Looking for small/cheap wall mounted boiler that has cascading vent

baltik

I have a very small heat load and was looking at the rinnai m-series as well as IBC HC-13-50. One feature that would be really nice to have is a cascading venting option so I can tie into my existing 2” exhaust line that’s setup for my navien npe. Any ideas?

GGross

You are almost definitely not going to be able to common vent 2 boilers in a 2" flue. I would be shocked if any condensing manufacturers approved common venting their equipment with other brands of equipment at all, most require that common vents only contain identical pieces of equipment.

baltik

Got it, would upsizing to 3” change that?

GroundUp

I think you can common vent Navien appliances together (at least you can with multiple boilers), but certainly not with 2" pipe. Check into Navien's literature and see what you can find there

EBEBRATT-Ed

Best to keep them separate to avoid warranty and other issues.

EzzyT

Common venting can only be done as per manufacturers specifications with same model and sized equipment. You are not allowed to common vent a boiler and tankless water heater.