Manual 2100-537
I
Page 33 of 54
DESUPERHEATER
OPERATION OF THE HEAT RECOVERY
UNIT
The pump module is a very simple device containing basic
controls and a circulating pump. Heat is transferred from
the hot refrigerant (discharge gas) to the cool water.
The operation of the Desuperheater Pump Module is
controlled rst by the operation of the Geothermal Heat
Pump and secondly by internal controls within the Pump
Module. A low voltage signal from Thermostat “Y” is
connected to the desuperheater control board and acts as the
primary on/off switch for the circulating pump.
Also connected to this board is a temperature overlimit
device which shuts down the desuperheater once inlet
water has exceeded 125° so the water cannot create a scald
condition.
There are also two (2) thermistor sensors connected to
the control board. These thermistors are measuring and
controlling to ensure there is a positive heat differential
across the water being circulated. When operating in Part
Load Condition, there are certain conditions (Ground Loop
Temperatures versus Hot Water Temperatures) that potential
exists where heat could transfer from the hot water into
the refrigeration system instead of the refrigeration system
into the hot water. Through the control board logic, these
thermistors ensure there is at least 2° positive differential
between entering/leaving water temperatures and will shut
down the pump accordingly.
START UP AND CHECK OUT
Be sure all shut off valves are open and all power supplies
are on. Open a hot water faucet to permit any air to bleed
from the plumbing.
NOTE: The inherent design of this pump for maximum
efciency means this pump is not self-priming. It is
imperative to check that the air has been adequately bled
from the system. There is a bleed-port built into the pump
module that can be utilized after the system water has been
fully restored. The bleed port is located directly above the
pump in the GTC compressor unit.
Turn ON the air conditioning system and verify the
circulating pump will operate. Feel the “Water to Unit” and
“Water from Water Heater” tubes for noticeable difference
in temperature. Turn OFF the system and verify that the
circulating pump stops.
NOTE: When checking the refrigerant operating pressures
of the ground source heat pump. The desuperheater
must be turned off. With the desuperheater operating a
wide variance in pressures can result, giving the service
technician the indication there is a charge problem when the
unit is operating correctly.
MAINTENANCE
CLEANING THE HEAT EXCHANGER – If scaling of
the coil is strongly suspected, the coil can be cleaned with
a solution of phosphoric acid (food grade acid). Follow the
manufacturer’s directions for the proper mixing and use of
cleaning agent.
