Wet Return Line Size

fxrgrunt

Good morning. My wet return was redone when the boiler was done before I lived in this house. It was done with copper but with no clean outs. I know copper is fine for wet returns but being I wanted to do clean outs anyways I may just install black pipe. My question is what size pipe would be proper for a wet return back to the boiler? My boiler is 150k btu. It runs to 2 separate 2" mains that are 66ft and 47ft long and drop down into the wet return on the end. 

Jamie Hall

Inch and half or two inch will be ample.

EBEBRATT-Ed

It depends on the load on the main that is connected to that wet return you are replacing.

Add up the EDR on that main

From the Burnham Heating Helper

Wet Returns

1" 900 EDR
1 1/4" 1530
1 1/2" 2430
2" 5040

You shouldn't use anything smaller than 1" on a wet return as they tend to plug up.

What is wrong with the pipe size yo have now?

mattmia2

More importantly, the copper won't rot out the way iron will.

fxrgrunt

EBEBRATT-Ed said:

It depends on the load on the main that is connected to that wet return you are replacing. Add up the EDR on that main From the Burnham Heating Helper Wet Returns 1" 900 EDR 1 1/4" 1530 1 1/2" 2430 2" 5040 You shouldn't use anything smaller than 1" on a wet return as they tend to plug up. What is wrong with the pipe size yo have now?

I think it's 1 inch copper. I feel like the water isnt getting back to the boiler fast enough being my lwco kicks on occasionally. Not sure if it's due to the surging being the near boiler piping is too small or the wet return is plugged up/too small. I do need to install clean outs and isolation valves on the wet return at the very least.

mattmia2

It is more likely that you have issues that are causing wet steam or dry returns or radiators that have pitch problems than the wet return is slowing it down.