York T2GY, Installer'S Manual

Page: 13 / 46

13
T2GY INSTALLER’S GUIDE
Adequate rate of flow (GPM) is very important to
system performance and long term reliability. Follow the
guidelines for recommended flow and pipe sizing in the
Recommendations table.
The unit uses an external temperature sensor such as the
lower thermostat in a water heater storage tank to control
the tank temperature. The thermostat should be wired
to the unit P5 connector wires, P5-11 and P5-4 tan wires.
When the tank temperature drops below the thermostat
setting the contacts in the thermostat will close and initiate
a signal to the unit to heat water.
A storage tank must be used to store the heated water
supplied by the unit. It is not recommended to send heated
water from the unit directly to the hydronic zones since the
unit also has the ability to condition the space with forced
air. There must be adequate storage capacity in the storage
tank to accommodate the hydronic load while the unit is
operating in forced air mode. The hydronic storage tank
should be sized to provide 2 gallons of storage capacity for
every one thousand Btuh’s of nominal heat pump capacity.
Adequate rate of flow (GPM) is very important to system
performance and long term reliability. Follow the guidelines
for recommended flow and pipe sizing in the unit
recommendations table.
Be sure to burp the pump. Open the screw 2 turns only in
the end of the pump motor (if Grundfos
®
pumps are used)
to allow trapped air to be discharged and to ensure the
motor housing has been flooded.
The red “courtesy” wires exit out of the top of the Geo
Storage tank. The wires must be connected to the tank
thermostat and to P5 tan connector wires, P5-11 and P5-4
on the main logic board.
Hydronic Section cont.
Geothermal Storage Tank Thermostat
Thermostat
The unit must be wired to the thermostat screw terminals. The
yellow thermistor wires will not operate with the T2GY as they are
used with the T1GW water-to-water.