80 I could do without spending for what might as well be a one off considering the time it'll take me to do the next room(s)!

http://www.hss.com/h...pressure-tester

So.....I have an 11 bar pressure gauge, foot pump etc.....

Any pointers?

#2 Nickfromwales

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Posted 08 January 2016 - 11:07 AM

Buy two 16x15mm straight couplers.
Make one into a 15mmx3/4" male copper to iron and connect a pressure gauge to it.
Do the same the other end but just connect a non return valve ( arrow facing in to the Ufh :D ) and then to the cold mains. Open the water supply and raise the pressure to whatever you have coming in. Disconnect water and that's the end of the chat.
It's only ever going to see 3.5bar max ( sealed system prv ) so forget all the above and have a chill out. ;)
Regards, Bob ( your uncle ).

Edit : ( if you have 16mm pipe of course ).

Edited by Nickfromwales, 08 January 2016 - 11:07 AM.


#3 Onoff

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Posted 08 January 2016 - 11:44 AM

Owe you a beer(s) as always!

Plumb Centre on the way home then!

Btw, do I have to bleed it of air?

Edited by Onoff, 08 January 2016 - 11:46 AM.


#4 Nickfromwales

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Posted 08 January 2016 - 02:18 PM

No. Pressure is pressure. If you have a problem with that short run I'll eat my hat.
;)

( brown sauce at the ready :ph34r: )

#5 SteamyTea

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Posted 08 January 2016 - 02:37 PM

View PostNickfromwales, on 08 January 2016 - 02:18 PM, said:

Pressure is pressure.
When checking pressure with air, you are putting more energy into the system. Why large pressure vessels are not checked by pumping air in. They tend to fail explosively.

#6 Nickfromwales

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Posted 08 January 2016 - 03:44 PM

View PostSteamyTea, on 08 January 2016 - 02:37 PM, said:

When checking pressure with air, you are putting more energy into the system. Why large pressure vessels are not checked by pumping air in. They tend to fail explosively.
Ok, time for another physics lesson me thinks :)
1 bar of pressure whether it's pneumatic or hydraulic is 1 bar, no?
Tin hat on and ready.

#7 SteamyTea

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Posted 08 January 2016 - 04:00 PM

It is to do with the compressibility of the fluid.
Also known as elastic energy potential.

Image you have two canisters, one filled with water at 10 bar and one filled with air at 10 bar.
Which one do you want to be next to when drilling a hole in it?

It is not the way the canister material fails, it is the energy in the escaping fluid.

Edited by SteamyTea, 08 January 2016 - 04:01 PM.


#8 Nickfromwales

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Posted 08 January 2016 - 04:16 PM

Well that's good news then ( plus you put it into Fisher Price terms so I understood it :D ).
So if Onoff goes through a pipe he'll soon know about it. :)
May be the last we ever see of him. :unsure: Ka-boom!!
Regards Nick

#9 declan52

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Posted 08 January 2016 - 04:24 PM

Elastic energy potential. That's my new thing learned today. Going to bed now as my onboard supercomputer is full up.

#10 PeterW

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Posted 08 January 2016 - 04:33 PM

View PostNickfromwales, on 08 January 2016 - 03:44 PM, said:

Ok, time for another physics lesson me thinks :)
1 bar of pressure whether it's pneumatic or hydraulic is 1 bar, no?
Tin hat on and ready.

Correct although you cannot compress water in the same way you would a gas, so the "pressure" a gauge reads is the static air pressure in the tube inside the gauge...

#11 Onoff

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Posted 08 January 2016 - 05:49 PM

View PostNickfromwales, on 08 January 2016 - 04:16 PM, said:

Well that's good news then ( plus you put it into Fisher Price terms so I understood it :D ).
So if Onoff goes through a pipe he'll soon know about it. :)
May be the last we ever see of him. :unsure: Ka-boom!!
Regards Nick

No more silly questions if that happens!

Took trips to 3 succesive "proper" plumbers merchants this afternoon to get the 16/15mm couplers. Drakes in Sevenoaks had them in the end.

Edited by Onoff, 08 January 2016 - 05:50 PM.


#12 Onoff

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Posted 17 January 2016 - 05:20 PM

With a new, out of the box Monument pressure gauge I took the pressure at the outside tap. It read 8.5 - 9 bar. Though this may appear high I guess it could be as we're very "rural" at the end of a long valley and most properties were originally farms / small holdings?

