Install Instructions

IOM - HZH/HZV Series
21
Ground-Water Heat Pump Applications
Flow Regulation - Units without vFlow™ - Flow
regulation can be accomplished by two methods. One
method of flow regulation involves simply adjusting the ball
valve or water control valve on the discharge line. Measure
the pressure drop through the unit heat exchanger, and
determine flow rate from Table 10. Since the pressure is
constantly varying, two pressure gauges may be needed.
Adjust the valve until the desired flow of 1.5 to 2 gpm per
ton [2.0 to 2.6 l/m per kW] is achieved. A second method
of flow control requires a flow control device mounted
on the outlet of the water control valve. The device is
typically a brass fitting with an orifice of rubber or plastic
material that is designed to allow a specified flow rate. On
occasion, flow control devices may produce velocity noise
that can be reduced by applying some back pressure from
the ball valve located on the discharge line. Slightly closing
the valve will spread the pressure drop over both devices,
lessening the velocity noise.
Note: When EWT is below 50°F [10°C], 2 gpm per ton
(2.6 l/m per kW) is required.
Water Coil Low Temperature Limit Setting - For all
open loop systems the 30°F [-1.1°C] LT1 setting (factory
setting-water) should be used to avoid freeze damage to
the unit. See “Low Water Temperature Cutout Selection” in
this manual for details on the low limit setting.