Electrical - Low Voltage - Heat Controller HKV Installation, Operation & Mainenance Manual

Commercial vertical packaged heat pump: hkv large commercial

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Table Of Contents

Table of Contents

Heat Controller, Inc.

Low Water Temperature Cutout - FP1

The CXM control allows the field selection of source fluid low

temperature cutout points. The factory setting of FP1 is set for

water (30°F [-1.1°C]). In cold temperature applications jumper

JW3 (FP1- antifreeze 10°F [-12.2°C]) should be clipped as

shown in Figure 8 to change the setting to 10°F [-12.2°C], a more

suitable temperature when using antifreezes. It should be noted

that the extended range option should be specified to operate the

HB Series at entering water temperatures below 60°F [15°C].

Figure 8: FP1 Jumper

Accessory Connections

A terminal paralleling the compressor contactor coil has been

provided on the CXM control board. "A" has been provided to

control accessory devices, such as water valves, electronic

air cleaners, humidifiers, etc. Note: This terminal must be

used only with 24 Volt signals and not line voltage sig-

nals. This signal operates with the compressor contactor. See

Figure 9 or the wiring schematic for details.

Water Solenoid Valves

When using external solenoid valves on ground water

installations, a slow closing valve may be desired. Figure 9

illustrates a typical slow closing water control valve wiring

which will limit wasted water during a lockout condition. A slow

HKV LArge CommerCiAL

Figure 9: 24 Volt Accessory Wiring

CXM Terminal Strip

closing valve may be required to prevent water hammer.

When using an AVM -Taco Slow Closing valve on HKV

Series equipment Figure 10 wiring should be utilized. The

valve takes approximately 60 seconds to open (very little

water will flow before 45 seconds) and it activates the

compressor only after the valve is completely opened (by

closing its end switch). Only relay or triac based electronic

thermostats should be used with the AVM valve. When

wired as shown, the 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 can overheat the

anticipators of electromechanical thermostats. Therefore

only relay or triac based thermostats should be used.

Figure 10: Well Water AVM Valve Wiring

CAUTION! For units with manual or electric water shut-off

valve. DAMAGE WILL OCCUR if shut-off valve is closed

during unit operation. A high pressure switch must be installed

on the heat pump side of any field provided shut-off valves

and connected to the heat pump controls in series with the

built-in refrigerant circuit high pressure switch to disable

compressor operation if water pressure exceeds pressure

switch setting. The field installed high pressure switch shall

have a cut-out pressure of 300 psig and a cut-in pressure of

250 psig.