LOW PRESSURE GAUGE
OUTLET PRESSURE TAP
INLET
PRESSURE
TAP
ON
OFF
0
.50
1.00
2.00
1.50
2.50
3.00
3.50
1. Brush off any accumulation of dust that may be
found.
2. Check manifold gas pressure with a low pressure gas
gauge:
a. Shut off the gas supply to the heater.
b. Disconnect the heater from its electrical supply.
c. Remove the metal cover from the control valve
enclosure.
d. Turn the screw in the pressure tap at the outlet of
the valve counterclockwise a minimum of one full
turn.
e. Connect a low pressure gas gauge to the pressure
tap.
f. Open fuel supply and reconnect heater to electric
supply.
g. When heater lights, the gas gauge will read 2.50
KPa - LP or .75 KPa - Natural gas pressure. This
pressure is the flowing gas pressure necessary for
the heater to deliver maximum output. If the
gauge does not indicate proper manifold pressure,
check inlet pressure to the gas control valve.
Maximum and minimum acceptable inlet
pressures to gas control valve are shown in the
heater specifications table (See page 4.) and on
the heater’s dataplate The inlet pressure may
need adjustment as necessary to achieve proper
manifold pressure. Inlet pressure is checked in
the same manner as outlet pressure.
h. After pressures have been checked, shut off the
gas supply and electrical supply to the heater,
remove the gauge, and tighten the pressure tap
securely. Open gas supply and reconnect the
heater to its electrical supply.
3. Reinstall the metal cover.
FIG. 11
GAS CONTROL VALVE
WARNING
Fire and Explosion Hazard
■
Do not disassemble the gas control valve.
■
Do not attempt to replace any components on 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 fire or
explosions, leading to injury or death to humans and
livestock, and building damage.
The high limit switch should be tested a minimum of once
per year when the heater is given a thorough cleaning.
1. Disconnect the heater from its electrical supply.
2. Remove the high limit switch from the heat chamber.
3. Holding the switch by one of its mounting legs or
electrical terminals, apply a small flame only to the
sensing surface on the back of the switch.
Be
careful not to melt the plastic housing of the switch
when conducting this test.
4. Within a minute, you should hear a “pop” coming
from the switch, which indicates the contacts of the
switch have opened.
5. Allow the switch cool down for about a minute before
firmly pressing the red reset button on the switch.
6. Check for electrical continuity across the switch
terminals to make sure the contacts have closed.
7. Reinstall the switch back into the heater. Reconnect
the heater to its electrical supply. Start the heater
and check for proper operation.
FIG. 12
TESTING THE MANUAL RESET HIGH LIMIT SWITCH
WARNING
Fire Hazard
■
Do not operate the appliance with the high limit switch
bypassed.
■
Operating the heater bypassed high limit switch may
lead to overheating, possibly resulting in a fire, with
subsequent damage to the heater, building damage, or
loss of livestock.
RESET BUTTON
SENSING
SURFACE
TERMINAL
FLAME
MOUNTING
LEG
16
