L.B. White Therma Grow HW120 Manuel Du Propriétaire page 21

B. Gauge Installation
1. Locate the inlet and outlet pressure taps, see Fig.
18. 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.
Plus model gas valve shown
FIG. 18
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
should read the pressures specified on the dataplate.
2. Do the readings at the inlet and outlet pressure
gauges agree with that specified on the dataplate?
If so, then no further checking or adjustment is
required. Proceed to section D.
3. If the inlet pressures do not agree with that specified
on the dataplate, then the regulator controlling gas
pressure to the heater requires adjustment.
Plus Models
1. If the inlet pressure is correct but the burner manifold
pressure does not agree with that specified on the
datatplate, then the HI and LO heat output feature of
the gas control valve requires adjustment.
2. Turn the thermostat down to its lowest setting.
Remove the cap from the HI and LO heat adjusting
screws at the two stage pressure regulator on the
gas control valve. See Fig. 18 for regulator location.
Therma Grow™ Greenhouse Heaters
3. Slowly turn up the thermostat until the valve opens
in first stage position. Verify first stage pressure by
information provided on the data plate or page 4 of
this manual.
4. Turn the thermostat up to its highest setting. You
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,
then the HI setting of the gas contol valve requires
adjustment.
Standard Models
• If the inlet pressures are correct and the burner
manifold pressure does not agree with that specified
on the dataplate, then the gas control valve's internal
pressure regulator requires adjustment. See Fig. 19
for regulator location.
D. Completion
1. Once the proper inlet and burner manifold pressures
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.
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
for gas leaks.
6. Set thermostat to desired temperature.
Owner's Manual • Therma Grow™
21