Combi Boiler Winter Air Intake

Gerry_P

In my own home I've got a Laars Mascot combi boiler, also sold as a Bradford-White Brute, 140K BTU. Living in Northern Ontario, combustion air coming in is very cold in winter. I noticed water dripping from boiler and on investigating, the intake air fan was soaked with condensation which drips down over the heat exchanger and eventually to the bottom of the steel cover and is actually causing it to rust.

If I leave the front cover off it minimizes it a lot but then it's pretty noisy as it's quite a loud fan to begin with.

Has anybody else had complaints from customers about this or come up with a solution? For now, I just redirected the intake from outside to take inside air but that's not an ideal long term solution.

Any ideas are much appreciated.

GroundUp

How long is the intake pipe inside the building and how is it terminated outside? Outdoor air is very dry in winter and typically would not cause anything like this unless it's recirculating some flue gas or drawing in precipitation. There should also be a drain in the intake elbow inside the boiler for instances like this, but if this is an early model it may not have one yet.

Kaos

I'm in a bit warmer location in southern On, but I never had condensation issues with fresh air intake. Many moons ago had a condensing tankless water heater that had that drip on the intake and it never produced a single drop of water.

I'm with @GroundUp , most likely you are recirculating exhaust.