Lenth of condensation pipe from a boiler Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[collectors]

Hi, we are fitting a boiler & are about to fit a 22mm condensation pipe from the boiler to a waste pipe in the bathroom, but the length of run is around 11 meters with a nice slope. What is the maximum length this can be in 22mm?.
The only info with the boiler is that on a long run, increase the pipe to 32mm.
But! what is classed as a long run?

Thanks

[htg engineer]

You must be Gas Safe Registered to install a gas appliance. Employ a gas safe registered engineer to install the boiler.

[collectors]

The boiler is being fitted by a gas safe engineer. We was helping by getting some of the pipework to the boiler area. The engineer said he will call the manufacturer & this is the answer they gave & found the reply very odd.

[htg engineer]

11m is a very long run, I wouldn't install 11m of internal condensate pipework, you need 45mm per metre fall. By the 11th meter you'd need to be 19.5" lower than the 1st metre, which you will not get under a floor.

You need to look for the shortest route, 3m or so. Fit a tundish to help with flow, make sure you have minimum of 45mm fall otherwise they can back up and cause costly repairs to boiler components. If you cannot reduce to a 3m length, then you need to look as pumping the condensate.

htg

[collectors]

Hi, thanks for getting back. The boiler is a wall mounted glow-worm sited on the gable end wall in the loft of a bungalow. For the small difference in price we have put in 32mm waste from the outlet in the bathroom which is 9m away & just made the last 500mm to the boiler in 22mm pipe. The main reason for not going the shorter route of around 5m's is the amount of times we have had customers & friends having the condensation pipe freeze in the winter, even though some were lagged.
We had -14 here a few times last year.
But will pop in tundish to help.

Thanks

Chris