TerryE

Another DHW / DCW / UFH design

Recommended Posts

9 minutes ago, JSHarris said:

If you have an old lathe centre knocking around, then I found that warming that up and pushing the cone into the end of the UFH pipe flared the end just enough to slide over the O rings on the fitting without snagging.  If you don't flare the cut ends of the pipe slightly you risk damaging the very thin O rings.  Ask me how I know this........................

I'm a little more 'rough and ready' :/. I use my Bahco Spanner with the jaws wide apart, and push one jaw into the open end of the pipe. A quick 1/2 turn left, and another to the right, and it gives a perfect chamfer to the internal bore so, as Jeremy rightly says, it doesn't damage the seals on the fittings or inserts. 

A bit of silicone lube is advised, and can make this a bit less precarious a job for the uninitiated ;)

  • Like 2

Share this post


Link to post
Share on other sites

After the first one seemed a bit tight to push on I used a countersinking bit in the cordless drill to give a little lead chamfer on my Pex-Al-Pex pipes.

Share this post


Link to post
Share on other sites
5 hours ago, Onoff said:

After the first one seemed a bit tight to push on I used a countersinking bit in the cordless drill to give a little lead chamfer on my Pex-Al-Pex pipes.

The second seal resides very close to the mouth of the pipe. ;). Be wary that you only put the absolute slightest of chamfers or you risk that second seal not fully compressing and seating as it should. 

I would advise against power tools for this as 'over-reaming' would be detrimental. 

Share this post


Link to post
Share on other sites
17 minutes ago, Nickfromwales said:

The second seal resides very close to the mouth of the pipe. ;). Be wary that you only put the absolute slightest of chamfers or you risk that second seal not fully compressing and seating as it should. 

I would advise against power tools for this as 'over-reaming' would be detrimental. 

 

I barely touched him m'lud! :) 

 

 

Share this post


Link to post
Share on other sites

The proper tool is only a fiver, so compared to everything else I am buying, its pissing in the wind not to.

Share this post


Link to post
Share on other sites
28 minutes ago, TerryE said:

The proper tool is only a fiver, so compared to everything else I am buying, its pissing in the wind not to.

 

I agree, in my case it was not knowing about the tool, and discovering the hard way that the sharp edge of a freshly cut UFH pipe tears the O rings! 

The O rings are pretty thin, IIRC around 1mm to 1.5mm ring thickness, so easy to damage.  Luckily I had a couple of boxes of assorted O rings to hand, with some the right size to replace the damaged ones.

 

I had a lathe centre to hand and found it did a perfect job of just putting a very tiny flare inside the pipe.  I think I'd have just bought the proper tool had I known in advance about the potential to damage the seals.

Share this post


Link to post
Share on other sites

Yup, the Wundatrade people have a series of excellent YouTube videos which explain how to intall their UFH manifolds and I only picked up about this by watching them.

  • Like 1

Share this post


Link to post
Share on other sites

The UFH manifolds in and pressure tested.  It's coming along. :)  Next step to plumb in my Willis heater.  

IMG_20170224_170834385.thumb.jpg.50662eaeef3c35f9e75a35cc995e7b63.jpg

 

@jamiehamy Is this one next?

  • Like 1

Share this post


Link to post
Share on other sites

Only advice to add to this phase is to add one or two automatic air vents ( bottle vents ) instead of the manual ones.

Will make commissioning a much easier job :)

These will screw straight into the empty holes ?

  • Like 2

Share this post


Link to post
Share on other sites
13 hours ago, TerryE said:

The UFH manifolds in and pressure tested.  It's coming along. :)  Next step to plumb in my Willis heater.  

IMG_20170224_170834385.thumb.jpg.50662eaeef3c35f9e75a35cc995e7b63.jpg

 

@jamiehamy Is this one next?

 

Newbie to UFH question time :) ......

 

I assume the yellow pipes and rig to the right are your temporary filling loop?

Are the hot and cold valves your currently connected to for filling and the ones to the left (under the pump) for your eventual heating connection? 

Share this post


Link to post
Share on other sites

@Barney12, yes on both accounts. Have a look at the Wunda videos on YouTube. The only difference is that I didn't buy the Wunda pressure test kit, because I already had my home brew one.

  • Like 1

Share this post


Link to post
Share on other sites
50 minutes ago, TerryE said:

@Barney12, yes on both accounts. Have a look at the Wunda videos on YouTube. The only difference is that I didn't buy the Wunda pressure test kit, because I already had my home brew one.

 

Ta. Just watched them. Very informative.

Share this post


Link to post
Share on other sites

One thing that did surprise me was that I did a flow test (after I had purged the circuits individually) by opening all three circuits and letting the mains 3 bar run from the filler though the loops in parallel and out into a bucket.  It was quite slow.  I think that this is time for a properly measured flow and some Boffin's Corner flow calcs :)

 

And thanks for the hint about the air exhaust vent, Nick

 

 

Share this post


Link to post
Share on other sites

Also note my mounting the manifold on a mounting board. I did this partly because there's only OSB behind this, but if also proved very useful for another reason. MBC use PexAlPex UFH pipe which is a lot more rigid then the stuff Wunda supply and the tails only came up 60cm or so our of the floor.  It would have been really fiddly trying to manoeuvring them into position with the manifold fixer, so I put the board in place, measured and marked the correct tail lengths, then took the board away again. I then cuts the tails to length, chamfered and fitted the insert fittings, before lowering the board into place and over the tails. I then screwed up the tails, and finally screwed the board back to the partition wall.  This worked well and was painless.

