Start-Up - 2:1 Electronic Modulation
1. Send Unit to High Fire
Turn the temperature | Temperature | |
selector to its maximum | ||
Selector | ||
setting to send the unit | ||
| ||
to high fire. |
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2.Check the High Fire Manifold Pressure
With the unit at high fire, use a manometer to measure the burner manifold pressure at the manifold pressure test port. See the Gas Train Layout in the Reference section for the manifold pressure test port location.
The recommended high fire manifold pressure is
Note
The low fire manifold pressure should always be rechecked after adjusting the high fire.
Note
Once the high and low fire manifold pressures are properly set, reset the discharge air temperature to the desired setting.
If needed, use the high fire adjustment screw on the
High Fire
Adjustment
3. Send Unit to Low Fire
Remove and isolate one wire from the modulating gas valve terminal to send the unit to low fire.
4. Check the Low Fire Manifold Pressure
With the unit at low fire, use a manometer to measure the burner manifold pressure at the manifold pressure test port. See the Gas Train Layout in the Reference section for the manifold pressure test port location.
The recommended low | 2:1 Manifold Pressure | |||
fire manifold pressure is | (in. wg) |
| ||
7/8 in. wg for |
| Natural Gas | LP | |
|
| |||
natural gas and | Low Fire | 7/8 | ||
2‑1/2 in. wg | ||||
High Fire | 10 | |||
for LP gas. | ||||
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|
| ||
If needed, use the low fire adjustment screw on the
modulating gas valve to adjust the low fire manifold | ||
pressure. Counterclockwise | Terminal | |
rotation will decrease the | ||
| ||
gas pressure and clockwise |
| |
rotation will increase the gas |
| |
pressure. |
| |
Once the low fire is set, reattach the disconnected wire to the modulating valve
and reset the temperature Low Fire
selector.
®
Adjustment
Model IG / IGX
