Page 19
HARMONY III
T
SERIES
onds starting with the most recent code, then the next most
recent, and so on. Pressing the button while recalling fault
codes will bypass the 10-second timer and go right to the
next fault code.
Use the Fault Recall button to observe diagnostic codes
that will indicate either correct operation, or help checkout
and troubleshoot problems in the zone control system.
Table 10 in the troubleshooting section (see page 25) iden-
tifies all diagnostic codes.
Press the button once while the system is operating. The
system will respond by momentarily lighting all four DIAG
LEDs then displaying the error code, if an error code is
stored in memory. This allows a visual check to verify that
all four LEDs are operational before displaying an error
code.
Time Delays
Timers used in the Harmony III
t
system define delays
which precede or follow a demand, depending on the type
of function. The delays are used to control equipment con-
nected to the system. Table 9 shows how the most notice-
able delays are used.
New System Start−Up & Checkout
Powering the System (All Systems)
Adjust all thermostat settings so that no demand will occur.
Apply power to the furnace and to the zone panel trans-
former 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 extin-
guish. Finally, the status light will begin to flash, indicating
proper operation. Perform the gas and heat pump heating
checks on pages 20 through 24.
Table 9
Time Delays
Delay
Time
Function
Blower Off Delay (gas heat only)
3-1/2 min.
Gas Furnace only. Dumps air into last zone called during cool down following heat demand.
Compressor Speed Change
4 min.
Between low speed and high speed in order to make sure steady state is reached before stag-
ing.
Compressor Off Time
5 min.
At end of demand. Equalizes pressure in refrigerant system and prevents short cycling.
Heat Staging (electric)
2 min.
Between staging up or down (May stage faster to prevent overshoot/undershoot).
Heat Staging (gas)
3 min.
Between staging up or down to achieve steady state.
Dual Fuel Furnace Lock-in Timer
3 hrs.
Starts when system enters dual fuel furnace heating when the outdoor temperature is above
balance point. When operating within this 3-hour time, only the furnace is used for heating. Heat
pump will be tried again on the next call after this timer expires. Diagnostic LEDs 2, 3, and 4 will
flash when this timer is active.
Damper Hold
3-1/2 min.
This timer is defined as the amount of time to hold the last zone calling open past the thermostat
call drop out. During this time, the panel will not energize the blower (except when a continuous
fan call exists); the controlled equipment will provide this signal. This is a non−adjustable timer
set at 210 seconds.
Autochangeover
20 min.
When opposing demands are present, zone control system must work to satisfy current demand
at least 20 min. If current demand is not satisfied after time has elapsed, system will changeover
and satisfy opposing demand. On and Off delays above will also apply.