Leave boiler on, or not?

[RockySpears]

Moved house, but still have old one.

Insurance says water must be turned off.

Leaving boiler on to prevent pipes freezing, house thermostat set 10deg. C or so.

Boiler has pre-heat for water, no tank or anything, it just keeps the domestic water warm in the boiler.

If I drain the domestic water, will this knack the boiler as its pipework will be empty?

Additionally, which Regulation writer ever let boilers go in the loft?  Frost stat keeps boiler (in new house) running all day and night as it is cold right now and no amount of heating is going to change the temp in the loft.  So the hatch is open, great, very green and very expensive.

Yours,

Annoyed of Stockton,

[figgy]

Frost stat should do its job, most boilers have a stat for the boiler so it will save the boiler. The house pipework will be protected via the boilers stat and you setting the thermostat.

Trouble with draining is getting all the water out, any left lying in low points could freeze, you would have to blow the system through with air or add antifreeze inhibitors.

[JohnfromUK]

37 minutes ago, RockySpears said:

Frost stat keeps boiler (in new house) running all day and night

My boiler inbuilt frost protection cuts in at 5ºC (Worcester Greenstar 42CDi) according to the manual, so unless your loft is VERY cold, it may be another external frost stat driving it on - which may be set much higher?

My boiler is in an external boiler room (more like a cupboard really) and I don't think has ever come on as there is enough background warmth from its last running.  May be worth removing a small area of insulation (fold back to try?) just under the boiler

[figgy]

Chances are in the new house your minimum setting is quite high on your thermostat. You have a temp for when you call for heating, mornings and evenings for instance. The fallback temp is the temp setting you don't want the house falling bellow.  Check the manual for your thermostat. 

[crossy 666]

You can add antifreeze to the the heating system but would need to drain the fresh water side 

[RockySpears]

1 hour ago, figgy said:

Frost stat should do its job, most boilers have a stat for the boiler so it will save the boiler. The house pipework will be protected via the boilers stat and you setting the thermostat.

Trouble with draining is getting all the water out, any left lying in low points could freeze, you would have to blow the system through with air or add antifreeze inhibitors.

So is a frost stat just saving the boiler?  Is it not to prevent the house water pipes freezing?

 

1 hour ago, figgy said:

The fallback temp is the temp setting you don't want the house falling bellow.  Check the manual for your thermostat. 

There is a frost stat beside the boiler, in the loft, on an external wall.  No matter the amount of heating, the frost stat will be cold in cold weather so the heating is on.  I don't see that anything else can fix that.  Your lost is supposed to be cold so putting a boiler there is mad (to me anyway).  I'll just have to get it moved down.  Mind you, keeping it warm is good for my damp rafters.

 

1 hour ago, JohnfromUK said:

so unless your loft is VERY cold

-2 or 3 recently.

 

RS

[JohnfromUK]

5 minutes ago, RockySpears said:

-2 or 3 recently.

That is cold - and you do need protection.  I have no plumbing in my lofts now, but previously (to a big replumbing and wiring upgrade) I have had a whole lot - and it very rarely went near freezing.

[enfieldspares]

5 hours ago, RockySpears said:

Moved house, but still have old one.

Insurance says water must be turned off.

Leaving boiler on to prevent pipes freezing, house thermostatditionWhich Regulation writer ever let boilers go in the loft?

Simple...Isaac Newton...and his Laws of Gravity.

Fully drained and fully turned off no there should be no issues.

[Jim Neal]

You don't say what type of boiler it is.  Combi?  Condensing?  There's quite a few plumbers on here I think who could give you a more detailed answer but my belief is if it's a "closed" system you can leave the boiler functioning with the mains water shut off.

It's a bitter pill to swallow but you just have to accept that there's always going to be a background running cost even when a house sits empty.  I've got the same problem myself at the moment, being between tenants in a rental property I own.

If you've got a condensing boiler in a loft that goes below freezing you've got big problems because the condensate will freeze in the pipe, back up and cause a shut-down.

I'd maybe look at insulating the rafters.

Generally for the health of the building you shouldn't let it sit cold for ages, it'll get damp.

 

[udderlyoffroad]

18 hours ago, RockySpears said:

Moved house, but still have old one.

Answer is, get a tenant in there quicksmart.

 

18 hours ago, RockySpears said:

So the hatch is open, great, very green and very expensive.

Why you doing this though?

The boiler only needs enough heat to keep it above its preset frost temp.  Close hatch, get on with life, and consider your options for insulating the loft space at your leisure.

If you're not convinced, have a 24h period of the hatch open, and another one with the hatch closed.  Take gas meter readings and work out what it costs you.  I suspect it's actually costing you more to leave it open.  Obviously try to pick 2 x 24h periods where the outside temperature is roughly the same

 

16 hours ago, RockySpears said:

Your loft is supposed to be cold so putting a boiler there is mad (to me anyway). 

Why is it supposed to be cold?  Depends on where the insulation is.  More enlightened countries use the roofspace as living area and insulate between the rafters.

Remember, a boiler is heating *water* not the air around it, so it depends on the temperature of the water going in, rather than the ambient temperature.

But yes, putting a boiler in the loft is mad from an maintenance point of view.

 

[RockySpears]

37 minutes ago, udderlyoffroad said:

Why you doing this though?

To keep the loft space above the frost stats temp.  Otherwise it runs and runs in cold temps and its running cannot raise its surrounding air temp because there is no radiator in the loft.  Leaving the hatch open means it gets warm air around it to "appease" the frost stat.

 

40 minutes ago, udderlyoffroad said:

Why is it supposed to be cold?

If the house is well insulated, the loft space will be more or less the same as the outside air temp.  You have vents in the eaves specifically to allow outside air into your loft to prevent moisture build up.  Just the same as air bricks for under wooden floors.

 

I have left things this way:  The old property has the water off, but not drained, so the house does not freeze and the pre-heat system fells happy.

The new house id getting the boiler moved, there is no shortage of downstairs space and it was a silly idea to put it up there in the first place.

Thanks all,

RS

[udderlyoffroad]

24 minutes ago, RockySpears said:

Leaving the hatch open means it gets warm air around it to "appease" the frost stat.

As I said, I think you need to actually compare the gas consumption with and without the loft hatch in place.

The frost stat should be just that, to prevent frost damage, so can be set fairly low.  A properly designed system will not necessitate constant running.

 

27 minutes ago, RockySpears said:

f the house is well insulated, the loft space will be more or less the same as the outside air temp.  You have vents in the eaves specifically to allow outside air into your loft to prevent moisture build up.  Just the same as air bricks for under wooden floors.

Only with the old school, insulated ceilings and free circulating air model of poorly insulated British houses!

I'm not disputing for a minute some a-hole who didn't know what he was doing installed your system (or more likely, tried to tell his client what they were asking for was a bad idea), but you shouldn't have to move the boiler.

I strongly urge you to get actual data first, rather than your gut instinct of 'oh it's constantly running' before making any decisions.

[12gauge82]

Why not just insulate around the boiler, lag any exposed pipes to it and remove the insulation between the ceiling and boiler,would only cost a few quid and problem solved.