Replace vented direct cylinder with unvented, safety drain off?

[Bignose2]

Hi,

Small flat, currently has a small'ish feed water tank, top of a cupboard, feed through a wall into under stairs cupboard.

Hot water tank with top & bottom immersion heaters & controller.

Has a pump currently, noisy but sure normal, just seems to echo despite best efforts to supress, mats & even in an enclosure (really upsets upstairs neighbours). v.small head so some sort of pump required, I am looking into one of those small inline pumps but talk seems to be they are relatively noisy & have vibration.

So considering option to replace with a unvented system. Quite like to modernize, better natural pressure & also gain some space getting rid of tank (small flat, every little helps)

From what I can see this would be an very easy swap out for a plumber apart from the safety relief, tundish etc.
Is it likely that the feed tank will have the necessary (regulation) pipework that could be used?
Making a few assumptions ..
1) The feed tank has an overflow somewhere,
2) This pipe work would be designed for hot water, not sure about 90 degree's or whatever but in theory if the immersion heaters failed could they boil the water. (I know a gas CH can boil & steam a header tank)

However this cannot flow down from the unvented tank as of course the feeder is above.

Is there an alternative so that the pressure relief valve can go upwards (without a tundish) & into either existing tank or a smaller new tank (at least gain some space) assuming has a drain off as 1)

I believe needs to be visible or made aware of a over pressure, a drip into a tank into the cupboard (next to the bedroom) would be very obvious.

Likes a full bath from time to time so not a small tank but equally want to keep costs down & not heat lots of water unnecessarily.
Guessing 120L but can work that out later

Need to check mains water pressure but fairly sure plenty for this.

Has electric shower that assume has its own pump as does not run the main pump when being used.
So just for running a bath & sinks etc.

Electrics only, no gas.

All pretty accessible & sure enough space expansion tank etc. so would hope install relatively quite easy but after getting a few v.loose quotes, min of £2k, with a £750 tank seems to be over £1300 for an easy days work from what I have seen on YouTube plenty of times.
I know you're paying for qualification & experience etc. but seems excessive, do appreciate won't want to under quote if they don't know exactly & if is a nightmare to run an drain pipe outside somehow but fairly sure won't reduce the quote.

 

[davesparks]

From what I can see this would be an very easy swap out for a plumber apart from the safety relief, tundish etc.
Is it likely that the feed tank will have the necessary (regulation) pipework that could be used?

No the tank won't have the necessary pipework that could be repurposed for the discharge.
The overflow for the tank will not be rated for the temperature, not terminate correctly outside, likely not be big enough and be too high to allow it to drain by gravity.

Is there an alternative so that the pressure relief valve can go upwards (without a tundish) & into either existing tank or a smaller new tank (at least gain some space) assuming has a drain off as 1)

No it can't be discharged into a tank, it needs to go outside, or in some circumstances I believe it could be routed into a drain, but that needs to be assessed by a competent person.

If/when the safety valve releases the water comes out of it at high temperature and high pressure, it would rapidly fill and overflow any small tank you install to collect it.
You don't get a small drip from the discharge, you get a lot of very hot water flowing very quickly.

Has electric shower that assume has its own pump as does not run the main pump when being used

It's probably electrically heated and uses a cold mains feed only.

an easy days work from what I have seen on YouTube plenty of times.
I know you're paying for qualification & experience etc. but seems excessive,

If the people on YouTube can do it cheaper why not get them to come and do it?

 

[Bignose2]

Hi,

Thank you for your prompt & detailed reply.

Looks like a no go as cannot see a way to feed out side.

The youtube's I was referring to was watching the work being done by a few different & very well known YouTubers, well qualified & experienced plumbers & it was clearly done easily in a day on multiple occasions.

Of course you are entitled to think £1300+ for a comfortable days work is reasonable.
I would quite like to be on nearly £8K per week.
I guess more than that as sure a healthy discount on the tank & I understand they come with pretty much everything you need but perhaps a fair bit of pipe work.

 

[snowhead]

Have any of those quoting actually said the work in your property will only take a day?

Post your text on the sister site, for real life none Youtube answers,, Plumbing Forum | Plumbing Advice - https://www.plumbersforums.net/forums/plumbing-forum-plumbing-advice.15/

So from the "Easy" £1300 for a day's work,

Deduct,
VAT.
Time spent quoting and organising materials, invoicing etc.
All the usual costs of running a business, vehicle costs, insurance, accountancy charges etc.
Costs of membership to schemes, to enable notification to Building Control of the installation of an unvented cylinder.
Cost of disposal of waste materials including waste carrier registration.
Warranty cover of materials used.
etc, etc,


Looks like a no go as cannot see a way to feed out side.

Unless you you have the experience of installing unvented systems, you probably won't see how.

 

[davesparks]

The youtube's I was referring to was watching the work being done by a few different & very well known YouTubers, well qualified & experienced plumbers & it was clearly done easily in a day on multiple occasions.

You are aware that videos on YouTube are staged, edited and rarely reflect the real world aren't you?

Of course you are entitled to think £1300+ for a comfortable days work is reasonable.
I would quite like to be on nearly £8K per week.
I guess more than that as sure a healthy discount on the tank & I understand they come with pretty much everything you need but perhaps a fair bit of pipe work.

You say it is a comfortable day's work but also say it will be very difficult to get the necessary discharge pipework installed, this seems contradictory.

I doubt that anyone is expecting to make £1300 for a day of work, there's probably more to it than you are aware of, and if it's a rough estimate they will have gone high anyway as it's far better to reduce the actual bill than go over an estimate.

Plus if you have come across as being the kind of customer who will complain about the price/want to reuse old parts/do a bit themselves then they may well have put in a high price to put you off using them.

 

[brianmoooore]

By the time you've dealt with isolator valves that won't shut off and drain valves that won't open, half a day will be gone before you've removed the existing cylinder.