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[dave1969]

can any one tell me if rainwater getting into my combi down the flue is common if it is what is the remedy

[bobplum]

im no heating engineer just a plumber but when in peoples houses they do point this out to me on various occasions
you would need to consult a heating engineer to see if the particler vent can be covered etc

[marrtin]

The flue is so designed that any condensation (or rainwater) will run back into the boiler and consequently into the condensate trap mechanism. This is perfectly normal and harmless.

[dave1969]

thanks for the reply. can you tell me if there is so much water going into my combi that it causes the boiler to fill with water would that maybe be the trap blocked,or a leak inside the boiler.your advice is much appreciated.

[htg engineer]

That's ok Marrtin - if it is a condensing boiler. He hasn't said what type of boiler it is.

You shouldn't really get rainwater entering the boiler flue, the odd occasion - ok with heavy rain and winds, if it's a common problem then you need to look at the positioning of the flue, the flue terminal and see if it should be replaced or the flue re-routed.

What type of boiler ? is it a vertical or horizontal flue ?

If it's a horizontal flue it couild be that the flue is too short, so any water running down the external wall would enter the flue.

[marrtin]

Indeed you are right Htg Engineer, sorry I missed that point.

[htg engineer]

"thanks for the reply. can you tell me if there is so much water going into my combi that it causes the boiler to fill with water would that maybe be the trap blocked,or a leak inside the boiler.your advice is much appreciated."

What's the make and model of boiler ?

If the boiler is actually filling with water then it's probably a water leak, not just rain water, if the trap was blocked the boiler should go to lockout,