MODGAS-XWR2 Technical Guide
OVERVIEW
3
General Information
Features
The MODGAS-XWR2 Controller provides the following:
•
Can control two (2) Gas Valves using input from
Proof of Ignition Modules
•
A second MODGAS-XWR2 Controller can be added as a
slave to allow control of 4 modulating gas valves.
•
Monitors Supply Air Temperature and Supply Air Reset
and modulates gas valves to maintain Setpoint
•
Provides active relays to control the Fan, Fan Speed, and
Heat Stages
•
Controls up to 4 stages of Heat with one Controller
•
Contains a 2 x 8 LCD character display and 4 buttons
that allow for status display, setpoint changes, and
configuration changes
NOTE:
The MODGAS-XWR2 Controller contains no user-
serviceable parts. Contact qualified technical personnel
if your MODGAS-XWR2 Controller is not operating
correctly.
Overview
The MODGAS-XWR2 Controller (previously referred to as the MOD-
GAS-XWR-1) is designed to be used with White-Rogers
®
valves only.
It will modulate up to two (2) White-Rogers
®
gas valves to maintain a
desired Discharge (Supply) Air Temperature (up to four (4) modulating
gas valves may be controlled when a second MODGAS-XWR2 Control-
ler configured as a slave module). The MODGAS-XWR2 Controller also
controls the speed of the induced draft fan to maintain proper combustion
in the heat exchanger. See
Figure 1
,
page 4
.
NOTE:
The MODGAS-XWR2 provides (2) more relays than the
MODGAS-XWR Controller. The MODGAS-XWR2 Controller can
replace the MODGAS-XWR Controller. See
page 36
for drop-in re-
placement instructions.
The controller can be used as a stand-alone unit or be connected to
a 12 Relay E-BUS Expansion Module (stand-alone only) or VCCX2
Controller, VCB-X Controller, or VCM-X E-BUS (I
2
C) Controller us-
ing a modular cable.
The MODGAS-XWR2 Controller can be configured for: one (1) modu
-
lating valve with one ignitor as one stage, two (2) modulating valves with
one ignitor as one stage, two (2) modulating valves with two ignitors as
one stage, and two (2) modulating valves, with two ignitors as two stages.
Two MODGAS-XWR2 Controllers (Primary/Secondary) may be con-
figured to control four (4) modulating valves as one stage - two valves
with one ignitor on each board. In addition, two Controllers may be
configured to control four (4) modulating valves with two ignitors on
each board. The first valve on each board is stage one and the second
valve on each board is stage two.
NOTE:
Primary/Secondary configu
-
ration is not supported using I
2
C communications (VCM-X E-BUS).
The MODGAS-XWR2 Controller can also control or effect control of ad
-
ditional fixed valves for additional stages of heat by using the additional
Heat Relays on the board itself. When the MODGAS-XWR2 is attached
to one of the listed Unit Controllers, these additional stages are affected
through the Unit Controller. In stand-alone mode, these additional fixed
heat stages can be increased by attaching a 12 Relay E-BUS Expansion
Module. And in communicating mode, additional fixed heat stages can
be increased by attaching a 12 Relay E-BUS Expansion Module to the
Unit Controller.
Содержание MODGAS-XWR2
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