No overflow pipe for attic tank, and plastic pipe to heat source

D

Hello all,

We had a recommended plumber put in a new boiler for us just over a year ago. Recently we had a small leak and ended up calling a different plumber that we were able to reach at the time. During the second plumber's visit it mentioned two things to us.

One was that a plastic pipe was used as a connection to the hot water tank in-pipe. He said that as it was a heat source it should have been metal. See attached photo.

20220612_122718.jpg

The second point was that our water storage tank, where the mains supply is pumped to the attic does not have an "overflow" pipe. There is only one "in-pipe" coming from the mains supply, then an out-pipe to the hot water tank, and finally, a water pipe heading to the electric shower. Just those 3 are connected to the attic tank. The second plumber seemed surprised/shocked that this was not done and highlighted it as a more serious issue.

So I am planning to go back to the first plumber that did the installation and ask them to remedy this.

But I thought that I would check to see if the second plumber was correct? Also,what would the best way to approach them be? I take it that since it was their mistake they should correct it without payment, or would we be expected to pay at least a small fee?

Sorry but I know nothing about plumbing regulations. Thanks in advance for any advice and guidance.

standardg60

Did the first plumber install the water storage tank?

Don't see how the qualplex pipe is an issue, the cylinder isn't a heat source.

https://www.boards.ie/discussion/2057341418/qualplex-and-hot-water-cylinder

D

https://www.boards.ie/discussion/comment/119193877#Comment_119193877

Thanks for the response.

Yes, the first plumber installed the storage tank.

FishOnABike

I'd check with your new plumber what the regulations are for connections to and from the hot water cylinder.

I'm not a plumber but I have a feint memory of reading of a requirement that piping must be copper within a certain distance of its connection with the hot water cylinder.

cruizer101

My understanding is it is only the connection to the boiler that has to be metal.

And that is more because of the temperature of the connection point not the actual water temperature which the qualpex pipes can manage fine, rated up to 92 degress https://www.goodwins.ie/products/Qualpex-1-2-inch-100-metre-roll.html

Re the overflow, that seems like a **** up alright

asdfg87

This qualplex is on the return so basically the water temp be the same as in radiators so for me it would not be a problem. Technically i expect your plumber is correct. if it was on the higher pipe i would not be happy.

You should post a pic of the tanks as your plumbing looks tidy and i be surprised if the person who did this not fit overflow.

dathi

taken from partL building regulations Tgds

2.2.4.4 The hot pipes connected to hot water storage vessels, including the vent pipe and the primary flow and return to the heat exchanger, where fitted, should be insulated to the standard outlined in paragraph 2.2.4.3 above, for at least one metre from their point of connection.

the hot pipes must be insulated thats the only mention in building regs

Sierra Oscar

Are we not looking at part of the overflow pipe in the image itself, coming from presumably the top of the tank?

wilser

why is there a 3 bar prv with a 6 bar

safety valve on the system? the cylinder looks like it shouldn't be pressurised, and the heating system would never need one of these valves fitted

Sleeper12

Qualpex is fine at the bottom of the cylinder where it draws cold water. Qualpex isn't rated for the top of the cylinder where the hot water comes out. If thermostat fails the quaplex can fail.

Furze99

An overflow pipe would be very desirable. Pretty basic thing to install, hardest part would be getting it out through eaves/ fascia etc., so that it can drain in case of fault with ball cock or whatever. If there's a standoff you'd near do it yourself - fit a tank connector suited to pipe size above the normal waterline in the storage tank. I'd have to look but I think we have 3/4" pipe running over and poking out to outside. Obviously needs to be falling over it's length, so it drains by gravity. Saved us once, when something happened.

cruizer101

https://www.boards.ie/discussion/comment/119197093#Comment_119197093

https://www.nsai.ie/images/uploads/certification-agrement/IAB060067.pdf

According to the above

Qual-PEX pipe was also tested and meets the requirements of Class S service conditions specified in Tables 1 and 2 of BS 7291-1 of 12 bar at 20oC, 4 bar at 92oC, and short term overload temperatures of 114oC.

Even with a thermostat fail I can't see the pex failing in any reasonable amount of time, so long as there is still water the temperature isn't going to get above 100.

Have you any reference for where it isn't rated for top of cylinder?

The only restriction I have seen is not connected to a boiler.

asdfg87

https://www.boards.ie/discussion/comment/119195160#Comment_119195160

There is no overflow from hot water cylinder, OP is talking of overflow pipe ftom tank attic i expect, i think what he means is ine tank overflowing into the other or they are joined with a T. Nor perfect but ok as highly unlikely the two ballcocks malfunction at same time.

