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VCCX2 Controller Technical Guide
MODGAS-X Wiring
The ASM01668 MODGAS-X is designed to modulate up to two
gas valves to maintain a desired Discharge Air Temperature. It
also controls the speed of the induced draft fan to maintain proper
combustion in the heat exchanger. The MODGAS-X directly
connects to the VCCX2 Controller or indirectly using an E-BUS
Expansion Board via an E-BUS cable. See
Figure 42, this page
.
NOTE:
If using multiple E-BUS sensors or modules, a
E-BUS hub or adapter board may be required.
The following information will be passed between the
MODGAS-X and the VCCX2 Controller:
•
Heat activation command
•
Heating Discharge Setpoint
•
The offset for the Supply Air Temperature Sensor
•
High Limit Temperature Setpoint
•
If the communication is interrupted between the
MODGAS-X and the VCCX2 Controller, the
MODGAS-X will revert to stand-alone operation.
For more information, refer to the
MODGAS-X Technical Guide
.
Supply
Air Temperature
Sensor
Mount In Supply
Air Duct
Connect Supply Air Temperature
Sensor to AI3 & GND
on VCCX2 Controller
E-BUS cable
connects to
VCCX2 Controller’s
Expansion Port
Set Jumper to 1.
Fan Enable
Low Speed Fan
24 VAC power input terminals
maximum power consumption
One Gas Valve = 18 VA
Two Gas Valves = 33 VA
Aux Heat Valve
Note:
1. 24 VAC must be connected so
that all ground wires remain common.
2. All wiring to be in accordance with
local and national electrical codes
and specifications.
18-30 VAC
GND
Two gas valves can
be connected as
shown
Line
Voltage
40 VA
Transformer
minimum
Figure 42: MODGAS-X to VCCX2 Controller Wiring
WIRING
MODGAS-X