Boiler in the attic is a pain

[joddle]

In out semi, there is almost nowhere to wall-mount a gas boiler. The old central heating was by back boiler in fireplace in the dining room but when we had a conservatory fitted, the ventilation issue became a problem and as the boiler was over 30 years old, we opted for a new one. The plumber suggested as he could not find a decent wall to mount a new boiler where a balanced flue could easily be connected, we should consider putting the boiler in the loft. At the time it seemed a good idea and so a new Gloworm condensing boiler was installed and despite it being far far cheaper to run than our old system and far quicker at warming the house and hot water, I am now really regretting it.

Our house is regularly let for short lets - normally 6 to 9 months over the winter and over the past few years we have had several issues of pipes freezing in the loft in and around the boiler. Our tennants seem to close the system down when they go out not thinking the temps will drop rapidly in the loft!!. So far it has cost us a new pump, and a few bits and pieces in the boiler and a few new pipes around the boiler. This last winter, despite having good tennants and the heating running almost continuously, the condensation pipe froze up causing the boiler to shut down - so another emergency callout visit from the plumber and now I live in dread of what will happen this winter.

One thing has occured to me, the loft mounted boiler has a flue going vertically through the house roof. Quite neat actually and to me not a problem but is there any way of extending that downwards and placing the boiler inside one of the bedrooms? Directly under the boiler is our airing cupboard which also houses the HW cylinder. and has access to all the service pipes gas and water. I would not mind losing the airing cupboard space if the boiler could be fitted there?

A secondary issue, if it is possible to lower the boiler position, would we be better off using a combie boiler and lose the HW tank from the airing cupboard and the CW tank from the loft. Then no pipes would be in the loft at all and so we could insulate if far better as there would no fear of damage up there due to the cold.

Your advice and opinions most eagerly awaited.

 

[SimonH2]

Condensate drains freeze on all sorts of installations - mostly because quite a few are done by plumbers that aren't prepared to take the effort to keep the drain internal (or at least try and persuade the owner that it's a good idea). How common is it to see a boiler within a few feet of the kitchen sink, but the drain goes outside ? Mind you, don't get me started on the stupidity of false backs in kitchen units that make the services inaccessible for maintenance

The main answers to your issues are :
1) Lagging. All the pipework needs to be properly lagged. Unlagged pipework will freeze quite quickly in a cold space.
2) Pipe & frost stats. If the system has components that are in an unheated space, then there must be a frost stat. Typically you have an air stat that turns the system on (in heating mode) when he air temp is belowsome low temperature, and then there is a pipe stat on the boiler return that will turn the system off again when the return is warm (30˚C ?). This keeps the pipework warm even if the system is turned off at the programmer - tenants should be instructed not to turn off the system power (if they do, then bill them for any costs/damage).
If these stats weren't fitted then the plumber was incompetent.
3) Consider building a "wardrobe" round the boiler - just light studwork and some hardboard or ply should do. Lag the space between the boards, and leave out any loft insulation at the bottom of the space. For the same reason, it's advised not to insulate the loft underneath the hot water header tank (and CH F&E tank if present).

4) Create a "user manual" for your installation. This should detail the controls fitted to your installation and how to use them. Detail what the tenant should and shouldn't do (eg "Do NOT turn off the heating supply").

EDIT: 5) Consider replacing the switched fused spur for an unswitched one so that it's not easy to turn off the mains supply.


As to getting a combi, my feelings on them are fairly well known and include no positive comments. They are unsuitable for other than a single bathroom, they have to be high power to supply a modest flow of water, but then can't range down to be efficient at heating an average house (because for the heating load they are grossly oversized). Keep your current setup - it's far superior in nearly all respects.

 

[SimonH2]

Oh yes, and as far as is possible, all pipes (well the horizontal runs) should be under the loft insulation. Ie, the insulation shouldn't go under the pipes, it should lay over the top of them.