52
5.2.3.3. Typical Dual Fuel Gas Heating (Central Mode)
Prerequisites
:
• Central mode switch on.
• Red LED on the central mode fan switch on.
• Zone 1 thermostat set to Heat.
9
Balance Point Sensor set at higher temperature than outdoor BPS-
sensed temperature (red balance point sensor LED on) or
9
Balance Point Sensor inputs jumpered to simulate cold outdoor
temperature below balance point (red balance point sensor LED on).
.
OUTPUT STATUS LEDs
DAMPER 2,3,4 OFF
(W) RED ON
HEATING ON
FAN ON
W1 ON
1.
Set zone 1 thermostat for a heat demand; check:
• Zone 1 thermostat
W
LED on (heating demand).
• Output Heat
W1
LED on (furnace on).
• Heating LED on.
• All damper LEDs off (damper open).
2.
The furnace will begin its ignition sequence after Zone 1 has demanded heat. The
zone control system will start the furnace blower on low speed (0 PIAB air) 45
seconds after the combustion cycle has begun.
3.
When 100ºF warm air is sensed by the discharge air sensor, the fan LED will light
and the blower will slowly increase to speed. The blower will operate at a speed
equivalent to the PIAB calculated for all zones calling, taking into account the
heating air reduction jumper position. It may take the blower 60 to 90 seconds to
reach this speed.
4.
Remove the heat demand from zone 1 (no heat input or output and no blower
demand). Upon removal of the demand from zone 1, check:
• Zone 1 thermostat
W
LED off (no heat demand).
• Output Heat W1 LED off.
• Fan LED off.
• Heating LED off.
After 3-1/2 minute purge time, furnace blower turns off.
Summary of Contents for Harmony III
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