Help!! Regulator problem or bad gas?

MnBen

Same tank... two furnaces, one in the garage and one in the house. Both started short cycling at the same time. The gas company replaced the high pressure regulator at the tank...did not fix the issue. 

When there is a call for heat in the house pressure drops “significantly” at the low pressure regulator on the house, the furnace inside (York diamond 80) ignites until the blower kicks in and then loses flame... 

Garage: the big max mr heater (brand new and was converted to propane) ran great until it didn’t!. It continues to short cycle but runs a few minutes before dying. 

This is way to coincidental... 

rick in Alaska

The only way to tell would be to put a pressure gauge on the line before the low pressure regulator, and one after it and see how they respond when you run anything. The pressure shouldn't drop much. Could be the low pressure regulator is defective.
Rick

Zman

Is this a new construction?
What are the BTU ratings on the appliances.
Most buildings with a significant load have a regulator at the tank and and regulator at the building. This is to eliminate the pressure drop issue in the smaller underground line.

MnBen

Not new construction... house was built in 1900 but the garage was just redone. Both structures have a low pressure regulator at the house. 80k 

Solid_Fuel_Man

Ok, so you have one first stage regualtor at the tank and that serves two second stage regulators? One for that garage and one for the house? 

Are there two pipes coming out of the first stage reg at the tank? 

EBEBRATT-Ed

You need to check piping and regulator sizing. Also the size of the tank is important. A small tank in cold temps will not vaporize enough gas to keep up. It can freeze up regulators