Condensation in stack

[Bricklayer]

After installing my new evaporator about a month ago. I’ve been noticing that I’m getting condensation inside the main chimney stack. It’s running down the inside of the stack and looking at the base.
Is this normal. ?
It came with the flapper lid for the top of the chimney. So I leave it closed.
I know it’s not getting in from rain because it’s all sealed up on the outside and pipes are tightly installed together.
Should the cap have some kind of spacer that leaves it open a tiny bit to let air circulate ?

The sugar house is not heated or cooled So it’s not like there is warm air trying to escape through the chimney or cool air.

[tcross]

could it possibly be rain coming in from the collar on your roof jack? mine doesn't fit tight enough where the two pieces bolt together to keep rain out. when it rains it drips down the chimney onto the base stack. in the off season i put a bead of silicone around that spot and it fixes it. took me a while to figure out where the water was coming from.

[nhdog]

i don't think your storm collar could in anyway cause water to enter the inside of the stack. the water would have to come in through the rain cap or possibly though the stack it self. it is possible that water could be entering at the pipe connection. if the female end is pointed up and the male placed down, water will run down along the out side of the stack until it hits the connection and find a way in if not properly seated. stacks in home wood stoves are just the reverse to keep creosote from running down the out side the pipe in side the house. your stack temps prevents creosote from ever being a problem.

[Bricklayer]

All my joints are male side up with female overtop. So no water is getting in that way.
It’s all on the inside of pipe and not when it rains. Had a full week of sunshine and no rain and still had water inside dripping down inside stack and pooling at bottom of base.

[Bricklayer]

It’s definitly condensation. I cleaned it last night bone dry. And was wet again tonight with no rain at all.
Weird.

[nhdog]

your evap is new and has been bricked. did the mortar have a chance to dry properly ? also is the evap completely closed up ? i keep my pan up off the rails on 2x4's and leave the fire box door open, this lets the air flow through. this might be something for you to look at.

[Bricklayer]

Yup. Fire brick is new, have had a couple fires in the evap to cure mortar and dry out any moisture remaining in brick. Evap is new.
Door is open , both front pans are off , so arch has lots of circulation.
But no draft going through as the flapper on top of the chimney is closed.
Was wondering if it would be better to have some holes drilled into the top of the pipe where the flapper sits. This way it would keep water out. But let some draft by

[nhdog]

i wouldn't dare make a suggestion about that. i ran insulated pipe from thru the roof on up and have a rain cap. i was afraid that the cap might reduce my draw but i still maintain good stack temp so i don't worry about it.