OSO Unvented water tank - Pressure issues

[igneous]

Am sure you are quite handy. Sorry if you've hit a brick wall here but I've no idea of your level of competence. There's a bit more than a unseasoned dish at stake 😉. If you use to much force trying to undo the head, you'll have more than a potentially blocked valve to deal with.

 

[jonstatt]

The regulations (law) state that only a competent person can work on un-vented HW systems and their associated safety systems. In the HSE eyes, competence can only be asserted by individuals passing and obtaining the relevant qualifications, very similar to the rules governing gas work. Therefore if anything did happen and individuals were injured, as you don't have the qualifications, you would be criminally responsible.

I and the others are not trying to be cheeky or insult your intelligence or even having a go at your proficiency, ability or the right to learn and beter yourself, that's the rules & regulations plain and simple and therefore the law I'm afraid and what everyone else is saying!

That's a fair point and I have no issue with the way you expressed it. I found Dan's way of saying things put me in a defensive position.

The trouble is the house was built in 2006 and the CH/HW work was apparently done by people with the relevant qualifications. But I have found all sorts of things. For example, they installed a secondary hot water circulation pump but wired it up so it only came on while the hot water was heating which is pointless. As soon as the hot water got to temperature the secondary pump stopped....a simple and silly error where it was wired into the S-plan junction block and repeated over all my neighbours houses too. None of the s-plan wiring conforms to the recommended terminal block layout. There was dripping through the tundish within 3 months of moving in.

So fine, I am happy to seek a professional, but I need to find one that doesn't just have the certification, but has a track record with these cylinders and won't rip me off!

 

[jonstatt]

Am sure you are quite handy. Sorry if you've hit a brick wall here but I've no idea of your level of competence. There's a bit more than a unseasoned dish at stake 😉. If you use to much force trying to undo the head, you'll have more than a potentially blocked valve to deal with.

Indeed. I understand. Thanks for the reply.

 

[igneous]

Sorry if I came across a bit terse. Ps. Qualification is no guarantee by any means. Hopefully you will get it sorted 👍

 

[igneous]

And my cooking is rubbish 😁

 

[Madrab]

Sorry to hear that you have had a bit of a shambles. More that happy to concede that there are 'professionals' out there with the relative qualifications, that shouldn't be let near any of these key and potentially dangerous systems, it's a real scourge on our and other trade professions unfortunately.

 

[jonstatt]

And my cooking is rubbish 😁

LOL...so is mine!

 

[Dan Robinson]

I'm not too bad as it happens .

Plumbing isn't too shabby on occasion either .

 

[oilboffin]

I'd seriously listen to dan I'm registered for unvented and I've seen what can happen with well meaning people messing with what they don't know
about I was also a retained fireman and once helped to scrape the remains
of a householder off the side of half what was left of his attic after he messed with an unvented cylinder ugh

 

[vulcancontinental]

I did a lot of work in Hertfordshire and know much of the area.

Get a pro to do this BTW.

I believe you should add an external expansion vessel to the system.

I found the water in some areas, Hertdfordshire particularly, will absorb the air gap at the top of the cylinder in a matter of months.

It's also an Ovo cylinder, an advantage of which normally means (depends on the model) that you can remove the drop tube from the hot outlet and use the full capacity of the cylinder as it is then fully flooded.

I repeat, don't do this yourself.