  • Like 1

Share this post


Link to post
Share on other sites

I can't remember exactly what the flow rates are on our UFH, but have a feeling they are only around 2 litres/min or so, per circuit, so around 6 litres/min for all three parallel loops.  All those bends, plus the long length of pipe, does introduce a lot of resistance to flow.

Share this post


Link to post
Share on other sites
On 11/02/2017 at 16:29, JSHarris said:

What you want as a water heater is a 3kW immersion in a tube.  They are an Irish thing, invented by a chap years ago over there, to go on the side of a conventional tank that doesn't have an immersion heater port.  They are known as Willis heaters, see here: https://www.stevensonplumbing.co.uk/willis-complete-3kw.html

We used to call them Belfast heaters, or J heaters by some, (no idea why),

Very very common, used to still get fitted in some new builds even in the '80s and '90s,!!! 

 

 

But, not technically Irish. ;)

 

Share this post


Link to post
Share on other sites

We used them on our spa bath installations.  Could get then up to 9 kW.

 

Is it called a Willis Heater after Willis Carrier, the heat pump man.

Share this post


Link to post
Share on other sites
30 minutes ago, SteamyTea said:

We used them on our spa bath installations.  Could get then up to 9 kW.

 

Is it called a Willis Heater after Willis Carrier, the heat pump man.

 

 

This Willis heater was the invention of a Belfast plumber, a few decades ago, which is why you'l find them all over Ireland but they are relatively unusual here.  The company is still going: http://willis-heating.com/

Share this post


Link to post
Share on other sites

My latest whoops is on the SunAmps.  See photo below.  (The two tails on valves are for pressure testing. and the red/blue handles are on the wrong valves.) 

 

I had carefully made up rigid tails to allow me to mount the two SunAmps side-by-side.  There are four pipe connections all arranged vertically on the back: the cold in, the hot out and two overflows for the PRelV and the cells.  So I laid it all out: cold from the bottom, hot out of the top, the two overflows off to the side and down to a tundiish.  Great. 

 

Except that when I came to connect them, I realised that the cold was on the top and the hot on the bottom -- and of course they are vertically aligned.  Given that the cold normally rises and the hot often goes up to a manifold, then they could have at least swapped them or even offset the access holes.  But neatness trumps functionality.  Thank-you SunAmp.  Now I've got to remake all of the bloody tails so they can neatly cross over.  Shit, shit, shit.   

 

Before SunAmp-back.thumb.jpg.1ef1730579d6c6959eb5b67fa3d3bca2.jpg  and after  SunAmp-back2.thumb.jpg.8e8cd9756cccd36d4fdad711286be810.jpg and pressure test SunAmp-PressureTest.thumb.jpg.45e45072368edbecf7e03e4bad56cf96.jpg

 

I know the levers are upside down, but if I turn the valves around so that they are the other way up, then they'll jam against the back wall.

 

Oh, yes and a codicil to the leaded vs lead-free solder debate.  I am using the lead-free solder for our potted water after all.  Once I got used to it, I find that I prefer it.  It seems to wet / wick better than my old lead alloy solder.

Edited by TerryE
Add 5 bar pressure test after flush though

Share this post


Link to post
Share on other sites
8 hours ago, TerryE said:

Oh, yes and a codicil to the leaded vs lead-free solder debate.  I am using the lead-free solder for our potted water after all.  Once I got used to it, I find that I prefer it.  It seems to wet / wick better than my old lead alloy solder.

Yup, that's what I found. I also like the fact that it seems to harbour less surface crud, so the joints need less cleaning / refluxing during soldering. :) 

Im a convert now, but remember to have a clean pipe and a clean fitting so soldering goes well.  What flux are you using ?

Share this post


Link to post
Share on other sites
10 hours ago, Nickfromwales said:

What flux are you using ?

 

I know that you told me to use a mild flux and not a self cleaning flux one, but I've only got a pot of Laco, so I clean off the pipe ends and fitting with plumbing wire wool and a fine smear of flux then only use a tiny amount of flux on the burnished surfaces and on the solder itself. It flows and wicks fine.  I then wash out the part before testing.

 

Share this post


Link to post
Share on other sites
42 minutes ago, TerryE said:

I then wash out the part before testing.

Flushing that laco residue out is paramount as it's horrible stuff. You REALLY should get some Telux and try it. On new stuff it's brilliant and leaves very little residue. 

Share this post


Link to post
Share on other sites
13 minutes ago, Nickfromwales said:

You REALLY should get some Telux and try it.

 

OK, but none of Screwfix, Toolstation, Plumbase, Plumb Centre, B&Q stock it.  So it would be a Q of getting some by post and putting my work on hold until Wed next week, say :(

Share this post


Link to post
Share on other sites

Do you have a City Plumbing?

 

This recommendation is for an ideal world btw ¬¬ understandable that you need to get on ;)

Share this post


Link to post
Share on other sites

Yes, but they only sell Laco and Fernox Powerflow Flux (which Screwfix also sells, BTW).  So I guess its a case of just washing out.  And talking of working, I'd better get on, otherwise I'll be getting a slap on the botty.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now