Thread: water in High Efficeincy furnace vent

I had a carrier High Efficeincy furnace insatalled in this past summer. First time I turned it on this year I hear a sloshing sound in the exaust pipe in the basement it sounds like a dishwasher. Outside I see white smoke and water coming from the exhaust. This doesnt seem right to me. I am afraid that water has collected in the pipe from rain. Can this cause a restriction which would cause CO build up in the house? Also could this damage the furncace coil? Can I install a drain or trap on this line?
Thanks

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• Furnace vent

Nick,
Your furnace should have been installed in such a manner that the exhaust vent slopes back to the unit, allowing all condensation to drain through the units inducer housing, to the factory trap, and out to the field supplied condensate drain line. Rain water would be handeled through the same means. There is an external trap kit available, designed to handle the furnace condensation without directing it back through the inducer housing, but this would still be connected to a field supplied drain
Very little water should be exiting at the outside termination.This should exist of water vapor only. There should be no "running" water exiting the vent This will lead to icing and freeze-up at the termination when the temperature drops to below freezing, eventually resulting in a no-heat situation.
With the furnace design, a build up of condensation in the vent will result in a pressure switch fault.
The vent should be examined by a trained HVAC technician, before creating an issue resulting in no heat when you need it most.

Yes, you have a problem with the system. Do not use it! Call a qualified HVAC contractor to make the repairs. Contact the original company and give them a chance to make it right.

Your furnace repairperson ought to be able to discover that there is a blockage in the drain for the combustion fan housing or in the condensate pan at the bottom of the exhaust condensor. I have seen this happen on my Bryant furnace when the temperature rise was too great across the heat exchanger. This results in solids building up in the bottom of the condensate pan and clogging the drain, thus resulting in the sloshing sound you hear. Cleaning the drain is a temporary fix. Have the temperature rise checked to see if it is within specs for the unit and have your repairperson suggest alternatives. We found that the simple solution was to be sure that the return air came from heated rooms in the building.

Thanks for the info guys. My hvac installer was here today and confirmed that the pipes coming from the furnace to the outside were not pitched properly during installation. He said that sometimes when system first starts up there might be a little moisture in the line but that it should clear within a few minutes. Since mine does not the pvc pipe will have to been cut and reorientated. Fix is scheduled for next Friday. He said it is safe to run in the mean time because if blockage occurs system will shutdown.

I may have had the same issue today.
Good timing.

Even with properly pitched piping and correct drainage there is condensation in the direct vent fan housing that could possibly be heard. Most of these housings have a drain opening in them that connects to a trap that all the furnace drain tubes also connect to before being piped to a condensate pump or drain line. If there were major condensation issues the pressure switch would lock out combustion. Some manufacturers offer another trap that gets installed in the horizontal exhaust vent as close to the furnace as possible, to keep much of the condensate from getting back to the furnace.

This is a condensing type furnace, which produces condensate which must be removed from the vent. The furnace is designed to be vented from either the right or left side of the unit. The condensate must be removed from the same side of the unit that the vent is connected to. If the unit has the vent on the opposite side of the condensate drain, it may cause the problem you are experiencing.