19
ELECTRICAL - LOW VOLTAGE WIRING
Accessory Connections
A terminal paralleling the compressor contactor coil
has been provided on the CXM control. Terminal “A” is
designed to control accessory devices, such as water
valves. Note: This terminal should be used only with 24
Volt signals and not line voltage. Terminal “A” is energized
with the compressor contactor. See Figure 21 or the
specific unit wiring diagram for details.
Figure 21: Accessory Wiring
Water Solenoid Valves
An external solenoid valve may be used on some
installations to shut off flow to the unit when the
compressor is not operating. A slow closing valve may be
required to help reduce water hammer. Figure 21 shows
typical wiring for a 24VAC external solenoid valve. Figures
22 and 23 illustrate typical slow closing water control valve
wiring. Slow closing valves take approximately 60 seconds
to open (very little water will flow before 45 seconds).
Once fully open, an end switch allows the compressor
to be energized. Only relay or triac based electronic
thermostats should be used with slow closing valves.
When wired as shown, the slow closing valve will operate
properly with the following notations:
1. The valve will remain open during a unit lockout.
2. The valve will draw approximately 25-35 VA through
the “Y” signal of the thermostat.
Note: This valve can overheat the anticipator of an
electromechanical thermostat. Therefore, only relay or
triac based thermostats should be used.
Figure 22: Slow Closing Valve Wiring (Typical)
C
C
Termostato
Y
1
2
3
Y
AVM
Taco Válvula
Calentador Interruptor
Unidad Empacada
C
C
Thermostat
Y1
1
2
3
Y1
Valve
Heater Switch
Figure 23: Taco ESP Valve Wiring
Low Voltage VA Ratings
Component VA
Typical Blower Relay 6 - 7
Typical Reversing Valve Solenoid 4 - 6
30A Compressor Contactor 6 - 9
Subtotal 16 - 22
+ CXM board (5 - 9 VA)* 21 - 31
Remaing VA for Accessories 19 - 29
*Standard transformer for CXM board is 50VA.
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