A
G-TRAC2
IOM-25
24 of 42
Mar 99 R7
Ambient Based Discharged Air Set Point Reset Curves
In order for the discharge air temperature to go from zero reset to maximum reset,
(up or down)
the ambient temperature
has to change by 40°F.
Make/Break Resets and Overrides
1.
“OR” and “V” Override (Day Only)
DAY OPERATION ONLY
(Dipswitch A-3 should be on).
NOTE:
This will not operate with intermittent night blower, terminal “K” energized.
With the contact closed, discharge temperature is at 120ºF.
With contact open, discharge temperature is as per the set point dial plus any other
reset options values that are activated.
This simpler version of the make/break override options is the one that closes a contact between the G-TRAC terminals
"OR" and "V". This is designed to operate as an override for day operation and will drive the discharge temperature up to
120º when the contacts for the thermostat are closed. When the thermostat is not calling, the discharge temperature value
is that shown on the temperature set point dial
(either the G-TRAC mounted dial or the optional remote dial)
.
This set up is designed for a daytime override where you have the fan operating continuously. It does not respond to
terminal “K” for night heat operation. If you attempt to operate this as a night-time override, the heat cannot start because
the supply fan is not operating. Additional steps must be taken for night operation.
You can take the following additional steps to operate the control as a night heat package:
The "OR" and "V" operation looks for the fan to be running before it can start the heat. It has no internal method of
starting the fan.
If it is the intent to use this option as a night heat function, you must have the room thermostat operate a relay that
will close G-TRAC contacts "OR" and "V" as well as have a second set of contacts that will re-establish power to the "FS"
terminal.
When the "FS" terminal is powered, the G-TRAC will see that the fan is operating and it will bring on the heat to
operate at 120ºF-discharge temperature until the room thermostat is satisfied.
OR
V
Thermostat
or Contact
-20°F
0°F
20°F
40°F
60°F
80°F
Warmer Set Point
Maximum Up Reset
Ambient Temperature
Maximum Down Reset
No Reset
Cooler
