Gas Pressure Checks
(Single stage valve shown)
■ The following is a typical procedure to be followed
in checking gas pressures.
■ Consult the dataplate on the heater or page 4 in
this manual for specific pressures.
■ 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
MATERIALS REQUIRED
Quantity Description
2
Gas pressure gauges capable of reading
up to 35 in.W.C. (may also be order from
L.B. White, part number 00764)
1
Bushing, 1/2 in.x 1/8 in.
1
1/8 in. barbed fitting
1
3/16 in. allen key
A. Preparation
1. Disconnect the heater from the electrical supply
and close the fuel supply valve to the heater inlet.
2. Remove the lower nipple and cap from the
sediment trap and install the bushing and 1/8 in.
NPT barbed fitting. See Fig. 24.
FIG. 24
BUSHING
1/8" NPT BARBED
FITTING
3. Open the burner box access panel.
Sentry Tube Heaters
4. Remove either the inlet or outlet pressure tap. See
Fig. 25.
FIG. 25
OUTLET
PRESSURE TAP
5. Remove the air inlet tube from the burner box and
route the gauge tube through the air inlet to the gas
control valve. See Fig. 26.
FIG. 26
GAUGE
TUBE
6. Attach pressure barb and hose to either the gas
valve inlet or outlet to measure gas pressure.
Securely tighten the pressure barb. See Fig. 27.
FIG. 27 (SINGLE STAGE)
GAUGE
OUTLET
PRESSURE TAP
B. Reading Pressures
1. With the heater operating, the pressure gauges
should read the pressures specified on the
dataplate. See Fig. 31.
2. Do the readings at pressure gauges agree with that
Owner's Manual • Sentry
INLET PRESSURE
TAP
AIR
INLET
PRESSURE
GAUGE
GAUGE
TUBE
INLET
PRESSURE TAP
INTERNAL PRESSURE
REGULATOR CAP
23