Greenheck IG / IGX (464104 IOM) (Pre-2009) - Manual (Page 36)

36
High Fire
Adjustment
Low Fire
Adjustment
High Fire
Terminal
Start-Up - 2:1 Staged Control
Step 1 Send Unit to High Fire
Send the unit to high fire by setting the temperature
selector to its maximum setting.
Step 3 Send Unit to Low Fire
Remove and isolate the wire from the high fire terminal on the combination gas valve to send the unit to low fire.
Step 2 Check the High Fire Manifold Pressure
Using a manometer, measure the burner manifold pressure at the manifold pressure test port. Refer to the gas
train layout in the reference section for the test port location.
The pressure on high fire should be 3 1 ⁄
2
inches wc for natural gas and 10 inches wc for LP gas.
If needed, use the high fire adjustment screw on the combination gas valve to adjust the high fire manifold
pressure. Counterclockwise rotation will decrease the gas pressure and clockwise rotation will increase the gas
pressure.
Step 4 Check the Low Fire Manifold Pressure
Using a manometer, measure the burner manifold pressure at the manifold pressure test port. Refer to the gas
train layout in the reference section for the test port location.
The pressure on low fire should be 7 ⁄
8
inches wc for natural gas and 2 1 ⁄
2
inches wc for LP gas.
If needed use the low fire adjustment screw on the combination gas valve to adjust the low fire manifold
pressure. Counterclockwise rotation will decrease the gas pressure and clockwise rotation will increase the gas
pressure. Once the low fire manifold pressure is set, reattach the high fire wire to the high fire terminal.
Step 5 Reset the Temperature Setting
Reset the temperature setting on the temperature selector to the desired setting.
Two Stage Manifold
Pressure (inches wc)
Natural Gas LP
Low Fire 7 ⁄
8
2 1 ⁄
2
High Fire 3 1 ⁄
2
10
Temperature
Selector
Start-Up