Greenheck PVF/PVG Indirect Gas-Fired Heat Modules (474645) - Manual (Page 19)

Indirect Gas-Fired Heat Modules 19
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1. Connect a manometer to either test port on the
burner manifold.
2. Send the unit to high fire.
3. Check the gas pressure at the manifold test port. The
recommended pressure is 3.5 in. wg for natural gas
or 10.0 in. wg for LP gas.
4. Adjust the high fire screw on the valve
that is connected to the port being tested.
Counterclockwise rotation will decrease the gas
pressure and clockwise rotation will increase the
pressure.
5. Send the furnace to low fire by disconnecting and
isolating the wire from the high fire terminal on the
valve.
6. Check the gas pressure at the manifold test port.
The recommended low fire manifold pressure is
7/8 in. wg for natural gas or 2.5 in. wg for LP.
7. Adjust the low fire screw on the valve being tested.
Counterclockwise rotation will decrease the gas
pressure and clockwise rotation will increase the gas
pressure.
With 8 Stage Combustion
IMPORTANT
8 staged turndown furnaces use a split burner
manifold and two 2-stage gas valves per furnace.
The high fire and low fire manifold pressure must be
checked and properly set on each manifold.
Two Stage
Valve
Two Stage
Valve
Split Burner
Manifold
Remote Temperature
Sensor
FX Controller
Ignition
Controller
8. Turn off furnace. Reconnect the wire to the high fire
terminal. Remove manometer and reinstall plug into
manifold test port.
9. Connect manometer to the other manifold test port
and repeat the high fire / low fire set up sequence on
the other gas valve.
10. Turn off furnace. Reconnect the wire to the high fire
terminal. Remove manometer and reinstall plug into
manifold test port.
11. Return to the normal operation.
1. Connect a manometer to the test port on the burner
manifold.
2. Send the unit to high fire.
3. Check the gas pressure at the manifold test port. The
recommended pressure is 3.5 in. wg for natural gas
or 10 in. wg for LP gas.
4. Adjust the high fire screw on the valve.
Counterclockwise rotation will decrease the gas
pressure and clockwise rotation will increase the
pressure.
5. Turn off furnace. Remove manometer and reinstall
plug into manifold test port.
6. Return the unit to normal operation.
Single Section
Burner Manifold
Single Stage
Valve
Remote Temperature
Sensor
A350
JOHNSON
CONTROLS
A350
Controller
Ignition
Controller
With Single Stage