R e s i d e n t i a l H & V - 6 0 H z H F C - 4 1 0 A :
R e v : O c t o b e r 5 , 2 0 2 1
28
G e o t h e r m a l H e a t i n g a n d Co o l i n g
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 20 or the specific unit wiring diagram
for details.
Water Solenoid Valves
An external solenoid valve(s) should be used on ground
water 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 20 shows
typical wiring for a 24VAC external solenoid valve. Figures
21 and 22 illustrate typical slow closing water control valve
wiring for Taco 500 series (ClimateMaster P/N AVM…)
and Taco SBV series valves. 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.
Note: When EWT is below 50°F [10°C], a minimum of 2
gpm per ton (2.6 l/m per kW) is required.
Figure 20: Accessory Wiring
Figure 21: AVM Valve Wiring
C
C
Termostato
Y
1
2
3
Y
AVM
Taco Válvula
Calentador Interruptor
Unidad Empacada
C
C
Aquastat
Y1
1
2
3
Y1
AVM
Taco Valve
Heater Switch
DXM2
Thermostat
Figure 22: Taco SBV Valve Wiring
