R e s i d e n t i a l D i g i t a l H & V - Tr a n q u i l i t y
®
2 2 D i g i t a l ( T Z ) S e r i e s - 6 0 H z H F C - 4 1 0 A
C r e a t e d : 2 6 O c t . , 2 0 1 1 B
24
G e o t h e r m a l H e a t P u m p S y s t e m s
Ground-Water Heat Pump Applications
recharge well, storm sewer, drain
fi
eld, adjacent stream
or pond, etc.). Most local codes forbid the use of sanitary
sewer for disposal. Consult your local building and zoning
department to assure compliance in your area.
The pump should be sized to handle the home’s domestic
water load (typically 5-9 gpm [23-41 l/m]) plus the
fl
ow rate
required for the heat pump. Pump sizing and expansion
tank must be chosen as complimentary items. For example,
an expansion tank that is too small can cause premature
pump failure due to short cycling. Variable speed pumping
applications should be considered for the inherent energy
savings and smaller pressure tank requirements.
Internal Motorized Modulating Valve
TZ series units are available with an internal motorized
modulating water valve for open loop applications. The
internal motorized modulating valve replaces the water control
valve and
fl
ow regulator used in earlier non Plug and Play
units. The valve (ball valve) regulates the
fl
ow using
∆
T of the
system. Pressure drop through the unit heat exchanger can
be measured using two pressure gauges on the unit’s two
pressure ports. Entering and leaving water temperature is read
on the communicating thermostat / con
fi
guration tool.
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.
