Cold water tap seems frozen. Is it safe to run the central heating boiler?

[Sandy-Wroe]

If it's not we're going to have to make last minute Christmas arrangements.

[buildersmate]

If you mean the main supply pipe into the house is frozen, such that you have no cold water at the kitchen tap (amongst other places), there is no reason not to run the CH.

[Sandy-Wroe]

OK Thank you, Blildersmate. That's a relief. At least we'll be warm. I'll go later and buy a lot of bottled water

[Wak]

Just out of interest, one house I used to live in regularly had the incoming mains water pipe frozen every year. I later found out that the incoming water pipe was immediately beneath ( and touching) the paving flag in the front garden, consequently the water froze as soon as it snowed. During the following Summer I lowered the water pipe, covered it with insulating material and then replaced the paving flag. No more problems after that.
You would have thought that the builders would have known about these things, wouldn't you??

[weeal]

My old mum has the same problem this morning, a plumber told me over the phone to only use the heating as long as its remaining warm in the rads, if it starts to go cold you must switch off the boiler.

What a worry for you on xmas eve

[buildersmate]

It is actually not installed to water authority spec. unless the pipe is buried a minimum distance underground (about 450mm from memory - out of reach of most cold weather snaps).
Builders do, of course, know these things but then again it cost more time to dig a deeper trench.