Design Guide
HEV-HEH SEriES
Heat Controller
8
8
Engineering Design Guide
HEV/H SERIES
Heat Controller, LLC
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 40°F [4.4*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, as long as the EWT does not fall below 50°F, the system will operate as designed. For EWTs below 50°F, higher
ow rates will be required (open loop systems, for example, require at least 2 gpm/ton when EWT is below 50°F).
Heating - EAT 70°F
HWG
HC
KW
HE
LAT
COP HWG
Operation Not Recommended
11.2
1.2
7.3
85.3
2.8
1.6
0.7
12.5
1.2
8.5
87.3
3.1
1.7
0.7
13.0
1.2
9.0
88.1
3.2
1.7
0.7
13.3
1.2
9.3
88.5
3.3
1.7
0.8
14.5
1.2
10.4
90.3
3.6
1.8
0.7
15.2
1.2
11.1
91.3
3.7
1.8
0.7
15.5
1.2
11.4
91.9
3.8
1.8
1.1
16.5
1.2
12.4
93.4
4.0
1.9
0.9
17.3
1.2
13.2
94.6
4.2
2.0
0.8
17.7
1.2
13.6
95.3
4.3
2.0
1.5
18.5
1.2
14.4
96.5
4.5
2.0
1.2
19.4
1.2
15.2
97.9
4.7
2.1
1.1
19.9
1.2
15.7
98.6
4.8
2.2
2.1
20.5
1.2
16.3
99.5
4.9
2.2
