Unvented cylinder inspection

[Plumb Tidy]

Hi Lads/lasses just wanted some advice on unvented cylinder inspection. I just took on what seems to be a contract for a block of flats all with direct heating via immersion. The way they have been installed seems a bit off as there is no check valve on the supply to the cylinder. It goes,
Stop tap
Double Check valve
PRV
then tee's off to the cylinder feed and cold water supply for the rest of the apartment.
When draining i noticed if i opened up a cold tap downstairs and opened the TPRV hot water came out the cold tap.
I explained to the customer what's going on and she said she has noticed she has to draw off a bit of hot water out the cold tap before filling a glass of water and thought it was normal.
The cylinders haver been installed in 2004 was the water regs different then? as they didn't require a DCV?
Can i carry out a cylinder safety inspection in this current state?
I have only been doing unvented for around 6 months now so I'm still getting to grips with the certs. I have a picture but my phone won't upload as of yet.

 

[Scott_D]

What brand?
Are any manufacturers instructions available?

 

[Plumb-tidy]

No manufacturers instructions, around 250 odd apartments I have been to two so far today which are the same

 

[Ricky]

Hi Lads/lasses just wanted some advice on unvented cylinder inspection. I just took on what seems to be a contract for a block of flats all with direct heating via immersion. The way they have been installed seems a bit off as there is no check valve on the supply to the cylinder. It goes,
Stop tap
Double Check valve
PRV
then tee's off to the cylinder feed and cold water supply for the rest of the apartment.
When draining i noticed if i opened up a cold tap downstairs and opened the TPRV hot water came out the cold tap.
I explained to the customer what's going on and she said she has noticed she has to draw off a bit of hot water out the cold tap before filling a glass of water and thought it was normal.
The cylinders haver been installed in 2004 was the water regs different then? as they didn't require a DCV?
Can i carry out a cylinder safety inspection in this current state?
I have only been doing unvented for around 6 months now so I'm still getting to grips with the certs. I have a picture but my phone won't upload as of yet.

You cannot put a valve between cylinder and one of the pressure releif valves, and yes the way it is configured the water will syphon down cold if the supply to cylinderis isolated and you open TPRV.

 

[Plumb Tidy]

Cheers Ricky. Its an Albion stainless steel no fitting instructions and none on the web to be found. So as it breaches water regs because its allowing hot water to mix with potable water, legionella and all that i guess i cannot sign off the inspection report. I just wanted to know if the regs changed from 2004 till now because it looks like 250 apartments are piped up wrong?

 

[Plumb Tidy]

You can see the gate valve at the bottom of the cylinder feed a pipe goes through the floor. this is the cold feed to the kitchen and bathroom

 

[Plumb Tidy]

So when expansion is taking place it expands into the cold and then into the expansion relief valve as the expansion vessel was flat as a pancake and has not had a service since it was installed.

 

[Plumb Tidy]

Ok i got hold of kingspan that bought Albion cylinders so thanks Scott D for the hint. They have been plumbed up incorrectly as they should have a on return valve protecting the cold feed to the apartment even back in 2004. I ow have the pleasure of changing around 200+ cylinders

 

[ShaunCorbs]

I would think it’s acceptable as it’s not really different than installing the inlet block on the cold water mains and having the cylinder upstairs in the airing cupboard

you might have a check valve passing on a tap or shower ?

 

[Scott_D]

Is there an expansion vessel fitted?

 

[Plumb Tidy]

Yes there is a expansion vessel fitted its not doing much though,
Whats happening is as the cylinder heats up the expansion is taking place down the cold main to the kitchen tap as there is no non return valve!

 

[Scott_D]

Is it on the hot outlet?
I cant see it in your picture

 

[Ben-gee]

Why are you proposing changing the cylinders rather than just adding a non- return valve?

 

[Plumb Tidy]

It is screwed to the top of the cylinder

 

[Plumb Tidy]

Why are you proposing changing the cylinders rather than just adding a non- return valve?

Sorry just to clarify, Im not changing the cylinders, just the pipework, although they have been neglected since 2004! My original question was would this issue need to be rectified before a safety inspection is signed off as im not sure if its water regs or unvented related.

 

[John.g]

It is screwed to the top of the cylinder

The top of the cylinder is normally the hot water outlet, it seems a strange place for a E.vessel if you are referring to this, if it is screwed to the cylinder top where is the HW drawn off?.

 

[Plumb Tidy]

The top of the cylinder is normally the hot water outlet, it seems a strange place for a E.vessel if you are referring to this, if it is screwed to the cylinder top where is the HW drawn off?.

Sorry i couldn't flip the image but yes the expansion sits on the top which is incredible unstable when trying to re charge it.

 

[John.g]

The attached gives some idea of pipework which may be of some little use even though for a different type.

 

[Plumb Tidy]

The attached gives some idea of pipework which may be of some little use even though for a different type.

Cheers John G, this is the ultrasteel which is what kingspan and albion manufactured when they merged. Same rules apply the non return valve after the cold connection to protect it by ensuring expansion takes place in the vessel and not in the cold water supply to taps. Thanks all i have enough evidence to justify my work on all the cylinders.Shame they wasn't fitted properly ut then again thats where half my work comes from.

 

[Ricky]

Interesting way of installing the cylinder,
Have they sent you the orignal fitting instructions?
Why would you put the pressure gauge before the pressure reducing valve, it doesn't tell you anything helpful, ie is the pressure reducing valve shutting off at correct pressure.
Most cylinders have multiblock inlet valves, where you take the cold supply from, did some plumber fit what he thought was correct?
As Scott asked where is the expansion tank connected, I have always installed the expansion vessel on the inlet, again its to do with Legionella etc you don't want that amount of possible stagnant water on the outlet where it can get warmed up.

 

[Plumb Tidy]

Interesting way of installing the cylinder,
Have they sent you the orignal fitting instructions?
Why would you put the pressure gauge before the pressure reducing valve, it doesn't tell you anything helpful, ie is the pressure reducing valve shutting off at correct pressure.
Most cylinders have multiblock inlet valves, where you take the cold supply from, did some plumber fit what he thought was correct?
As Scott asked where is the expansion tank connected, I have always installed the expansion vessel on the inlet, again its to do with Legionella etc you don't want that amount of possible stagnant water on the outlet where it can get warmed up.

Yeah thats it, its to great having the expansion vessel o the to of the cylinder but it is subject to legionella killing temperatures. I guess thats why they have changed the design now on the ultra steels and started making valve blocks so people cannot finesse there way through an install. I have the manufacturers instructions and it has to been installed properly. As you mentioned why would the pressure gauge be before the PRV this is telling you your supply pressure to the house but not the cylinder, maybe worth moving this swell if i want to get fussy.