I have a house that will sit unoccupied over winter and I wish to check it is protected without going as far as turning the heating on 24 7

My boiler has a frost protection mode that kicks in when it sees less than 5 degrees at the boiler. My radiators also have thermostats which have a low frost setting of 8 degrees. I guess part of my question is will this set up protect the remote parts of the house away from the boiler? If all the thermostats are set at 8 then they should get flow when ever the boiler kicks in as long as they have not frozen first. The boiler is against a single leaf external wall in a porch so it should be one of the colder places of the house.

The next part of the question is hot and cold taps, showers and toilets. If the frost protection is set at 5 degrees and the thermostats at 8 degrees then the house should not go much lower than 5 to 8 degrees? I was thinking of closing the open system and draining everything and chucking anti freeze in the toilet u bends but not sure if it is required if the heating system frost protection works as I think it should?

Ideas welcome. The house is a big enough disaster so don’t need more issues!

Further thoughts, maybe only the heating water temp will not go much below 5 degrees but that does not mean it is enough to heat the room air temp so probably still worth draining the open system?

Are you sure it’s 5 at the boiler or at the room thermostat. If former, that says it’s only monitoring return flow, though in principle that is not bad as long as the pump runs (which it prob won’t). If the later, then best thing to do is keep all doors open. Some boilers have external thermometers that will regulate the output and protection settings, same boilers often have the inputs to monitor pipe temps, could be worth putting one into the board and on a pipe that runs along an outside wall…? Mine is like this.

I think the boiler protection stat only cuts in to protect the boiler, so will only fire long enough to warm up the heat exchanger and pipework fairly close to the boiler.

I’d leave the boiler on a timed program with all rads on frost setting, and room stat turned down as well if you have one.

a different problem you may encounter, depending on your house, is damp. Open all wardrobes and cupboards and leave room doors open. If you have a house prone to damp or condensation maybe invest in a dehumidifier – dessicant types are best for lower temperatures which is what you’ll have if heating is only on frost setting. And you’ll need one that can you can run a hose from so you don’t need to empty the water container. Stick it on a kitchen workshop or table and run hose into sink.

The house is already burst with damp, hence unoccupied. Everything that can be open is open.

The boiler does not have an external thermometer, I think it is only water temp it is measuring. If it drops below 5 degrees then it will fire the pump, the second it does this it gets further cold water from the rest of the system. As the radiators are open until 8 degrees then the system should try to stay above 5. Just not sure if this will have a real heating effect on the room volumes as a whole and helt to protect the other water pipes which serve outlets

Just put the heating on once a day from (say 6pm-10pm) with thermostat set at (say) 12. In my opinion the lower figures you are quoting will mean parts of the house, e.g. roof space where pipes are, will be close to or below zero. I would not recommend draining the system and having no heating at all as the house will get very damp and you’ll have more problems.

Have someone visit the house once a month, aside from being a good idea it’s also a condition of the house insurance I suspect.

I visit the house at least once a week, just getting a feel for it as it goes into winter.

I am not proposing to drain the heating system as it can cause other problems, only the open outlet side of stuff which is not heated as it is either cold water outlets or hot water with no demand.

If it is only running on a set timed logic then it could cool right off on a prolonged cold spell when I might not be able to get near the house.

Two choices really, risk it or leave the heating on. I’d have the heating on tick-over all the time.

I have been thinking over those choices.

Found a good description of the frost protection on my boiler. When the boiler sees below 8 degrees it cycles the system water with the pump and monitor temp. This would draw any colder water from remote parts in the house as the thermostats are open. If the boiler sees below 5 degrees then it fires until 30 degrees system water temp. The radiator thermostats close at 8 degrees so should not take too long to heat system pipe work. Seems pretty good logic to me.

I will probably chicken out and leave it on if I know we are having serious prolonged cold spells.

Might still drain the other water outlets for peace of mind.

Is the house insured? When mine was empty over the past two winters they said I had to either maintain the temperature at a minimum of 21 degrees or drain everything down! I don’t have it at 21 degrees even when I’m home!
I compromised by setting the boiler at about 1 out of 5 and having it come on for an hour in the morning and then for a few hours at night.
All was going fine till the diverter valve started leaking, the pressure dropped and the boiler shut down. Luckily it wasn’t that cold when it happened.

Is the house insured? When mine was empty over the past two winters they said I had to either maintain the temperature at a minimum of 21 degrees or drain everything down! I don’t have it at 21 degrees even when I’m home!

Ours were a bit more reasonable and were happy with heating working on frost protection and checked weekly. We just set the heating to low and put it on a timer to kick in a couple of times a night. The neighbours popped in to check on it.

We have specialist insurance for the house in its current state. Thankfully it does not state a temperature level; 21 is very high! The place would be a big mouldy cooker at that temp! 😮

My timer unit and the boiler frost protection don’t appear to work in conjunction but might email the manufacturer to check as it seems a little silly.