New, free central heating, was re: boiler sizing

[invalid unparseable]

Hi, you may remember that I asked for some advice about central heating that we were offered and I am pleased to report that it has now been installed and commissioned. First impressions are very good.

The Combi boiler is very quiet.

The radiators work very well, especially the big one in the living room.

The wireless controller is also very good, although the timer programming is a bit of a challenge.

Six night storage heaters were removed and disposed of. They made a massive pile of bricks in the front garden before they were collected.

You may remember that only living, dining and bedrooms were to have radiators fitted and we managed to convince the surveyor that the two rooms at the top of the house (an office and a workshop/office) needed radiators. So we got seven in total.

One thing that I wsn't expecting: All the radiators have thermostatic valves except one, in the dining room. The explanation was that it would over stress the boiler if all radiators were turned right down. This surprised me a bit, but maybe it's correct?

I've never looked forward to cold weather before but now I'm keen to see how the system performs when the temperature drops.

Cheers

- Mike

[Andy Burns]

It's correct, normally the rad without a TRV would be the one in a bathroom, but I remember they wouldn't allow you a bathroom radiator (why?!). If at some point you can fit a bathroom radiator, I'd bank on fitting a TRV to the dining room at that time, and leave it off the bathroom one ...

[Andrew]

Can you now sell the house (at a higher price) and pocket the extra profit, or are there conditions attached ?

[Fredxx]

My policy is to have a radiator in a hallway without a TRV and have the house thermostat nearby.

Where is the wireless thermostat sited?

[John Rumm]

One would typically have the rad without a TRV in the room with the main thermostat. That way you get a system "interlock" that ensures the boiler is turned off when the whole place is up to the required temperature. (this is a building regulations requirement).

There is a secondary issue that if all rads have TRVs then when all closed you would block the flow of water from the boiler and cause it to trip out with an overheat fault. You can get round this with a automatic sprung bypass valve. Sometimes this is added externally, and some system and combi boilers include one internally.

[Jim GM4DHJ ...]

totly

[ARW]

Conditions were attached when I was wiring up boilers for such schemes.

[Andy Burns]

Am I misremembering that a bathroom rad would have traditionally been left as the "bypass", then?

[Vir Campestris]

The thing _not_ to do is to mount the thermostat on a wall that has radiator pipes immediately behind it.

Luckily it was a wireless one and easy to move!

Andy

[John Rumm]

Various things have been done with bathroom rads in the past, including placing them in the DHW heating circuit rather than the CH one, since that would add load to a slow recovery cylinder that would keep the boiler running longer without cycling on its internal stat, as well as keeping a rad hot for drying towels all year round even when the main CH was off.

A bathroom rad can be a bypass - but it ought to be in addition to the one in the room with the stat.

[Brian Gaff (Sofa]

I think in some houses, I do get annoyed with the plumbing noises in the thermostatic valves. Hopefully yours are not like that. In one building the residents call it hissing Sid!

I still have my storage heaters. I'm surprised if yours were still serviceable you could not have sold them. Brian

[Dave Plowman (News]

Makes more sense to have that as a towel rail. Which won't superheat the bathroom. And a TRV controlled rad if needed - as a towel rail may not be enough.

[Scott]

On Thu, 28 Oct 2021 12:09:38 +0100, Mike <> wrote: [snip]

I liked the story about the woman of 95 who qualified for free central heating from the Scottish Government. When the guys turned up, they said she would need to sign an undertaking to remain in the property for five years. She replied, 'Young man, I would be delighted to sign your form but at my age I don't see how I can responsibly give such an undertaking'.

[invalid unparseable]

That's correct the scheme only allows radiators only in living rooms, not halls, bathrooms, toilets or rooms just used for storage.

I can always add extra radiators later at my own cost. We'll see how it goes.

- Mike

[invalid unparseable]

The sheme doesn't allow bathroom radiators.

The wireless thermpstat/controller is currently in the living room.

- Mike

[invalid unparseable]

Yes, that's what I would have thought (no living room TRV) because one woul normally have the wireless thermostat controller in the living room.

Maybe I'll move the TRV from living room to dining room later.

The possible boiler overheat is what the installers said.

- Mike

[invalid unparseable]

Yes we can. There are no restrictions in selling the house on, but we don't intend to as we really like it, especially now it's warm when one wakes up.

- Mike

[John Rumm]

What make and model of combi is it?

(you may find it has an internal bypass anyway which fixes the overheat problem (even if it does not address the building regs requirement for a system interlock)

[Fredxx]

I presume there's nothing to stop you adding your own?

Which is not ideal, as occupancy is variable.

[invalid unparseable]

No noise from the valves as yet.

The storage heaters were in some cases, not working and some were so old they qualified for their pension. The ones working wern't sellable; They were some the same make (Duplex) on ebay locally recently but they didn't sell. Getting them to the tip is a massive job so having their disposal included in the service was excellent.

We did keep three storage heaters, just in case the new-fangled central heating packs up. (It does look awfully complicated).

- Mike