Carrier 50YFV Installation, Operation And Maintenance Instructions page 22

R e s i d e n t i a l D i g i t a l P a c k a g e d U n i t s G T- P B S e r i e s - 6 0 H z P u r o n
R e v : 4 A p r i l , 1 4
Open Loop or Ground-Water Applications
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.
22
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.
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