Burying copper wet return in gravel basement floor - questions

Ramori

Had a new boiler installed recently. Contractor also replaced the copper return line, because the original return line had cracked due to another contractor who damaged it while replacing support posts for the floor beam above (another story for another time!).

Contractor ran the new copper return line in a trench dug in the gravel floor, and they recommended lining the trench with lengths of aluminum gutter, running the copper in the gutter, placing another gutter over the top upside down, then backfilling the gravel. This should make it easier to access the pipe if I need to in the future. See photo.

After a hard rain, water can seep up from the ground, and the gravel floor can hold a LOT of water. We got about 3 inches of rain last night (Vermont) and this morning, the gutter was filled with water, which immediately turned to steam as the hot return pipe is laying in this groundwater-filled gutter. The entire basement was full of steam! Like a Swedish sauna. I hadn't backfilled/buried the line yet, so the rain water steam easily filled the basement. I'm worried that the steam/humidity could damage the hardwood floors above.

Question: Once I put the gutter cover on, and bury/backfill with gravel, do you think the basement will steam up again, when i get more heavy rains in the future? Or will the gravel on top, dissipate any steam that's created in the flooded gutter?
Should I insulate the copper pipe to reduce the external pipe temperature, so the groundwater won't turn to steam? Is the general idea of the gutter, a good idea or a bad idea?

We didn't have this issue with the old return line, as it was buried directly in the gravel, about 8 inches down (in the 1920's)

KC_Jones

Run the pipe above the floor, along the wall so it's out of the way.

The gutter is, well it's a hack job honestly. They literally make in floor trenches with grate covers to do this. I believe, but not positive, they are water tight so they stay dry from the outside. Even with that I would run it above the floor.

Given what I see in the picture, this set up is going to be problematic forever unless you can stop the water intrusion entirely.

Jamie Hall

I agree with @KC_Jones , but... why is the condensate so hot? Check all the traps... you may be getting steam somewhere in a return which you don't want.

EBEBRATT-Ed

Running it on top of the floor would be better. But maybe you can't as I am sure you wouldn't have dug up the floor for nothing.

Any insulation put on the pipe will be saturated with water and I agree with @Jamie Hall it doesn't seem like the condensate should be hot enough to make steam.

I hate to mention this but maybe a condensate pump where the pipe goes under the floor and move the copper line to overhead and pump it back to the boiler.

ChrisJ

Jamie Hall said:

I agree with @KC_Jones , but... why is the condensate so hot? Check all the traps... you may be getting steam somewhere in a return which you don't want.

There's times when my return along the floor gets pretty hot.
Especially if it's below zero every night all week long since I have everything else insulated.

I don't think in this case it would need to be literally boiling hot to cause what they're seeing though. Imagine a basement that's now damp and the dirt is mud and that pipe is heating the water. Even 100F water will cause higher humidity. 150F would probably be enough to make it absolutely miserable.

That said....
My return right now isn't even warm. But, I wanted to mention I don't think it really needs to be that hot to turn that into a big humifier and make a bad situation worse.

Waher

Aluminum in contact with the copper is going to lead to a galvanic failure.

Trench products like this would be good idea:
https://www.balcousa.com/product-category/trench-and-access-covers/trench-covers/

It could be covered with mineral wool insulation which doesn't have the same problems as glass fiber insulation with ground contact.

ethicalpaul

I hate to hear mentioned a condensate pump, Ed!

realliveplumber

Get rid of the gutter, insulate the pipe with armaflex or rubatex, and backfill it.

Big Ed_4

I guess the only reason for the rain gutter which is a good one is for expansion, over time with friction. Which would wear out the pipe.

I would run minimum "L" pipe and cover with Armorflex before you bury it again .

With the water problem .... Vermont ? I assume run off . Check out French drains before you finish the area...

ChrisJ

I'm down with KC run the pipe over the floor out of the way.

ethicalpaul

With the wet return flowing through x feet of waterlogged trench, you will lose a lot of heat to the cold ground