The four types of gas furnace air flow patterns are?
Upflow, downflow, horizontal left and horizontal right.
What is the function of a multipoise or multipositional furnace?
Multipoise or multipositional furnaces can be installed in any position.
What is the function of a draft safeguard switch?
A draft safeguard switch are normally closed(NC) switches that monitor the draft hood temperature. They open when there is a spill of flue gas and they are usually mounted on the draft hood.
Where are the auxiliary limit switches used in heating applications?
Auxiliary limit switches monitor room return air temps and interrupt burner operation when the temperature gets too hot. They are used for counterflow and horizontal furnaces and are located on the warm air blower housing.
The specific gravity of natural gas is?
The specific gravity of natural gas is 0.60
What is a water and digital manometer?
A water or digital manometer is an instrument that measures gas pressures.
The pressure at the manifold for natural gas is?
The pressure at the manifold for natural gas is normally 3.5" WC (water column).
What is the approximate oxygen content of air?
The approximate oxygen content of air is 21%.
The typical manifold pressure for propane gas is?
The typical manifold pressure for propane gas is 27.7 in WC
Why is excessive air supplied to all gas burning appliances?
Excessive air is supplied to all gas burning appliances to support combustion.
The purpose of a gas regulator at a gas burning appliance is to?
The purpose of a gas regulator at a gas burning appliance is to drop the pressure to the proper level (in. WC) and maintain this constant pressure at the outlet where the gas is fed to the gas valve.
Do all gas valves snap open and closed?
Which features does an automatic gas valve have?
An automatic gas valve has a pressure regulator, pilot safety shutoff and a redundant shutoff feature.
What is the function of the servo pressure regulator in a modern combination gas valve?
The servo pressure regulator closely monitors the outlet or working pressure of the gas valve. Any gas outlet pressure change is instantly sensed and reflected back to the diaphragm. The servo pressure regulator then repositions its diaphragm and disc to change the flow rate.
What is a redundant gas valve?
A redundant gas valve has two or three valve operators physically in series but wired in parallel with one another. This built in safety feature allows any operator (pilot or main) to block gas from getting to the main burner.
What is a intermittent pilot gas valve system?
An intermittent pilot gas valve system lights the pilot every time there is a call for heat by the thermostat. When the call for heat ends the pilot is extinguished and does not relight until the next call for heat.
What is a direct burner gas valve system?
In a direct burner gas valve system the electronic module or IFC lights the main burner directly without a pilot flame. A spark, hot surface igniter or a glow coil ussually accomplishes ignition.
Where are inshot burners used in heating applications?
Inshot burners simply slip over the orifice spuds and are screwed in place.
What is an integrated furnace controller (IFC)?
An integrated furnace controller controls the ignition and sequence of operation of most modern gas furnaces.