Do all modern boilers have a frost protection thermostat?

Simple answer - No Some wall mounted oil boilers (Boulter are one) have in-built frost protection but you didn't tell us what make and model yours is

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember MM saying something like:

Not as standard, not generally. It's covered by a 'should' in the installation manual and that's good enough if the fitter is competent. A lot of boilers will be installed where an inbuilt frost-stat would be no use, and that's just a waste of money as far as the makers are concerned.

To do that I'd have to put on Arctic weather gear and go into the garage. It's ruddy freezing in there! I do know it's wall-mounted, though.

MM

Haven't you got the manual filed with all other instruction manuals and warranties?

As others have already said, the answer is: maybe. :-)

However even if the boiler itself has frost protection that won't protect the pipework connecting the igloo in which the boiler is installed to the rest of the building, so a separate frost stat is often required. And a pipe stat on the return to turn the boiler off again when the pipework is up to a safe temperature. And if the system is an S-plan, either the bypass should be within the frost-free area of the house or the frost-stat should be interlinked with the zones.

I've got a spec sheet somewhere. Dunno about a manual. I just push an override button on the timeswitch and the heating comes on. But lately, in the very cold weather, I have a suspicion that I have heard the boiler coming on of its own volition, suggesting that it's mighty chilly in that thar garage. Later today I shall venture out and move the garden thermometer to the garage, then see what the inside temp is tomorrow at 6:00 am. I've been manually switching on the boiler for 30 mins last thing at night and first thing in the morning when the weather was at its coldest. The coldest room in the house that is heated only minimally because it's never used never had the temperature drop below 8 deg C, as the house is very well insulated.

The boiler is mounted on the inside of the external wall in the garage. That is, the garage abuts the house, so there is only one external wall. The pipework from the boiler is all inside the garage, where it disappears through the garage ceiling into the garage roof space before being routed across to the house. So the danger point (for frost) would be mainly the garage roof space, I reckon.

MM

Check with the makers