24
G e o t h e r m a l H e a t i n g a n d Co o l i n g
Tranquility
®
30 Digital (TE) Series IOM - 60Hz HFC-410A
R e v. : O c t o b e r 5 , 2 0 2 1
Open Loop or Ground-Water Heat Pump Applications
Pressure Tank and Pump
Use a closed, bladder-type pressure tank to minimize
mineral formation due to air exposure. The pressure tank
should be sized to provide at least one minute continuous
run time of the pump using its drawdown capacity rating to
prevent pump short cycling. Discharge water from the unit
is not contaminated in any manner and can be disposed
of in various ways, depending on local building codes (e.g.
recharge well, storm sewer, drain field, 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 flow 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.
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” (Figure 17) in this manual for details on the low
limit setting.
