Condesate Waste Pipe Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Mike G Philip]

Like many I have had a problem with a freezing consensate pipe from my boiler. It is external and lagged but, with the recent extreme weather.....!
I want to replumb the pipe internally and do not know why the installer didn't do this in the first place. I have checked all the requirements and can direct the pipe vertically down through the kitchen worktop and then at an angle into the upstream side of my kitchen waste pipe trap (where the washing machine/dishwasher also are plumbed). The air break would be provided by the sink itself.
I would like to get a very good bathroom installer I used this year reroute the pipe.
Does this work, however, have to be done by a gas safe engineer or can a qualified plumber do it

[plumbbob]

I don't believe there are any restrictions on who can do the work.

[alldown2me]

Had a similar problem where the condensate pipe froze. This led to the water backing up in the boiler before it fried the mother board on the system. It took hundreds of pounds to replace.

I bought a washing machine waste pipe and connector and fitted it directly to the condensate outlet. It now drains internally into a bucket which I empty on a regular basis.

[htg engineer]

Fitting a tundish would be a better solution, as if it did back up it wouldn't get as far as the boiler.

External condensate pipework should take the shortest route possible and the pipe diameter should be no less than 32mm.

If you install to a gutter make sure it's not sitting in the gutter the same with a gully as when snow builds up it prevents the flow of condensate. Condensate pipework discharging into a gully ? the pipe should go beyond the grate.

Lagging the pipework wont really help if the pipes have the correct fall, as flowing water shouldn't freeze, it's when there's no fall and water is lying in the pipe or the outlet of the pipe becomes blocked and the water backs up - that's when it freezes.

Freezing condensate ? - most are down to poor installation/workmanship. Have heard of a few where soil stacks (110mm pipes) have frozen, and installed as per regulation/manufacturers instructions, all blamed on the cold weather, bizarre that water will freeze in a 110mm pipe ?? - but the pipe had to be blocked to start with for the water to freeze.

htg

[jimhet]

As htg engineer states, most of the recent problems were due to poor installations. Apparently there was close to 50,000 frozen condensate pipes in the space of 2-3 weeks so maybe its time for all new boiler installations to be checked/tested by someone other than the person that
installs it. However regardless of the amount of naff installers around, a
so called state of the art [or should that be arc] central heating boiler that
ceases to function because of cold weather is surely not fit for purpose. but no doubt Joe Mug Customer will be asked/told to pay for both cock ups.

[Mianpeacock]

I have had the same problem for the last two winters. I've found and fitted a device that automatically comes on when the weather hits below 2.5c and heats the condensate pipe. Touch wood it's worked so far.

I got it direct from a company in Cornwall. Google "tedcon.com"

[MainRaven]

Our boiler is at eye level in the kitchen, and the condensate pipe taken outside and into the soil pipe which comes down from the bathroom above into a drain underground. Hence the condensate pipe is very short and enters the soil pipe at about 5 feet above ground level. Maybe the 110 mm soil pipe won't freeze, but the drains somehow got blocked, someone emptied the bath, the water backed up the soil pipe, and the only exit was back up the condensate pipe, flooding a whole bath full of water through the boiler and into the kitchen. New boiler required! This is a problem the boiler manufacturers know about, but will not accept liability for.

[Mike G Philip]

That is EXACTLY what happened to us when the boiler was first installed. The guy piped the condensate line into the rain downpipe which goes to a soakaway. One major downpour, the downpipe backed up and we had a kitchen full of water via the boiler. Hence they redirected the pipe outside. Anyway, had a guy in who is going to route it internally to a sink wastepipe - problem solved I hope. Having researched this quite a bit now, every piece of guidance I can find recommends internal routing wherever possible. I think the installers just see the outside route as a quick fix - especially if you're on lump sum...!!! Thanks all. Mike

[htg engineer]

Yeah that happened to one of our jobs too, luckily just needed new fan/pcb and gas valve.

They wont take liability because it's not their fault.

I wouldn't install a boiler with the condensate connected to the soil pipe below the toilet, you're asking for trouble if you do get a blockage. Have heard of one filling the boiler with faeces not just water.

Again installer to blame.... quick install but not taking other factors into account.

htg

[Mike G Philip]

htg - thanks. I do not intend routing to the toilet or a foul waste pipe but into the sink wastes. I have a double sink and the boiler is 1m above the highest sink level so likelihood of ever backing up virtually impossible. I have also checked the bloier maker installation instructions and the Government assessment guidelines for details re connection points/traps etc.