Sleeper12

https://www.boards.ie/discussion/comment/119197353#Comment_119197353

I wrote to their technical dept 20 years ago. Their advice was not to connect directly to the hot end of the cylinder or to a boiler. I do very little plumbing work on a cylinder. The exception to this is tapping into the hot for a Power shower. Their advice was copper off the top of the cylinder to a Tee. Top of the Tee in copper & below the Tee can be Qualpex

standardg60

https://www.boards.ie/discussion/comment/119195160#Comment_119195160

That looks more like the outlet from the condensing boiler, with the safety valve outlet from the cylinder connecting to it.

It does look like tidy work, possible the plumber just forgot about the overflow, give them a shout OP.

asdfg87

https://www.boards.ie/discussion/comment/119197681#Comment_119197681

So the boiler is sharing the hotpress?

standardg60

https://www.boards.ie/discussion/comment/119198007#Comment_119198007

I don't know where it is, there's only a pipe in the pic, what do you think it is?

asdfg87

https://www.boards.ie/discussion/comment/119198028#Comment_119198028

It looks like basin waste but who knows...

youtheman

That pipe looks like the cold water feed to the cylinder, which normally comes from the header tank (i.e. gravity fed). But it is fitted with a PRV, which I assume means that it comes directly from the mains, and not the header tank. So maybe there is no header tank, and if there is one, its for the central heating system. Very strange!.

standardg60

We might be talking about two different pipes, the qualpex one is feeding the cylinder and looks to be pressurized, so must be mains fed (combi set up?).

I was referring to the white pipe, which must be an outlet, which the prv feeds into.

John.G

The HW cylinder looks like a unvented one, if so, there will be a expansion vessel mounted nearby, probably white but may be red OR the HW cylinder itself may have a air bubble in the top to take the expansion. The cold water supply to the cylinder is via a combination valve where you have a PRV (pressure reducing valve) and a NRV (non return valve), then a expansion (safety valve) valve also known a PRV (pressure relief valve). If the cylinder is heated from cold to 60C then a 200L cylinder will expand by ~ 4L, the NRV in the combination valve will close and the cylinder pressure will rise by maybe 1bar or so, if the expansion vessel fails or the air bubble is lost in the cylinder then the pressure will rise very rapidly and the expansion valve will lift at 6bar (which is stamped on it) and 4L will be ejected to drain which that other take off should be piped to, each subsequent heat up will then eject a litre or two (assuming whole cylinder is not being heated each time) and will be ejected to drain at 6bar, you may then have water at 60C being ejected at 6bar, personally, whatever the regs state, I certainly would not be happy with that plastic pipe and would re pipe it in copper. If the expansion valve doesn't lift or isn't fitted then the cylinder which will/must have a TPR (temperature&pressure) relief valve will open at 7bar (or if the cylinder temperature rises to 95C.)

It looks like that cylinder is either supplied with mains cold water ("illegal" here) or is pumped from a storage tank in the attic, it's also possible that the mains itself is boosted with a pump (again illegally).

"The second point was that our water storage tank, where the mains supply is pumped to the attic", if this is a pumped supply then highly unlikely that there will be a tank with a ball cock, you may have the mains only supplying this tank and its then pumped?. If this tank is very small say 15L or so it may be the F&E tank for your heating system.

A few photo's would help.

youtheman

https://www.boards.ie/discussion/comment/119203546#Comment_119203546

There is a Pressure Regulating Valve and downstream of that a Pressure Relief Valve (in case the regulating valve fails). The white pipe is just the 'dump' from the relief valve and normally operates at practically zero pressure (as it should be 'open ended' at the other end.). You will only see fluid in the white pipe if the pressure regulating valve fails.

John.G

"You will only see fluid in the white pipe if the pressure regulating valve fails." OR (as its main purpose, as its termed a expansion relief valve) if the expansion vessel fails or no air bubble then pressure will rise to 6bar very rapidy on heating commencement.

D

Hi all,

Thanks for all the comments.

My point about the overflow pipe. I have checked all around the cold water tank. There is only one pipe in, the mains, and two out:

1. to the pump, which seems to feed into the expansion vessels, the boiler, and the cold water around the house.
2. to the electric shower.

asdfg87

https://www.boards.ie/discussion/comment/119212858#Comment_119212858

I asked you earlier to send pics of tanks. whan you say expansion vessel, are you talking about a smaller 20 litre tank in the attic. If yes is there an overflow fron this.

The work looks tidy so i be very surprised if no overflow.

John.G

One picture is worth a thousand words.