L.B. White Therma Grow HW120 Manuel De L'utilisateur page 20

Gas Pressure Checks
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The following explains a typical procedure to be
followed in checking gas pressures.
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Consult the dataplate on the heater or page 4 in this
manual for specific pressures to be used in
conjunction with this procedure. The gas pressures
will vary depending upon fuel type.
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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
(To be secured through local purchase)
Quantity Description
2 Gas pressure gauges capable of reading
up to 35 in. W.C. (may also be ordered
from L.B. White, part number 00764)
A. Preparation
1. Disconnect the heater from the electrical supply and
close the fuel supply valve to the heater inlet.
2. Open the case access panel at gas inlet end of
heater.
3. Brush or blow off any dust or dirt in the vicinity of the
gas control valve.
B. Gauge Installation
1. Locate the inlet and outlet pressure taps, see Fig. 16.
Remove the pressure tap plugs using a 3/16 in. allen
key.
2. Securely connect pressure gauges.
3. Open the fuel supply valves to the heater, reconnect
the heater electrical supply, and start the heater.
FIG. 16
OUTLET TAP
TYPICAL PRESSURE GAUGE INSTALLATION. ALWAYS
REFER TO DATA PLATE FOR FUEL TYPE AND
PRESSURE REQUIREMENTS.
C. Reading Pressures
1. With the heater operating, the pressure gauges
2. Do the readings at the inlet and outlet pressure
3. If the inlet pressures do not agree with that specified
4. If the inlet pressure is correct but the burner manifold
5. Turn the thermostat down to its lowest setting.
6. Slowly turn up the thermostat until the valve opens in
7. Turn the thermostat up to its highest setting. You
D. Completion
1. Once the proper inlet and burner manifold pressures
2. Disconnect the heater from its electrical supply.
3. Remove the gauges.
4. Install pressure tap plugs.
5. Open fuel supply valve. Start the heater and check
INLET TAP
6. Set thermostat to desired temperature.
should read the pressures specified on the dataplate.
gauges agree with that specified on the dataplate?
If so, then no further checking or adjustment is
required. Proceed to section D.
on the dataplate, then the regulator controlling gas
pressure to the heater requires adjustment.
pressure does not agree with that specified on the
dataplate, then the HI and LO heat output feature of
the gas control valve requires adjustment.
Remove the cap from the HI and LO heat adjusting
screws at the two stage pressure regulator on the gas
control valve.
first stage position. Verify first stage pressure by
information provided on the data plate or page 4 of
this manual.
should see the gas pressure increase to the second
stage gas pressure given on the data plate or in the
owner's manual. If proper pressure is not observed,
thenm the HI setting of the gas contol valve requires
adjustment.
have been confirmed and/or properly set, close the
fuel supply valve to the heater and allow the heater to
burn off any gas remaining in the gas supply line.
for gas leaks.
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