Condensate tank under boiler is overflowing - any plumbers out there?

[fresh]

Worcester Bosch Greenstar boiler, and we have a pump to take away the condensate. The pipe from the reservoir runs up into the loft and then joins into a bathroom waste pipe internally (i.e. it doesn't go outside at any point). Having been up into the loft it's cold, but not freezing although it may have been freezing earlier in the week.

The tank is full, and the condensed fluid is seeping through the top. We've put another tray beneath it so it's not coming through the ceiling anymore. The boiler is still working. The pump is still coming on although can't tell if it's actually pumping anything.

Any plumbers out there who can give any advice before I can get someone here on Monday? Anything else I can do? I'm assuming the boiler will just stop if it needs to rather than do anything more dramatic.

Any help gratefully received!

"The pipe from the reservoir runs up into the loft and then joins into a bathroom waste pipe internally"

don't like the sound of that

water doesn't run uphill so you mean it has a pump to take it into the loft?

Well-insulated lofts are unheated space and very cold, so any plumbing needs a lot of protection.

any pipework in the loft is likely to have frozen. If you think you can see where, try a hairdryer on it (but use nothing hotter)

I hope all pipes in the loft are lagged with Climaflex or similar in the BS grade which is as thick as your arm? If so, look for gaps where it has come apart or gaped at bends. If not, obviously fit it once you have solved the problem.

Curious pipe runs are frequently because householders don't want their new flooring taken up, or their kitchen units disturbed, or their new decoration to be marked. The ill-effects of frozen condensate pipes are so huge that I hope they will reconsider.

If by any chance your boiler is, or near, a kitchen, please try to have the pipe run changed so it goes into a drain there.

Yes, as I said it's pumped out and the pump is still coming on. It's run through the loft to avoid it being run outside, so that it wouldn't freeze! And the kitchen is further away than the bathroom. The loft is cold, but not freezing at the moment and actually it's not that well insulated (I know, don't tell me, it has some but could probably do with more. Another thread I think).

We can't get to the section in the loft, there isn't the head height to get in there with a hairdryer.

I'd really just like to know whether I can just wait for it to thaw (getting warmer here and will be 5deg tomorrow) without anything ghastly happening. The boiler is still working.

put a big bucket under it, empty it frequently.

Condensate is slightly acidic (like tomato juice) and will attack concrete, mortar, marble, limestone etc.

It sounds to me like it is being pumped away from the boiler, so the boiler will not get flooded and cut out (they have this protection which usually turns off the boiler when there is a frozen condensate pipe)

it would be a tremendous coincidence if there was a cause other than freezing, in this very cold week.

condensate can also be drained to a rainwater gully, if you have a combined rain+foul drain, but not to a soak-away as it will dissolve the rubble. It must not be allowed to leak into the ground next to your house as it will attack the foundations. If it is drained to the ground, it has to pass through a neutralising vessel of limestone chippings, which it will slowly dissolve.

Thanks pigletjohn

p.s. if more convenient, you can undo a screwed-joint in the condensate pipe near the boiler, or even cut a pipe, so that it drains into a bucket which you must keep emptying. This trick can also be used by people whose condensate pipe runs outside and gets frozen. Obviously you will have to mend the pipe as soon as things improve.