Expansion vessel saga continues...

[James Dunn]

Evening all, i’m looking for advice...

Technical: I have PP150B Santon direct unvented hot water cylinder, cold water regulator at 3.5 bar and expansion vessel at 3.5bar. All the pipes are “clipped”. Information from plumber.

I’ve only just moved in to my first house, which is approx. 13 years old. I have an issue that only occurs twice a day, when the hot water comes on at 6am and 5pm if your the first person to open the hot tap there is a loud noise like a spring going off from the hot cylinder cupboard.

I had a plumber visit who put his money on it (my money really) saying it was the cold water regulator, which he replaced. School boy error i paid before checking his work and the issue is still present. I can no longer get in contact with him.

Before I get another plumber in, i wanted to do my research... i tracked down the installation manual for the cylinder and it states the expansion vessel must be installaed as a “T piece” between the cold water regulator and the hot water cylinder, however mine is installed as cold water regulator then a “T piece” to the hot cylinder and expansion vessel. Is that right?

Secondly, the guide says the pipework should all be done in 22mm copper, the majority of it is but the expansion vessel isn’t. Is that likely to cause the issue?

I will NOT be undertaking the work. I just don’t want to get taken for a ride and want to be clued up for when i do get the next plumber in.

Much appreciated for any advice.

 

[ShaunCorbs]

any pics of the installation?

 

[James Dunn]

any pics of the installation?

Hi Shaun, please see attached...

 

[999]

Use a G3 qualifed plumber who will source the issue.

 

[James Dunn]

Use a G3 qualifed plumber who will source the issue.

I certainly will, however the last plumber who said he was “certified” done the offski. I’m just looking to have an Ace in my pocket instead of standing with my trousers by my ankles. If you catch my drift...

 

[999]

You can usaully verify a G3 plumber through the gas safe website or ask the manufacturer who should be able to help with someone local.
Finding the right person is key to this and not atempting to make any alterations yourself as these units can be very dangerous if safety controls are taken out, alterated or replaced with the wrong item.

 

[Riley]

Nice having to drain down the whole cylinder if the combination valve ever needs replacing

 

[king of pipes]

Having down loaded the installation manual i think you know your cylinder is not piped correctly , the tricky bit is finding a G3 engineer to do a drain down and repipe it , go to our hompage and search for engineers in your area . Kop

 

[James Dunn]

Having down loaded the installation manual i think you know your cylinder is not piped correctly , the tricky bit is finding a G3 engineer to do a drain down and repipe it , go to our hompage and search for engineers in your area . Kop

Thanks for the reply. Being piped incorrectly, is it like to cause the banging i hear or is that another problem to add to the list?
Thanks James

 

[townfanjon]

Thanks for the reply. Being piped incorrectly, is it like to cause the banging i hear or is that another problem to add to the list?
Thanks James

Possibly , an experienced g3 guy may be able to sort the problem making some other checks

 

[Dilalio]

From your photos, there is a piece of foam lagging around the pipework to the vessel, just before the pipe clip that attaches it to the underneath of the shelf battens... I'd say that's been put that on there to try and stop the noise you're hearing. I'd get someone to open a tap at the time the noise occurs, while you stand there with your fingers on that section and see if you can feel the vibration. Then try something heavy on the shelf to see if that prevents the noise.

 

[king of pipes]

Thanks for the reply. Being piped incorrectly, is it like to cause the banging i hear or is that another problem to add to the list?
Thanks James

Quite possibly yes. The Incoming water pressure and flow need measuring before and after the combination valve i am not even sure the expansion vessel is secured to the wall when they fail they weigh a awful lot you need a good guy not a bodge it and legit . Kop

 

[chris watkins]

James, 2 questions for you.
1. Do you know where the safety valve discharge waste ends up?
2. Did this G3 qualified repair person carry out a service on the cylinder at the say time?

 

[James Dunn]

James, 2 questions for you.
1. Do you know where the safety valve discharge waste ends up?
2. Did this G3 qualified repair person carry out a service on the cylinder at the say time?

Hi Chris,
The waste dischage ends up outside of the house, the pipework has a protective cage around it. When the boiler has it’s issue there is no discharge.

When I showed the plumber the problem, at no point did he mention he would carry out a service. Does a service just check the pressures and valves?

Thanks,
James

 

[James Dunn]

Quite possibly yes. The Incoming water pressure and flow need measuring before and after the combination valve i am not even sure the expansion vessel is secured to the wall when they fail they weigh a awful lot you need a good guy not a bodge it and legit . Kop

Kop,

The expansion vessel isn’t mounted directly to the wall, it has two blocks of wood underneath it to support it. Not sure if it was done by the original house builders or the previous owner had someone in to do some work.

Bodge it and leg it has bitten me once, never again. I’ll be going through the gas safe register and seeing who has the G3 credentials and get a quote for the work.

Thanks,

James

 

[chris watkins]

You need to keep a close eye on the outside discharge point as the pressure relief doesn't run through your tun-dish, any signs of water coming out or on the end of a finger inserted & it is time for a service.

A service is a service & anyone who properly understood these systems would carry one out as a matter of course even if they effected a repair like replacing the valve set.

As with a lot of these things there is a difference between a G3 installer & a G3 repairer.
Find someone who can service it.

 

[steadyon]

1. G3 qualified people do not have to register with Gas Safe, although many do. There are other registration bodies.
2. Looks to me as if the expansion vessel is resting on two wooden bearers, in turn resting on the airing cupboard shelves. It does not appear to be fastened to anything substantial.
3. Might be worth investigating if the whole vessel is lifting when the pressure goes up (water heating goes on) and then dropping when pressure is released as a hot tap is opened.
4. Whatever the cause, the cure must be applied by a G3 qualified person.

 

[Best]

D1 pipe from pressure relief should be teed into above tundish.
But combination valve has to be higher as D1 has to constantly fall.
Your installer maybe wasn’t experienced in unvented install and definitely hasn’t bothered adhering to D1 regs.
Get a G3 qualified person to give you their opinion (this might prove they know their job) and if they give correct answers, then get a quote for repiping the cylinder and fixing the expansion vessel with strong supports

 

[SimonG]

G3 and gas safe are not exclusive. A g3 qualified engineer may be part of another competent person scheme.

 

[chris watkins]

Also, I hold the G3 hot water qualification but just repair the unvented systems.
I am not a member of a competent persons scheme as I do not need to notify new installations.

 

[Best]

I am same as the above posts, I have the unvented qualification but not as part of gas or other qualifications