[jeremy1375]

I installed a ventless heater a couple years ago. The supply coming into my house is 2 psi. The heater will list specifications for gas pressure. IIRC, the specs for input pressure on mine mine were 5-10.5" inches of water. I had to install a regulator and put together a diy manometer to set the pressure. The heater won't work right if the pressure is wrong.