Codensate and Carbon Monoxide

[John]

Due to the end of my condensate pipe being frozen in this first winter since installation (in the summer I will re-route it), I tee's off a by-pass to take the water to a bucket in a convenient cupboard.

A friend mentioned this to his Gas Service bloke who was horrified and said that Carbon Monoxide could travel down the pipe if the flue was to freeze.

The Boiler is a W/B 30cdi which has a siphon / trap on the condensate outlet.

Is there a risk? I would think that if the flue was obstructed then the control system would detect it anyway.

Any advice?

[Lobster]

I can't comment on the particular model of boiler, but it's very commonplace to have condensate running into a standpipe or whatever inside the house, ie open to the atmosphere - I've seen this arrangement in manufacturer's installation instructions.

[robert]

On my Valliant there is a trap on the condensate outlet within the boiler.

[cynic]

VERY unlikely. Most half decent boilers have a siphon trap and the casing runs under negative pressure if the manufacturer used sense in designing the unit. I think the cdi fan extracts from the combustion chamber but would have to check as I have not serviced one of that model.

[dennis]

I have never seen one like that, however i have seen one that empties into a condensate pump unit and I don't think they are room sealed. I have seen one that went into a 40 mm sink drain pipe but it had a one way valve fitted, probably because the pipe was connected to a Saniflo.

[Andy Champ]

Just FYI my elderly Glowworm runs the casing at positive pressure. The combustion chamber is entirely surrounded by this positive pressure except where the flue goes outside - so leaks are of fresh air.

Andy