Specifications

If the Time Guard Between Modes option is configured
OFF, the length of the Time Guard is approximately
30 seconds.
The Time Guard Override option may be used to over-
ride the Time Guard to 30 seconds for one cycle. To ac-
tivate the override, toggle category 4, option 3 ON and
then OFF.
5. The monitor thermostat system mode demand (minimum
number of callers required to select a system mode) must
be equal to or less than the number of zones calling for
a particular mode. The number of callers for each mode
can be determined by setting the Alternate Information
option (category 7, option 3) of the monitor thermostat to
ON. Alternate Information display items 13 and 14 show
the number of heat callers and cool callers respectively.
Alternate Information display item 15 shows the refer-
ence zone address.
6. Check the monitor thermostat display for a flashing HEAT
or COOL annunciator. A blinking annunciator indicates a
supply-air temperature problem.
7. Ensure the monitor thermostat is free of possible HF (Hard-
ware Failure) or SF (Storage Failure) errors that can lock-
out the ability of the monitor thermostat to energize
supplemental heat. HF and SF errors will be displayed on
the monitor thermostat if the Error Code Display option
(category 7, option 1) is configured to ON.
8. Check the configuration of the monitor thermostat
System Heating Mode Lockout, Heating Lockout Tem-
perature Set Point, and Cooling Lockout Temperature Set
Point options. Based on the outside air temperature, the
monitor thermostat can lock out either system cooling or
heating modes.
MONITOR THERMOSTAT FAILS TO ENERGIZE SEC-
OND STAGE — When the monitor thermostat fails to en-
ergize the second stage of the heating or cooling equipment,
check the items that affect the decision of the monitor ther-
mostat to energize the second stage of heating or cooling.
1. When the monitor thermostat Optimize Staging function
(category 4, option 10) is configured to ON, the monitor
thermostat will energize the second stage of heating or
cooling only after it determines that the reference zone
demand is not being met by the first stage of heating or
cooling.
If the Optimized Staging function is configured off, the
monitor thermostat will energize the second stage 3 min-
utes after the first stage, if the demand of the reference
zone is equal to or greater than 2° F.
2. Set the Alternate Information function (category 7,
option 3) of the monitor thermostat to ON. Check the moni-
tor thermostat display for a flashing HEAT or COOL an-
nunciator. A blinking annunciator indicates a supply air
temperature problem.
ANNUNCIATOR DISPLAYED BUT EQUIPMENT NOT
ENERGIZED — The monitor thermostat HEAT or COOL
annunciator is ON, but the heating or cooling equipment is
not energized.
Check the monitor thermostat Auxiliary Relay option
(category 4, option 9). If the monitor thermostat is config-
ured to operate an economizer, the monitor thermostat will
enable the economizer for first stage cooling when the out-
side air temperature is less than 64.9 F.
Check the LEDs on the relay pack controlled by the moni-
tor thermostat. Perform the correct procedure.
LED NOT LIT— The monitor thermostat HEAT or COOL
annunciator is ON but the LED on the relay pack is not lit.
1. At the damper actuator, unplug the relay pack and check
the voltages between the damper output PIN 1 (common)
and PIN 5 (H1). There should be approximately 7.5 to
9.5 vdc (steady). If the monitor thermostat has selected
second stage heat (indicated by the dot on the monitor
thermostat display), the voltage between PIN 1 (com-
mon) and both PIN 5 (H1) and PIN 6 (H2) should be
between 7.5 and 9.5 vdc. If not, replace the damper ac-
tuator circuit board.
2. At the damper actuator, with the relay pack plugged in,
check the voltages across the relay pack input connector
plug. Voltages should read approximately 4 to 6 vdc
(steady) between the black wire and the appropriate relay
pack input wire. If not, replace relay pack.
LED IS LIT — The monitor thermostat HEAT annunciator
is ON, the LED on the relay pack is lit, but the correspond-
ing equipment stage is not energized.
1. Check the AC voltage across the relay board common (red)
and any deenergized relay (H1 or C1 in Fig. 33). The volt-
age should read 24 vac. If not, check for wiring error.
2. Check the AC voltage across the relay board common (red)
and any indicated energized relay board output. The volt-
age should read near zero (<1 vac). If 24 vac is read, check
for bad relay board.
3. Check the AC voltage across a suspected contactor coil.
The voltage should read 24 vac. If not, check the con-
tactor coil wiring.
4. Other possibilities are: bad contactor, defective equip-
ment, or no unit power.
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