GAS FURNACE
Page 33
HARMONY IIIT ZONE CONTROL SYSTEM
Furnace System Start−Up & Checkout
IMPORTANT
The zone control system power−up must occur at the same
time or before the furnace or air handler unit is powered up.
Powering the System (All Systems)
1. Adjust all thermostat settings so that no demand will occur.
2. Apply power to the zone panel transformer and to the furnace and observe the following: all four diagnostic LEDs will
light; then each individual diagnostic LED will light in sequence; then all four diagnostic LEDs will light and extinguish.
3. Finally, the status light will begin to flash, indicating proper operation. Perform the gas heating checks on pages 33
through 34.
Gas Heating Checkout (Single Zone)
Prerequisites:
S Zone 1 thermostat set to Heat
OUTPUT STATUS LEDs
DAMPER 2,3,4 ON
DAMPER 1 OFF
W1 ON
(W) RED ON
HEATING ON
FAN ON
1. Set zone 1 thermostat for a heat demand; check:
D Zone 1 thermostat W LED on (heating demand).
D Damper 1 LED off (damper open).
D Damper 2, 3, and 4 LEDs on (dampers closed).
D Output Heat W1 LED on (furnace on).
D Heating LED on.
The furnace begins ignition sequence after zone 1 has
demanded heat. The zone control system will start the
furnace blower on low speed (0 PIAB) 45 seconds af-
ter the combustion cycle has begun.
2. When 100ºF warm air is sensed by the discharge air
sensor, the fan LED will light and the blower will slowly
increase to speed required by the zone calling. The
blower operates at speed setting of PIAB jumper for
zone 1 and the jumper for heating air reduction. It may
require 60 − 90 seconds to reach this speed.
3. Set zone 1 thermostat for NO heat demand; check:
D Zone 1 thermostat W LED off (no heat demand).
D Output Heat W1 LED off.
D Fan LED off.
D Heating LED off.
D Damper LEDs 2−4 remain on until after 3-1/2 min-
ute purge; then off.
To check the amount of air being delivered to each
zone and to confirm that each individual zone damper
functions properly, repeat these steps for zones 2 − 4.
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