Water only Combi?

[Alterastro]

Hi all.

I have a very old (42 years!) gas water heater cylinder that is giving up the ghost. Apparently you can’t get parts any more

my first thought is to replace it with a combi type boiler but just hot water only. I have hot air heating which is fine and I can’t afford to convert the whole shebang to rads.

Does a water only combi exist? I guess it wouldn’t be called a combi but can’t find anything…
I realise most combi’ s can bypass the heating side but it seems logical that if water only ones exist, they would be cheaper?

thanks!

Nick

 

[CBW]

Hello Nick,

what is your current boiler? Yes you can get a heat only boiler which works on open vented systems or you can opt for an Intergas boiler, which allows you to set it up as a water heater only, this would also give you the option to convert to a different system, should you wish to upgrade to rads in the future.

In any case though, you may need a gas pipe size upgrade.

 

[Alterastro]

Thanks Chris
Current boiler is a AO Smith (Johnson & Starley) UPL-30. It doesn’t fire up on its own without fiddling with the knob. Cuts out ok when hot though.

Hoping it doesn’t need a pipe upgrade - it’s on the top floor (three story townhouse) and gas meter on ground floor. It’s currently 15mm pipe?

Like the thought of instant hot water - there’s only two of us and it’s pointless storing hot water all day.

 

[Captain Nemesis]

So will you want the thing to be able to supply a shower?

 

[CBW]

A quick search on your boiler tells me parts still available?

I’m not sure if it’s possible as I’ve never fitted one but you may be able to install a multipoint water heater on that supply. As I said though, failing that, most new boilers need a 22mm pipe size minimum, yours sounds like it might need 28mm. We (company I work for) have 3 storey townhouses, and they have 22mm pipe going to Combi’s.

You have 2 options: engage with a gas safe registered engineer who has experience with your existing boiler or engage in a gas safe registered engineer to inspect the job and quote for whatever is needed.

 

[Alterastro]

Yes, basically bath/shower and three sinks. That’s it, although I like a good shower.

I’ve seen some parts available but part numbers don’t match. Not sure how important that is. I have a GC number (392 731) and a manuf. number 41392 but can’t find those parts anywhere.

So multipoint sounds like what I’m after?!? Aren’t they basically water only combi’s?

that’s frustrating re the pipe size. Are all modern boilers 22mm?

 

[johnny2007]

When replacing radiators the boiler guy looped the flow and return on central heating pipes and pressurised the boiler.
Hot water was available as normal.
I don't know if this could be permanently left like that so to use the boiler only for hot water.

 

[kidgreen61]

Multipoint water heaters are available, Ariston make one.

 

[CBW]

One question I forgot to ask, does the Johnson Starley do the warm air heating as well? Would you plan to use the 2? If not you may need similar setup.

 

[Alterastro]

No, I have a separate warm air boiler on the ground floor. That’s fine so no plans to change that

 

[CBW]

Are all modern boilers 22mm?

No, Some boilers can be fed in 15mm, but gas pipe calculations need to be done to find out if that is ok, or needs upgrading. This is why I suggested engaging in a gas safe registered engineer.

 

[Captain Nemesis]

Multipoint water heaters are available, Ariston make one.

Quite a few makes out there to choose from.

Seems the first step to narrow it down is to decide what output you want - 30/40/50kW....