Heat Controller HTS SERIES SPLIT SYSTEM, HSS manual Electrical - Low Voltage Wiring, Cxm Pcb

H E AT C O N T R O L L E R , I N C . WAT E R - S O U R C E H E AT P U M P S

R e s i d e n t i a l S p l i t - 6 0 H z R 2 2 & R 4 1 0 A

R e v. : 5 J u n e , 2 0 0 8

Electrical - Low Voltage Wiring

Figure 23: FP1 Limit Setting

	JW3-FP1 jumper
	should be clipped
CXM PCB	for low temperature
	operation

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 24 or the specific unit wiring diagram for details.

Figure 24: Accessory Wiring

Water Solenoid Valves - “Indoor” Compressor Section Only

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 24 shows typical wiring for a 24VAC external solenoid valve. Figures 25 and 26 illustrate typical slow closing water control valve wiring for Taco 500 series (HCI P/N AVM…) and Taco ESP 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.

Two-stage HTS Units

Two-stage units should be designed with two parallel valves for ground water applications to limit water use during first stage operation. For example, at 1.5 gpm/ton [2.0 l/m per kW], a model 049 unit requires 6 gpm [23 l/m] for full load (2nd stage) operation, but only 4 gpm [15 l/m] during 1st stage operation. Since the unit will operate on first stage

80-90% of the time, significant water savings can be realized by using two parallel solenoid valves with two flow regulators. In the example above, stage one solenoid would be installed with a 4 gpm [15 l/m] flow regulator on the outlet, while stage two would utilize a 2 gpm [8 l/m] flow regulator. When stage one is operating, the second solenoid valve will be closed. When stage two is operating, both valves will be open, allowing full load flow rate.

Figure 27 illustrates piping for two-stage solenoid valves. Review figures 24-26 for wiring of stage one valve. Stage two valve should be wired between “Y2” (compressor solenoid

--wire nut connection) and terminal “C.” 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 25: AMV Valve Wiring

C Y1

	2	AMV
1	Heater Switch	3 Taco Valve

C	Y1
	Thermostat

Figure 26: Taco SBV Valve Wiring

28 H e a t C o n t r o l l e r, I n c . Wa t e r - S o u r c e H e a t i n g a n d C o o l i n g S y s t e m s