Central heating problem

[glasgowcyclist]

Why is my condensate pipe constantly dripping water?

We awoke yesterday to find that it had frozen solid overnight and shut down the CH. I thawed it with a kitchen blowtorch, wrapped some pipe insulation around it and the heating worked fine after that but has frozen overnight again.

I don't want to be out there nightly for the rest of the winter so if anyone could suggest a cure I'd be very grateful.

 

[byegad]

My son had a similar issue. The problem turned out to be the length of the pipe was such that the steam emitted from the burned gas had time to condense then freeze before reaching open air. Cutting 5 feet off the pipe permanently solved the issue.

 

[glasgowcyclist]

My son had a similar issue. The problem turned out to be the length of the pipe was such that the steam emitted from the burned gas had time to condense then freeze before reaching open air. Cutting 5 feet off the pipe permanently solved the issue.

My pipe exits the outside wall then bends twice at 90 degrees so that it is pointing back at the wall (effectively a c shape) and total length is about 4 inches. I don't think I could have it any shorter...

 

[Levo-Lon]

Very common call out is a frozen condensing boiler outlet..

You saved yourself a few bob.

 

[lazybloke]

Why is my condensate pipe constantly dripping water?

You should be celebrating the efficiency of the condensing boiler, not questioning its fundamental design feature!

When I last looked into boiler placement, I seem to recall that condensate pipework could be routed to an internal drain*; is that an option for you?
Otherwise you need better insulation.


* Caveat: I'm not a professional.

 

[sight-pin]

My pipe exits the outside wall then bends twice at 90 degrees so that it is pointing back at the wall (effectively a c shape) and total length is about 4 inches. I don't think I could have it any shorter...

That doesn't sound like the condensing pipe but rather the pressure relief valve pipe if it's copper, condensing pipes are normally plastic and enter a drain etc. I think

 

[glasgowcyclist]

That doesn't sound like the condensing pipe but rather the pressure relief valve pipe if it's copper, condensing pipes are normally plastic and enter a drain etc.

Yes, it's copper so you could be right, thanks.
I don't see a plastic pipe anywhere.

The question still remains: why is it dripping? The pressure of the boiler at rest was just above 1, and 2.5 while running.

 

[slowmotion]

To reduce the chance of the condensate pipe freezing up, it's quite common to use a larger diameter plastic pipe. The section coming out of the boiler is about 22mm OD. Keep that length as short as possible and run it into a 32mm pipe. Make sure that there is always a fall on the pipe runs so that water can't collect in horizontal sections.

 

[sight-pin]

Yes, it's copper so you could be right, thanks.
I don't see a plastic pipe anywhere.

The question still remains: why is it dripping? The pressure of the boiler at rest was just above 1, and 2.5 while running.

May be it's not a condensing boiler if it's an older version and if you can't see a plastic pipe out the bottom of the boiler?
As far as i'm aware the valve can get a little bit of scale under the seal and cause it to weep, but that having said, i wouldn't of thought by unfreezing the pipe would get the boiler going again if it's from the pressure relief valve. If it doesn't seal itself best call a plumber.

 

[User6179]

Yes, it's copper so you could be right, thanks.
I don't see a plastic pipe anywhere.

The question still remains: why is it dripping? The pressure of the boiler at rest was just above 1, and 2.5 while running.

1 to 2.5 seems a tad high, my old combi boiler would only rise half a a bar on use and on my new boiler it hardly rises, your expansion vessel might be knackered.
Turning the boiler down might help as the hotter the water the higher the pressure.

 

[glasgowcyclist]

1 to 2.5 seems a tad high, my old combi boiler would only rise half a a bar on use and on my new boiler it hardly rises, your expansion vessel might be knackered.
Turning the boiler down might help as the hotter the water the higher the pressure.

New expansion vessel and pump were fitted about four years ago.

 

[byegad]

My pipe exits the outside wall then bends twice at 90 degrees so that it is pointing back at the wall (effectively a c shape) and total length is about 4 inches. I don't think I could have it any shorter...

If it's that short and in that configuration I think it's a more modern bailer than the one I mentioned. IIRC when we got one like this the plumber said that nothing should be routinely coming out of that pipe, it's their for 'if there's a problem'. Of course he's a plumber and his lips were moving.......

 

[User6179]

To reduce the chance of the condensate pipe freezing up, it's quite common to use a larger diameter plastic pipe. The section coming out of the boiler is about 22mm OD. Keep that length as short as possible and run it into a 32mm pipe. Make sure that there is always a fall on the pipe runs so that water can't collect in horizontal sections.

I think they changed how condensate boilers work, the old ones trickled water out which caused freezing , on newer ones they collect the water up and then dump it out, still better to have an internal pipe though.

 

[Tim Hall]

It's meant to drip. It's the way condensate from the boiler escapes. Condensate is produced during the normal operation of a condensing boiler. Here's Wikipedia link:https://en.m.wikipedia.org/wiki/Condensing_boiler

 

[User6179]

New expansion vessel and pump were fitted about four years ago.

PRV leaking then but you would think if you are losing water you would be losing pressure.