3.5 inches WC for a single stage furnace. 2 stage would be 1.75`` low fire and 3.5`` hi fire. For a modulating gas valve, follow the mfr`s set up instructions.
Negative pressure switch
Assuming the following typical conditions:natural gas manifold pressure is 3.5" w.c.propane manifold pressure is 10" w.c.natural gas and propane specific gravities are 0.6 and 1.52 relative to airnatural gas and propane energies per cubic foot are 1038 and 2516 BTUyour orifice coefficients are the samethen the propane orifice diameter should be 0.623 times the natural gas orifice diameter.
The pilot flame is/should be about 1.5" long, the diameter of a pencil. When the burners are going, the gas is shot into the burner manifold, and the gas sent to the burner is designed to go to the back of the heat exchanger. So, in a typical 80,000 input heater, about 14"-18" long.
an electric furnace runs off of 208/230 Volts while a typical gas furnace runs off of 120 also a gas furnace will have a valve for the gas relay where the gas enters the furnace.
120
When a typical residential furnace or gas package unit "high limit switch" is found to be bad it is replaced with a new one-not repaired.
This is the pressure supplied from the gas meter to a appliance this should be 20mb at the inlet of the gas valve before the appliance is working ie taking gas from the main pipe.
inreasing pressure
Drug peer pressure, peer pressure related with alcohol, sexual peer pressure, and even peer pressure to break the law, are some of the most typical ones.
increase the efficiency of the system
There is no typical number in mathematics.Usually any natural number. 1,2,3,4,5... and so on.
Air pressure, everywhere, varies day to day dependant on weather factors