Unvented hotwater cylinder

[Softus]

You seem to be very good at interpreting things the wrong way!

It must be a gift.

I personally wouldn't call that kind of installation basic plumbing - it may well be straightforward but that is NOT the same thing!

So be it. :shrug:

WHY would I want to install a potential hotwater bomb into my own home?

I would have to guess at your motivation. Is it because the folklore about it being a "potential bomb" (sic.) applies only if it's wrongly installed?

However if I did probably the only point at which any one would realise and I could be prosecuted for having done so would be when I was scalded and homeless!

That's a bit like saying that the first time you would be discovered DUI is when you mow down another road user. The reduced probability of discovery does nothing to make the crime any less criminal.

Since you keep going on about it why have you not mentioned that is a requirement to ensure you local council is aware of the installation and that it requires building approval as well?

That's covered by the notifiable element, therefore I've already mentioned it. If you keep denying that it applies, then I'll keep correcting you. If you consider that my persistent correction of your error is "going on about it", then I make no apologies for that, because the bigger picture is that serious errors need to be pointed out to any reader who (against all odds) knows less than you do.

Surely the very question I asked indicated I was quite cautious -

can I drain and refill the cylinder myself?

If you'd prefer people to assume that your claimed caution is the same thing as knowing what's actually dangerous and actually illegal, then you're posting on the wrong forum.

If you'd prefer people to interpret your words in the way that you mean them, then you should write your words unambiguously. In this context I can't think of a more woolly term than "basic plumbing" (other than "basic work" perhaps).

 

[ChrisR]

Yes once installed you can empty and refill it as much as you like.

Even pro plumbers get the installation wrong sometimes.............

 

[Tockalex]

If you'd prefer people to assume that your claimed caution is the same thing as knowing what's actually dangerous and actually illegal, then you're posting on the wrong forum.

Hence I thanked you for providing the information that it was sepcialist installation and mainenance despite already knowing. I would still be greatful to a response to my actual query - since you have seen fit to post so many unpleasant and unhelpful commnets rather than answer the query perhaps I should assume that you know less than I do!

If you keep denying that it applies

I have never implied or denied that it applies. I would also have thought that I have made it abundantly clear that I have no intention of doing anything to the contrary. If I had presumably my query would have related to Filling the cylinder not REfilling it!

persistent correction of your error

The only error is on your behalf not actually reading the posts and then being willing to see that you could have made a mistake in your interpretation

That's a bit like saying that the first time you would be discovered DUI is when you mow down another road user. The reduced probability of discovery does nothing to make the crime any less criminal.

Again you entirely missed the point but an equally good example - the probability of discovery is, in my opinion irrlevant, the risk you are taking is the issue - why do it?

 

[Tockalex]

THANKS ChrisR that's exactly what I wanted to know.

 

[Softus]

Hence I thanked you for providing the information that it was sepcialist installation and mainenance despite already knowing. I would still be greatful to a response to my actual query - since you have seen fit to post so many unpleasant and unhelpful commnets rather than answer the query perhaps I should assume that you know less than I do!

It wasn't, and isn't, my intention to be unpleasant.

I believe that ChrisR has answered your specific remaining question.

The only error is on your behalf not actually reading the posts and then being willing to see that you could have made a mistake in your interpretation

I'm always ready to concede an error. I still don't see where I made it, but am happy to assume that I did and to hereby apologise for it.

That's a bit like saying that the first time you would be discovered DUI is when you mow down another road user. The reduced probability of discovery does nothing to make the crime any less criminal.

Again you entirely missed the point but an equally good example - the probability of discovery is, in my opinion irrlevant, the risk you are taking is the issue - why do it?

On that point, and on that rhetorical question, we are of one mind.

 

[Tockalex]

 

[BigBurner]

A heat bank thermal store can be DIY fitted and works on mains pressure. Why hasn't anyone else suggested this? Look at the Albion Mainsflow thermal store it is cheap enough and cheaper than most unvented cylinders. Be sure to fit a Magnaclean filter on the return pipe to the boiler. It will need a pressure reducer as it operates at around 3 to 3.5 bar.

There will be no plastic pipes bursting as it is not pressurised.

 

[Goldspoon]

To help answer the poster's question. Am I right in the following procedure?

>>>>>Unvented in house

To change taps (example) if you do not have iso valves...

Turn off the mains water to the house.

Turn off the electricity supply to the boiler and the unvented cylinder.

Open cold and hot taps and wait for water to stop running on both (hot water from unvented will take time to drain if it is higher than the tap). Switch other taps on and off in house in case of airlocks.

Do work (and fit iso valves).

Turn on mains water and electrics to boiler and unvented.


In the above procedure I believe there is no need to have an unvented licence. Am I correct?

 

[ChrisR]

Yes it's as simple as that. Simpler really as, assuming there's no automatic air vent (which would be unusual) this isn't an issue:

(hot water from unvented will take time to drain if it is higher than the tap)

You DO have to wait a while for the HW to drain, while the compressed air in the "bubble top" like in a Megaflo decompresses.

Thermal stores can be used and can have some advantages, and some disadvantages. They've been discussed ad vomitum, and a forum Search would be wothwhile.

 

[BigBurner]

There is no way around not having an unvented license. to install or work on.

Yes, DHW only thermal stores perform the same as unvented cylinders and can be DIYed and cost no more. The Albion Mainsflow also can have CH loop taken off the cylinder if he wants. I would advise this if it is not a big problem to do it. Otherwise the CH tappings can be plugged and it used it as a DHW thermal store. He just has to put in a minimum of three X-100 can in the system. The recovery rate with be fast as the thermal store is heated directly. There are some thermal stores available that have heating coil in them like a normal indirect cylinder.

I recently replace a vented cylinder that was leaking with a Mainsflow. The zone valves were dicky and old so I connected the CH to the cylinder, using a Wilo Smart pump using the existing pump for the boiler. It was simple as the old pump and valves were all at the cylinder position. I fitted the Magnaclean on the CH return loop. Customer delighted as I fitted TRVs on all the rads and removed the wall stat, and they had high pressure hot water which they thought was brilliant. It was a very cost effective update and they still had the old boiler.