Is this horizontal Tank Installation correct?

[endecotp]

Would you mind listing the deviations you saw

I’m looking at this document; it’s not entirely clear if it’s the right one:

https://ukcylinders.co.uk/wp-content/uploads/2024/06/UK-Cylinders-Indirect-Horizontal-External-Expansion-Manual-V1-2024.pdf

Hmm, it seems I can’t copy-and-paste from it but here are some approx quotes and other notes. (To re-iterate, I’m no expert.)

“The orientation of the cylinder must have all key connections …. uppermost”

“Connection to expansion vessel” (pointing to a port on the inlet monobloc that is not used on yours)

“Mount the expansion vessel … above the cylinder”

Your balanced cold connection is not used (do you have a pressure reducing valve on the cold supply elsewhere?)

I cannot see a tundish. Where does the pressure relief pipe go?

 

[baldbob]

G3 registered = Registered under G3 of the building regulations Part G

MI = Manufacturers Instructions

UV = Unvented

Thanks CountryFan!

 

[Razor900]

First things first turn both thermostats down by a quarter turn and let the cylinder come down to temp with normal use over a day before checking whether the water is still hot enough for you.

That's a crap install and you definitely need to get someone who knows what they are doing to look at it but you don't need a cylinder full of scalding water at the top of the house with potentially incorrect discharge pipework so do the stats first please

 

[Johntheo5]

Thanks John, all updated in the original post - hopefully that helps!?

That very strange orientation will probably affect the immersion/stats as the elements are designed to be horizontal, since you are familiar with electrics it should be very easy to check with a multimeter if/when the stats are switching, even turning them up/down should result in a audible click, I though I saw somewhere the cylinder test pressure was carried out in 2006 but can;t see it now, you'r expansion vessel date of 2025 suggests its a pretty new install, so maybe only behaving like this since the mains temperature has risen in the past few weeks??, still, a compromise stat(s) settings should prevent the T&PRV lifting at a presumed 95C, those simple tests should tell you if the stats are OK.

 

[Razor900]

I though I saw somewhere the cylinder test pressure was carried out in 2006 but can;t see it now

The cylinder was manufactured in December 2025 according to the label

 

[Madrab]

+1 re water too hot - get the stats turned down, looks like they could be set to max.

I think the trouble here is that the Manu Instruction for the unit seems to be elusive - under the model WWAH250L - there doesn't seem to be much apart from a world heating reference. You should have been given the manual for it? Can you post a pic of the front page, does it have the manufacturers name and model of the unit?

As others have said, that does not look like a good install, it doesn't appear to adhere to some of the norms that other horizontal cylinders would normally follow.

The installer needs to confirm that they are G3 (HWSS) certified, that the install has been benchmarked, notified to the Local Authority and registered with the manufacturer. I'd certainly get looking for a qualified and recommended engineer that is familiar with horizontal installs. OI hate them, always give problems. I don't install them, rather 2 smaller horizontal units fitted in tandem.

 

[denso13]

Missed this post when replying to your other. I'm afraid I don't know what a G3, MI or UV are

The installer should be a member of a competent persons scheme, if not then a building warrant application should be made. Either way, your Local Authority Building Control should have a record of it. You could try there.

 

[baldbob]

First things first turn both thermostats down by a quarter turn and let the cylinder come down to temp with normal use over a day before checking whether the water is still hot enough for you.

That's a crap install and you definitely need to get someone who knows what they are doing to look at it but you don't need a cylinder full of scalding water at the top of the house with potentially incorrect discharge pipework so do the stats first please

Thanks Razor900, as soon as this happened I turned them both off just to be sure and drew off some of the hot water (got kids in the house, didn't want to risk anything).

 

[polesapart]

"To reach World Heat Cylinders (manufacturers of unvented hot water systems) for technical support, sales, or spares, you can call them on 0161 343 8610"* (AI result)

I think your installer has stuffed it and seriously doubt that he holds the mandatory G3 qualification.

*EDIT THIS THE WRONG PHONE NUMBER, PLEASE IGNORE*

 

[denso13]

mandatory G3 qualification

That isn't stated anywhere in the building regs.

 

[polesapart]

^^
https://assets.publishing.service.gov.uk/media/66f6c6ce3b919067bb4828cc/ADG_with_2024_amendments.pdf sections 3.40, 3.41 , 3.42

OK, I'll amend my post to stating that G3 qualification (and scheme membership) is required to notify under one of self-certify schemes.

Other route is as section 3.41

 

[denso13]

Not G3 qualification, only scheme membership which can mean no qualifications. Or no scheme membership which means a building regs application and LABC sign off.

I just see the "illegal" thing mentioned quite a bit.

 

[Johntheo5]

While probably not related to this water hammer problem I wonder would it help if the cylinder was drained down and refilled with a HW tap opened.

 

[polesapart]

OP

The manufacturers' installation instructions will give the answer to the issue of the correct orientation of the tappings.

I'd be surprised if they did not specify tappings uppermost on a horizontal unvented.