A G-TRAC2 MANUAL
General Manual Revised: 03/15/99
Operation
On start-up the G-TRAC2 opens the dampers and starts the blower after a time delay. If there were a call for heat
the combustion blower would operate at full air to purge the heat exchanger. After the heat exchanger is purged,
the air and gas operators move to “light off position”. The G-TRAC2 closes contacts to activate a flame
supervision device. This device activates the ignition, supervises the pilot flame and main flame. After the main
flame is activated a “feedback” signal to G-TRAC2 terminal 3 allows the G-TRAC2 to modulate the heat as
required maintaining the discharge temperature set point. If there is an optional reset device attached, it
electronically modifies the discharge air set point. The “calculated set point” value can be read at the terminals
provided (See Section XVIII). The G-TRAC2 will modulate/cycle the burner as needed to maintain discharge air
temperatures.
Basic Features
1. Standard service and testing features such as status indicating LED’s, service pot, and temperature test
points.
2. Proportional and Integral (PI) discharge air temperature control.
3. Built in discharge set point with a 55 to 100ºF setting range (or optional remote set point).
4. Supports one of the optional resets (discharge set point reset) from the following list:
• Room
• Ambient
• 0-10 VDC
• 2-10 VDC
• 4-20 ma
5. Built in auto bypass low limit (can be switched off, Section X).
6. Alarm output contacts (LK). The contacts provide low limit and flame failure annunciation. (Note the Low Limit
bypass can be switched off, Section X.)
7. Has input terminals for the fan switch, heat switch, and time clock contact, usually remote controlled by a
remote panel, DDC controls etc. Other input terminals are internally controlled. (E.g. AS, 3, Feedback pots).
8. Intermittent night blower (and optional damper) operation. Unit discharges at an adjustable elevated
discharge temperature whenever the room calls. G-TRAC-2 has no night setback set point; therefore, a
second night stat is required for a lower set point.
9. Compatible with 0
10 VDC direct control signal. (E.g. CTRAC 2.1 or UNT Metasys). Optical isolation on the
digital and BMS inputs (+ and -).
V. WIRING
Power supply = 24 VAC @ 0.9 amps.
The G-TRAC2 terminals "T1 and T2" require a separate 24 VAC, 20 VA class 2 ungrounded isolation transformer
supplying power to only "T1 and T2".
Terminal “N” should be wired to the neutral which is common to the same grounded power source supplying
power to terminals (“HS, FS, K, AS, and 3”). All remote wiring less than 50 feet long installed in clean electrical
environments and attached to terminals “M, P, Q, U, X, Y, V, Z” and “OR” should be a minimum of 22 ga twisted
pair wire. For longer runs and electrically noisy installations, the use of a minimum 20 gauge-shielded wire is
recommended. (Shield to be grounded at G-TRAC-2 end only.)
The main digital outputs (damper, supply blower, combustion blower, flame relay, pilot valve, and lockout alarm)
are rated at 4 amps. Digital outputs “CA, CG, OA and OG” are rated at 1 amp at 24 VAC.
(30 paginas)
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