myredracer wrote:
Do holes in the floor need to be sealed up? There is a hole next to our furnace for the ducts into the underbelly space and it's big enough to throw a cat through it. Plus there are various holes for plumbing into the underbelly.
Is there a suggested CFM? We have two Fantastic fans and it would be nice if that does the job.
I want to start doing this annually. I like the idea of using a pass-through door opening.
I guess I would seal any big holes up permanently just for rodent control if nothing else. For performing the test, jam a rag in there. The places where the pressurised air can go is through ceiling vents, heater intake and exhaust, air conditioner plenum, vent fan duct, and through plumbing into vents or tanks.
I'd suggest to cover up the easy ones and don't sweat the small stuff. We're not trying to make the RV launch into the vacuum of the high atmosphere. I cover the vents with cardboard and install the sink stoppers. The truth is, with a blower that can deliver enough volume to raise the pressure 1" WC, even the escaping air out of windows and doors won't be a significant factor.
I've shown my method before, the furnace blower in a window. I think, for the RV'er that wants to DIY, introducing air from the outside through a storage hatch where there is am access to the inside or through a window is the easiest. You can get crazy and make adaptors to fit a ceiling vent or get all scientific and pull the air in through a vent like sealtech does but the bottom line is moving enough volume in to achieve .5"->1.5" WC. A simple DIY manometer can be made and attached to the board or plate used to mount the blower output. I used 1/2" vinyl tubing, made a loop and attached it to a piece of plywood. I filled it to equilibrium with blue food coloring and water.
Harbor Freight sells this
ventilator for $80 and I'm preety sure it will move enough for most RV's
