Gas Pressure Checks
WARNING
■ Do not disassemble the gas control valve.
■ Do not attempt to replace any components of
the gas control valve.
■ The gas control valve must be replaced if any
physical damage occurs to the control valve
assembly.
■ Failure to follow this warning will result in fi re
or explosions, leading to injury or death to
humans, and property damage.
■ The following explains a typical procedure to be
followed in checking gas pressures.
■ The gas pressures will vary depending upon fuel
type.
■ Consult the dataplate on the heater or page 4 in this
manual for specifi c pressures to be used in conjunc-
tion with this procedure.
■ Gas pressure measured at the inlet to the gas valve
is Inlet Pressure and gas pressure measured at the
outlet of the gas valve is Burner Manifold Pressure.
A. Preparation
1. Obtain two pressure gauges capable of reading up
to 35 in. W.C.
2. Disconnect the heater from the electrical supply and
close the fuel supply valve to the heater inlet.
3. Open the burner access panel.
4. Brush or blow off any dust and dirt on or in the vicin-
ity of the gas control valve.
B. Gauge Installation
1. Locate the inlet and outlet pressure taps, see Fig.
25. Using a small standard screwdriver, open the
pressure taps by turning both screws one full turn
counterclockwise.
Guardian with Smart Sense™
FIG. 25
OUTLET PRESSURE TAP
2. Securely connect a pressure gauge to each
pressure tap. See Fig. 26
FIG. 26
3. Open the fuel supply valves to the heater and
reconnect the heater electrical supply.
4. Start the heater
C. Reading Pressures
1. Set the building controller to call for maximum
temperature. With the heater operating, the
pressure gauges should read the pressures
specifi ed on the dataplate.
2. Do the readings at the inlet and outlet pres-
sure gauges agree with that specifi ed on the
dataplate? If so, then no further checking or
adjustment is required. Proceed to section D.
3. If the inlet pressure does not agree with that
specifi ed on the dataplate, then the regulator
controlling gas pressure to the heater requires
adjustment.
Owner's Manual • Guardian
INLET PRESSURE TAP
25