#13 jsharris

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Posted 17 January 2016 - 05:24 PM

That's right up near the safe working limit for some plastic pipe fittings. IIRC, most MDPE fittings have a max pressure rating of either 10 or 12 bar, even though the pipe is OK (IIRC) for 16 bar. Some makes of fitting have a higher rating than others, and again, IIRC, the Plasson ones are the ones with the 12 bar rating.

#14 Woodgnome

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Posted 17 January 2016 - 05:35 PM

View PostOnoff, on 08 January 2016 - 11:44 AM, said:

Owe you a beer(s) as always!

Plumb Centre on the way home then!

Btw, do I have to bleed it of air?

I bled the air from mine. I bought a pressure tester off eBay as well. You can compress air, but not water, so system needs to be full of water to get a proper test.
I put antifreeze in my test pump and pumped antifreeze into each circuit as the slab was going to be exposed during winter.

#15 PeterW

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Posted 17 January 2016 - 05:44 PM

View PostOnoff, on 17 January 2016 - 05:20 PM, said:

With a new, out of the box Monument pressure gauge I took the pressure at the outside tap. It read 8.5 - 9 bar. Though this may appear high I guess it could be as we're very "rural" at the end of a long valley and most properties were originally farms / small holdings?

I do hope you've got a pressure reducing set somewhere in the internal pipework as that is top end of any fittings capability and over twice the maximum on most cylinders..!

#16 jsharris

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Posted 17 January 2016 - 05:48 PM

View PostPeterW, on 17 January 2016 - 05:44 PM, said:

I do hope you've got a pressure reducing set somewhere in the internal pipework as that is top end of any fittings capability and over twice the maximum on most cylinders..!

Me too. If not, I have a spare 22mm one here that was only used for a short time then taken out that you can have for free. I had it to reduce the 5 bar incoming pressure on my supply to 2.5 bar (the thermal store had a limit of 3.5 bar), but I've since reduced my supply pressure to 4.5 bar (the max for the Sunamp PV) and taken out the PRV, when I took out the thermal store.

#17 Onoff

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Posted 17 January 2016 - 07:43 PM

Thanks for the offer ref the pressure reducing set (is that a PRV?). I'll get back to you on that. Doubt anything here has one already fitted as everything else plumbing wise is out of the Ark!

Main thing at the mo is just to test the bathroom Pex-Al-Pex circuit WITHOUT A MANIFOLD. Doing it as per Nick's post #2. Using these:

http://www.underfloo...x-pipe-16x12-ft

This is the pipe btw:

http://www.palconn.c...ntent/?373.html

Everything else on the "test rig" will be 15mm compression. Getting such a seemingly high pressure on the gauge threw me a bit. Soon find out!

I assume having the circuit at 8.9/9 bar whilst I concrete will be ok? Been reading to maybe reduce by 1 bar or so as the curing of the concrete will have a heating effect and increase the pressure.

Cheers

#18 joe90

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Posted 17 January 2016 - 07:57 PM

View PostWoodgnome, on 17 January 2016 - 05:35 PM, said:


I put antifreeze in my test pump and pumped antifreeze into each circuit as the slab was going to be exposed during winter.

What a good idea, I would not have thought of that. Cheers mate.

#19 Nickfromwales

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Posted 17 January 2016 - 08:33 PM

Pressurising with air will be no different. It ( dry test ) is very common on site and the pressure gauge will show a steady reading if there is no leak, regardless. Some sites you just can't afford to have water squirting out until it's found, hence the dry test. 24hrs and your good to go.
@Onoff
I'd really not pressurise to near 9 bar mate, that's WAY over the 6 that's recommended. What's the pipe rated at? It should be written on the side / wall of the pipe. Prob 10-12bar max, and that's a bit too close for comfort.
I'd do as per my earlier post, and use a gradual influx of water to get the pressure up to 3.5 - 5 bar ( like filling a combi up ) and then go no further. A leak at that point will be IMMEDIATELY apparent, trust me. :)
Regards, nick.

#20 Woodgnome

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Posted 17 January 2016 - 08:50 PM

If you are doing the UFH circuits yourself, just buy a cheap test pump, you can always sell it afterwards. You need the pipes full of water when you pour your slab. Just get the air out, get the pipework up to pressure and disconnect the pump and leave the gauge on whilst you pour. The pressure goes up quite a bit during the pour as the concrete warms the pipes. Just watch for any sudden pressure drops whilst doing the pour!