Operating instructions

6
Figure 2 – Open Loop Water Plumbing
The heat pump should never be operated with flow rates
less than specified. Low flow rates or no flow may result
in freezing water in the water to refrigerant heat
exchanger. This will cause the unit to shut down on low-
pressure lockout. If the unit locks out, verify that the unit
has the required flow and reset the unit by shutting off
power to the unit for one minute. II DO NOT continually
reset the unit, if the unit locks out more than once call
your service professional. (( Continued reset of the unit
can freeze water inside the water coil to the point of
rupturing the water coil.
1. Open Loop Freeze Protection Switch
Heat pump installations on open loop systems, using a
non-antifreeze protected water source during the heating
mode, require the use of a freeze protection switch. If the
water supply to the heat pump is interrupted for any
reason, continued operation of the compressor would
cause the water remaining in the water-to-refrigerant heat
exc hanger to freeze and rupture the copper inner tube.
The freeze protection switch (ECONAR Part # 75-1028)
will shut the unit down before freezing can occur and
protect the heat pump against loss of flow. A freeze
protection switch must be field installed on open loop
GeoSource 2000 heat pumps before the warranty can be
registered on the heat pump. The switch mounts on the
compressor’s suction line and is wired to terminals on the
controller (from X to FP). After the freeze protection
switch is installed, the J4 jumper must be removed from
the controller to activate the switch. The low pressure
switch now locks the unit off at 35 psi pressure in the
heating mode.
2. Water Coil Maintenance
Water quality is a major concern for open systems.
Problems can occur from scaling, particle buildup,
suspended solids, corrosion, pH levels outside the 7-9
range, or biological growth. If poor water quality is
known to exist in your area, a cupro-nickel water coil may
be required when ordering the system, or installing a
closed loop system may be the best alternative. Water
coil cleaning on open loop systems may be necessary on a
regular basis. Depending on the specific water quality
issue, the water coil can be cleaned by the following
methods:
a. Freeze Cleaning (Scale deposits, particle
buildup)
I. Before using the freeze cleaning procedure, verify that
it needs to be done. Answer the following questions to
determine if servicing is required.
1. Determine and verify that the required water flow
rate in GPM is both present and correct.
2. Determine the temperature differential of the
water. Under normal conditions, there should be a
temperature difference of about 10-15 degrees
between the supply side and discharge side. If the
temperature difference is 8 degrees or less,
consideration should then be given to cleaning the
water coil heat exchanger.
II. If cleaning of the water coil is indicated, please
carefully follow the steps listed below to utilize the freeze
cleaning method.