Changing water heating system with minimal upheaval

[Bernie]

My wife and I live in a very small flat, which we plan to sell some time but only after trying to maximise its value.

At present our source of hot water is an old boiler with an immerser, which has now packed up. (We do have a heated shower).

We don't really want to get another immerser because it's inadequate for our needs and so inefficient. However, we are both cringing at the thought of having our whole flat turned upside down to make a change.

Ideally, we want to replace the boiler with a gas heated system that gives us hot water on demand to the kitchen and bathroom. If possible, it should be suitable for running a central heating system at a later date though we don't really need it for our flat.

Would it be possible to just have the boiler ripped out and the remaining space used for a gas boiler, without all the floor boards being ripped up. The existing boiler is next to an external wall. The only other likely site would be below the bathroom window on the opposite side of the flat.

There is a link to a very rough diagram of the layout here:

advice would be greatly appreciated as we don't have any experience in such things.

[Christian McArdle]

Should be no problem. They can be a bit noisy at night, but this is much less of a problem in a 1 bed flat, as by definition a combi boiler will only be making noise when it is producing hot water for the user of that room.

It might be possible to use the bathroom, but it this will be subject to zoning issues which can sometimes be insurmountable in a small room. It might also require a tortuous gas run. By placing in the existing location, all the water pipework will be nearby and it is close to where you say gas is available. It will also require a drainage connection, but this should be obtainable from the adjacent kitchen.

Make sure you choose a condensing combi with >= 28kW. Baths will probably fill more slowly than with your existing system. However, if you replace your electric shower with a thermostatic pressure balancing mixer shower, the performance will be in a different leagure to any electric one.

Christian.

[Bernie]

Brilliant. Just the sort of information I was hoping for. Thanks.

[David Hansen]

On 23 May 2006 06:32:41 -0700 someone who may be "Bernie" wrote this:-

In a small flat a combination boiler is generally the best way of heating water and running central heating. It should be possible to have one with the heating blanked off for future use and only running the hot water part.

You will need mains water running to the boiler. Is the immersion heater inside a hot water cylinder with a small cold water tank above it? If so then a mains water pipe will run to the proposed boiler location. You may well be able to re-use the existing hot water pipework and all that you would need is a gas pipe to the bedroom.

How are the cold taps and toilet fed?

Heating domestic water is the critical part of a combination boiler. Running heating is the least demanding bit. I wouldn't skimp on the boiler capacity because of the small potential heating load, someone may spot this in a survey.

What is on the other side of the bedroom wall and how high up is it?

I would avoid the gas board. They charge about twice what others do and don't do a better job.

[John Rumm]

I would go along with what Christian said. I would also suggest you do a quick test with a bucket and a stopwatch to make sure that you have decent flow rate from you mains cold water supply (since this can be one stumbling block to getting reasonable performance froma combi boiler). If you get 20 litres/min or better then you are laughing. 15 - 20 is marginal but may be ok. Any less than that and I would think again.