Specifications

19
The Smart Choice for Energy Efficiency
Th
he Smart Choice for Energ
Performance Data
Selection Notes
For operation in the shaded area when water is used
in lieu of an anti-freeze solution, the LWT (Leaving
Water Temperature) must be calculated. Flow must be
maintained to a level such that the LWT is maintained
above 42°F [5.6°C] when the JW3 jumper is not clipped
(see example below). This is due to the potential of the
refrigerant temperature being as low as 32°F [0°C] with
40°F [4.4°C] LWT, which may lead to a nuisance cutout
due to the activation of the Low Temperature Protection.
JW3 should never be clipped for standard range
equipment or systems without antifreeze.
Example:
At 50°F EWT (Entering Water Temperature) and 1.5 gpm/
ton, a 3 ton unit has a HE of 22,500 Btuh. To calculate
LWT, rearrange the formula for HE as follows:
HE = TD x GPM x 500, where HE = Heat of Extraction
(Btuh); TD = temperature difference (EWT - LWT) and
GPM = U.S. Gallons per Minute.
TD = HE / (GPM x 500)
TD = 22,500 / (4.5 x 500)
TD = 10°F
LWT = EWT - TD
LWT = 50 - 10 = 40°F
In this example, a higher fl ow rate will be required for EWTs at or below 50°F without antifreeze. At 2 gpm/ton, the
calculation above results in a TD of 7.5. LWT = 50 - 7.5 = 42.5°F, which is above 42°F EWT, and is acceptable for
this application.
7°F Heating - EAT 70°F
HR EER HC kW HE LAT COP
ended
5.5 0.50 3.8 91.0 3.22
10.9 26.7 6.0 0.51 4.3 93.1 3.44
10.9 29.9 6.3 0.52 4.5 94.1 3.55
10.9 31.7 6.4 0.52 4.7 94.8 3.62
10.8 22.9 6.9 0.53 5.1 96.5 3.79
10.9 25.8 7.2 0.54 5.4 97.9 3.91
10.9 27.4 7.4 0.55 5.6 98.6 3.97
10.6 19.6 7.8 0.56 5.9 100.0 4.10
10.8 22.1 8.2 0.57 6.3 101.6 4.23
10.8 23.4 8.4 0.57 6.5 102.4 4.30
10.4 16.6 8.7 0.58 6.7 103.6 4.39
105 188 92 059 72 1054 453