No suction at return air vent

[Bob Elliott]

Who cares if c/o is a little lighter or heavier ?

The function of a return is to "circulate"air (get it) and the return sucks the air in meaning the air is not static.

The return can also suck flue gas from the hood at the water heater.

[Christopher Currins]

Originally Posted by belliott

Who cares if c/o is a little lighter or heavier ?

The function of a return is to "circulate"air (get it) and the return sucks the air in meaning the air is not static.

The return can also suck flue gas from the hood at the water heater.

Or possibly from furnace flue.

[Charley L. Bottger]

Originally Posted by ccurrins

Or possibly from furnace flue.

Not going to pull Co from the furnace flu as its sealed but it sure will from the burner area its not sealed

[Christopher Currins]

Originally Posted by cbottger

Not going to pull Co from the furnace flu as its sealed but it sure will from the burner area its not sealed

So are these white mineral deposits just a sign of poor venting?

[Bob Elliott]

Originally Posted by ccurrins

So are these white mineral deposits just a sign of poor drafting?

Calcium type deposits are a sign of moisture (basement air) which also could be a poor fuel/air mix.

I always like banging on the B vent to make it snow when I see that.

Judging by the amount of rust on the inducer fan casing I am wondering about your how your flue terminates.Noticed the downturn by the way.
Does it go all the way or terminate in a regular brick/clay tile lined chimney that shares with the Water heater?

(edit) I just looked and noticed that home is less than 20 years old so it goes all the way however I see the tell tale green stains over at your condensate drain where it exits the casing.(tall basement)

[Christopher Currins]

Originally Posted by belliott

Calcium type deposits are a sign of moisture (basement air) which also could be a poor fuel/air mix.

I always like banging on the B vent to make it snow when I see that.

Judging by the amount of rust on the inducer fan casing I am wondering about your how your flue terminates.Noticed the downturn by the way.
Does it go all the way or terminate in a regular brick/clay tile lined chimney that shares with the Water heater?

(edit) I just looked and noticed that home is less than 20 years old so it goes all the way however I see the tell tale green stains over at your condensate drain where it exits the casing.(tall basement)

The house is just under 20 yrs. old, so is furnace. 9' ceiling in basement, raised ranch, 80% is finished, all but utility room, approx. 10'x15'. Yes vent does have short negative pitch.

[Charley L. Bottger]

The white calcium is from condensate running back down the flue. Flu gases condensing before they discharge the exterior. Slight possibility of rain water entering from the rain cap but not likely.

[Bob Elliott]

Originally Posted by cbottger

The white calcium is from condensate running back down the flue. Flu gases condensing before they discharge the exterior. Slight possibility of rain water entering from the rain cap but not likely.

Especially since the B vent has a drain trap built in ...eh Charlie.
Most likely a sign the air/fuel mix needs some adjusting unless the basement is super damp,after all the return is down there sucking it up.Would you agree "HVAC MAN" (opps gave your secret identity away).

[David A. Andersen]

Can you expound on your air/fuel mix thoughts?

[Bob Elliott]

Originally Posted by dandersen

Can you expound on your air/fuel mix thoughts?

Expound? (do you talk that way) lol

Just jerking the chain David because I am sure you already know that a bad fuel/air mix may cause to little of a heat/ rise which in turn causes condensate to form.
The inducer fan may not be enough to push it out before it condenses ,especially with the negative slope we see at the elbow what may be an extra long "B vent run" I suspect .