Twin combi boilers to replace vented cylinder

[john999uk]

I am not a plumber so just looking advice before I get a plumber in to do some work.

I have holiday apartments in Blackpool and the hot water for the sinks comes from a vented copper cylinder heated by an immersion heater!!! All apartments have electric showers so it is only hot water to the sinks I need to provide.
I have 2 identical combi boliers (WORCESTER-BOSCH 24i RSF ) next to each other that provide the central heating to the whole building. They have never been connected up to provide instant hot water.

I was wondering about effectively having the copper cylinder removed and the combi boilers hot water outlets connected to the existing outlet from the copper tank. I guess that each boiler would need a 1 way valve in it's outlet so 1 boiler could not feed the other boiler.

Am I mad in thinking that I can have the 2 combi boilers hot water outlets linked to the old hot water outlet of the copper tank and that provide hot water to the building or am I missing something?

Thanks for any help you can give.

 

[Howsie]

Welcome along.

Ideally you'll need to separate the hot outputs from each combi, perhaps feeding half the apartments each. You don't want both combis trying to fulfill demand from a single tap.

 

[Whyme]

they probablly left the cylinder in to cope with demand. combis are very localised hw ie every outlet needs to be close to the boiler or theres lag meaning loads of cold before the hot arrives...

 

[john999uk]

Welcome along.

Ideally you'll need to separate the hot outputs from each combi, perhaps feeding half the apartments each. You don't want both combis trying to fulfill demand from a single tap.

Thanks.
It would be difficult to split the apartments as tracing the pipework is very difficult. Just had that fun with getting the electrics sorted for EICR.
That is why I guessed at the 1 way valves in the hw outlets.

 

[john999uk]

they probablly left the cylinder in to cope with demand. combis are very localised hw ie every outlet needs to be close to the boiler or theres lag meaning loads of cold before the hot arrives...

Thanks. You are probably right. The boilers are on ground floor and there are 2 floors above. So some taps a long way away from combi's.

 

[john999uk]

Looks like best bet is just to get a 3 port valve (+control gear) fitted to 1 boilers central heating pipes and use that to heat the indirect coil in the copper tank.
At least that way water will be heated by gas not electricity might help to keep bills down a bit.

Does that sound sensible?

Thanks

 

[Whyme]

From youre description that sounds ok...as long as the cylindrs indirect .

 

[john999uk]

From youre description that sounds ok...as long as the cylindrs indirect .

Yes it is indirect. The pipe work is already attached and blanked off to the copper tank. The indirect coil needs pressure testing before use I guess.
The boilers are only about 10 foot away from the cylinder, so should be easy to go under floor (good crawl space) to the cylinder.

Thanks.

 

[Masood]

Personally, as you're a B&B I'd put in two 3-port valves and two 2-channel controllers, so you have hot water even if one boiler stops working. The additional outlay will be quite small, and you'll get that back in savings on your electricity bills.

 

[Dotty]

We have plenty of boys round your neck of the woods. Post a thread up here - [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL] - and they may come and take a look.