Installation Manual

SELECT AND WIRE THE TRANSFORMER TO THE CONTROL PANEL
1. Two separate 24-volt transformers are required for the
system. The HVAC Equipment transformer cannot be used
for power. Transformer #1 is used to power the zone panel
and thermostats. Transformer #2 is used to power the zone
dampers.
2. Wire 24VAC from Transformer #1 to the POWER, R & C
terminals (see FIGURE 7). Use a 20VA transformer for
Transformer #1.
3. Wire 24VAC from Transformer #2 to the DAMPER POWER,
R & C terminals (see FIGURE 8).
4. Sizing Transformer #2:
a. Select your damper type.
OPTION 1: Normally Open/Power Close Dampers
(2-Wire)
i. Add up all the zone dampers that are in the system.
ii. Subtract the number of dampers in the zone with
the least number of dampers. This is the greatest
number of dampers that could be energized at one
time.
iii. Multiply this number by 10 to determine the damper VA requirement.
Example: If you have a 4-zone system, and there are two dampers per zone, then the total number of dampers that could be energized at
one time is,
8 - 2 = 6 dampers
6 dampers x 10VA per damper = 60VA required
OPTION 2: Power Open/Power Close Dampers (3-Wire)
i. Add up all the zone dampers that are in the system.
ii. Multiply this number by 2.5 to determine the transformer size.
Example: If you have a 4-zone system, and there are two dampers per zone, then the total number of dampers that could be energized at
one time is,
8 dampers x 2.5VA per damper = 20VA required
b. Select a transformer that meets or exceeds the value calculated.
TRANSFORMER #1
DEDICATED
24 VAC
120 VAC
24 VAC
120 VAC
TRANSFORMER #2
DEDICATED
90-2092
90-2093
FIGURE 7 – TRANSFORMER #1
FIGURE 8 – TRANSFORMER #2
English 7