Drain off leak/weep.....

[WaterTight]

Hi,

I am changing a couple of TRV's on this system. The drain off on the unvented cylinder is weeping.

Would you just tighten it up and tell them to let you know if it still weeps or once pressure is let off/vacuum achieved to change TRV's could you take out the works and change them/the washer at the same time?

I don't know how these cylinders work so wanted to check that would be a good time to do it.

Also which works/washer would I need? None of these I've linked to look quite like it

Thanks

https://www.NoLinkingToThis/c/heati...31690&page_size=20&page_start=0&sort_by=price

 

[Stigster]

Why are you draining the hot water cylinder to change TRVs? Are you G3 qualified to work on unvented?

 

[WaterTight]

Not draining, letting off pressure to create vaccum/airlock and then topping up pressure again after at filling loop. Didn't realise I needed to be G3 to do that? And if I do need to be - And if I need to be G3 to sort the drain off too - then it'll be a good job I asked!... I shall await with baited breath.

 

[Scott_D]

Is that on the cold feed or heating?

 

[WaterTight]

I realise now I was presuming it was heating without actually knowing.

So don't know is the honest answer there. Here is a photo with bit more persepctive in case that helps?

 

[Stigster]

If that's a Megaflow it appears you are looking at the cold feed to the cylinder there, not the heating side (Primary coil). That's not going to help you change the TRVs as that is not connected to the heating system.

As for how to fix the weeping drain off, it's likely to be a 3/8 inch washer you need. The innards screw all the way out (like you would do for soldering to avoid damaging the washer with heat) and the old washer just pulls off a little stem and a new one pushes on.

It's possible the old washer will stick inside the body of the drainoff so you might need to fish it out with a small screwdriver.

As for being G3 registered, you are not actually working on any of the safety devices or pipework but I will defer to others whether it is OK for you to work on that part of the system. I do not know for sure so hopefully someone with relevant knowledge will let us know.

 

[Welder]

Trace the pipe back. If it goes to the control block then it's def the supply to the cylinder in which case it's G3. If it is the case, (as I suspect) then it's also def not anything to do with heating. HTH

 

[ShaunCorbs]

I would change the washer best to drain it down

 

[WaterTight]

Hmm, I think I'll make my excuses with the drain off then in case I can't satisfy myself whether I'm allowed to do it or not. Tell them to get a G3 chap for that bit.

Thanks

 

[Scott_D]

Hmm, I think I'll make my excuses with the drain off then in case I can't satisfy myself whether I'm allowed to do it or not. Tell them to get a G3 chap for that bit.

Thanks

Do the course , It’s a day

 

[hammers4spanner]

See that blue circle as pipe enters the cylinder it should say cold feed around it.

These cylinders normally have indicators of which pipe does what

 

[king of pipes]

It is the cold water inlet the drain off is serviceable but if your not competent and comfortable carrying out the work leave it well alone . Kop

 

[WaterTight]

Do the course , It’s a day

A day to learn how to change a drain off washer? How much is it and where is a good centre?

 

[Scott_D]

A day to learn how to change a drain off washer? How much is it and where is a good centre?

The won’t teach you to suck eggs
Around £300, any training centre. I did mine at the local Vaillant centre

 

[WaterTight]

Yeah no I wasn't implying it was beneath me lol. I am one grandma who could do with a few pointers on egg sucking. I think I am likely - by a wide margin - the least trained, least experienced and least skilled person posting in the Plumbers Arms. Someone has to be!

 

[Scott_D]

Yeah no I wasn't implying it was beneath me lol. I am one grandma who could do with a few pointers on egg sucking. I think I am likely - by a wide margin - the least trained, least experienced and least skilled person posting in the Plumbers Arms. Someone has to be!

At least it’s not me
Get the book and have a read, it’s really not rocket science but in practice lots of people get it wrong or cut corners.

RE the drain off
If you buy one the same you can take it apart, see how it works then use the bits to fix the dripper

 

[WaterTight]

I thought I couldn't if I wasn't G3?......

At least one person above said so if it is the cold feed.

 

[WaterTight]

I did look to try and find the exact same drain off but none seemed to match it. But I'm happy not to touch that what's above me lowly station like.

 

[Scott_D]

Drain Cock Type A - 15mm Brass - 7490 | BES.co.uk

 

[Jim Goodenough]

Do the course , It’s a day

A day to learn how to change a drain off washer? How much is it and where is a good centre?

I did mine with Ideal for £90, centre was in Leeds.

The won’t teach you to suck eggs
Around £300, any training centre. I did mine at the local Vaillant centre

 

[Last Plumber]

I would replace the washer, clean the seating and put a little smear of silicone grease on the face of the washer.

 

[Last Plumber]

I thought I couldn't if I wasn't G3?..

That depends on your level of confidence and competence.

 

[WaterTight]

What, legally? So you can work on things like drain offs on unvented cylinders if you are 'competent' but unqualified?

The job is long gone and I didn't do it so this is just out of curiosity.

 

[Riley]

It’s the whole grey area again isn’t it. What is competent. It’s the same as gas Safe. If they just did away with the ambiguity and said if you don’t have the tickets you can’t work on the appliance then it becomes a legal recourse rather than just one person‘s opinion over another

 

[Last Plumber]

What, legally? So you can work on things like drain offs on unvented cylinders if you are 'competent' but unqualified?

The job is long gone and I didn't do it so this is just out of curiosity.

Read doc G section on workmanship here, then read App doc 7 here and The amendment to doc 7 here. Schedule 4 is here if you need to look at it

Once you have read through that you will know as much as anyone else.

My view is that as long as work is carried out in a professional and 'workman like manner', meets the requirements of all appropriate regulations and standards and notification is made as necessary to BCB's (Building control Body), then it is 'legal'.

However, notifiable work still requires notifying to the BCB and that is much easier if you are a member of a competent persons scheme. There is a lot to be said for the scheme as in effect (and in theory), you have 'proved' your competence upfront!

Ultimately, if you are repairing or maintaining anything, you are responsible for its safety. If you carry out work on an unvented cylinder - even if it is minor - I would say you are most likely to be held responsible for the safety of the cylinder following your visit. It may be possible to prove you are not responsible for any incident involving the cylinder after the fact but it could be difficult and I am sure that insurance companies will wriggle and customers will point the finger regardless of how simple the task. Although the work you carried out 'might' be legal, they will say "you are not qualified" and they would be correct. It is better in my opinion to get the qualification and join the crew. The cost involved in adding another string to your bow it is well worth it. One of the reasons we become qualified at anything is to prove our education and competence on paper. It is also true to say that someone with qualifications and experience (experience being more important in my view) would be likely to spot any issues with an installation they are working on and address them.

Thoughts?