Boiler in loft, advice please

[Nikced]

We had the boiler replaced in November just after we moved in. Also had it relocated to the loft to make space in the kitchen.

Its an Alpha boiler, recommended by experienced plumber, with a wireless/walk round with thermostat, knows what temp it is in each room, appears to be working fine during the day. He also put in radiator thermostats all over.

Since the really cold weather has started the boiler goes on and off all night. The radiators are set to to 3 (of 5) and the thermostat set is on 5 oC.

In the middle of the night the radiators get really hot and the boiler appears to be ignoring the thermostat. Plumber put extra lagging around the boiler in case it was getting too cold but not made a difference.

It is impossible to sleep as its so hot! Does anyone have any advise to help?!

[PigletJohn]

It is probably the frost protection thermostat which will keep the boiler and pipework warm if it gets too cold. I an not in favour of putting boilers in cold places. I would have expected your installer to know that.

Alphas have a good reputation.

It sounds like you have TRVs on your rads. They should not be set so high that the rooms become uncomfortably warm. Turn them down a bit.

I suppose you might think about building an insulated cabinet or shed around your boiler and pipes to keep the cold wind out. Have you got an unfelted loft? Where are you and how old is the house?

[PigletJohn]

p.s.

It might also be the weather compensation circuit, if fitted. These are supposed to let the boiler turn itself on at different times if it knows the weather is unusually cold and it considers extra heat to be necessary. They are said to improve economy and comfort. Some people, including me, find it difficult to understand what they're up to, and don't like a sentient boiler making its own decisions. Some people have weather compensation removed if they can't get on with it.

[LondonSuperTrooper]

Watching this thread with an interest. We are buying a small house and we've recommended to install our new boiler in the loft.

[Nikced]

Thank you so much PigletJohn, our plumber said Alphas were a really good make and this was the best of their boilers and that it was suitable for the loft.

The radiators are set in the middle of the options, we have tried lower but then it tends to be a bit cold when on during the evening, have started turning bedroom rads off just before we go up, is still a little chilly in the mornings though!

House was built in the 50's, we are in the South East and the loft has absolutely loads of lagging that previous owner put in, also has felting.

Plumber has said he will build a box and insulate (he is now a bit worried as he has put same boiler in other lofts since ours) this will take some time though and we wont know if it has resolved the problem until next Winter as the weather is warming up.

The other option he has given us is to replace with another boiler, is there one that is better for lofts or do they just not belong there?!

Spent an absolute fortune on copper piping etc to get in up there as it had to travel the length of (very long) house. Feels like the whole thing was a waste of time and money

[yomellamoHelly]

Ours is in the loft, but its a Vaillant. Don't know how that compares. Has an eco mode where it will click on automatically (ours is set at 14 degrees) if the (portable) thermostat drops below this. Otherwise it goes as per its timeslots. Tend to leave thermostat in warmest room of house overnight. In day goes in coldest area of house. Haven't had any issues with it (other than figuring out the controls) in the three years its been in.

[Nikced]

Thank you Helly, plummer is calling Alpha tomorrow then me back in the evening to arrange when to come and look.
I'll ask what temp it the boiler is set on, usually turn portable thermostat down to 5 degrees when out, as the timer is set to turn on when needed. It then doesn't matter what room it is in I think?
I'll look at Vaillant boilers, do they make a noise when they turn on do you know? One bedroom is right below our boiler and if you are awake because it is hot then you can hear it going on and off!

[PigletJohn]

From what I hear, Alpha is rated a bit better than Vaillant or Worcester-Bosch, which are the most popular, dependable, mid-level brands.

I would expect it to modulate the flame size and fan speed down according to demand, my own boiler always tries to start very low (and quiet) and then revs up if necessary.

If your loft boiler is hung on a brick gable or party wall, so spaced away from the ceiling, you may be able to muffle the sound a bit by building the insulating cabinet round it.

I'm not keen on wireless thermostats, as they give an extra level of potential failure. With the boiler in the loft you will not always know if it is communicating correctly.

As the weather becomes milder, I turn down my boiler stat so that it runs (quietly) at smaller flame size, but for longer periods than if it was running hot. This saves it switching on and off so often. The boiler stat must always be set higher than the cylinder stat, otherwise it will never stop trying (unsuccessfuly) to satisfy the demands of the cylinder. Modern condensing boilers run at their most efficient at about 60C.

As for TRVs on radiators, they work like the thermostat on an oven. If the room is below the preset temperature, they're on; if it's above, they're off. They have a very small range where they will be partly open, and they will seldom be in it. So if correctly set, the room should be neither too cold nor too hot. Feel the pipes when the heating is running, if they are both too hot to hold for long, then the valve is open (or was, in the last few minutes). If not, it is closed. You may need to alter the setting a fraction over a few days to find the ideal setting, then mark it with a dot of felt tip. It may be different in different rooms.

[mrswimpeydimple]

I have had a Valiant beer installed in my loft at the end of January, plus all new pipes, roads and TRVs. All tickets boo . I may be missing the point here but do you have your CH timer on 24/7? C My CH is set to go off before I go to bed and then it doesn't go on again until 45 mins before i get iphone in the morning so no chance of getting hot in the middle of the night. Boiler is also silent, .ever hear Iraq even when its on.

[mrswimpeydimple]

Sorry for typos, ruddy phone auto correcting. Boiler not beer!!