leaving loop temperature would be 25 to 22°F [-4 to -6°C]
and low temperature protection should be at 15°F [-10°C].
Calculation is as follows:
30°F - 15°F = 15°F [-1°C - 9°C = -10°C].
All alcohols should be premixed and pumped from a
reservoir outside of the building when possible or introduced
under the water level to prevent fumes. Calculate the total
volume of fluid in the piping system using Table 1. Then use
the percentage by volume shown in Table 2 for the amount
of antifreeze needed. Antifreeze concentration should be
checked from a well mixed sample using a hydrometer to
measure specific gravity.
Low Water Temperature Cutout Setting - CXM Control
When antifreeze is selected, the FP1 jumper (JW3) should
be clipped to select the low temperature (antifreeze 10°F
[-12.2°C]) set point and avoid nuisance faults (see “Low Water
Temperature Cutout Selection” in this manual).
Table 2: Antifreeze Percentages by Volume
Table 1: Approximate Fluid Volume (gal.) per 100' of Pipe
Type
Minimum Temperature for Low Temperature Protection
10°F [-12.2°C]
15°F [-9.4°C]
20°F [-6.7°C]
25°F [-3.9°C]
Methanol
100% USP food grade Propylene Glycol
Ethanol*
25%
38%
29%
21%
25%
25%
16%
22%
20%
10%
15%
14%
* Must not be denatured with any petroleum based product
Fluid Volume (gal [liters] per 100’ [30 meters) Pipe)
Pipe
Size
Volume (gal) [liters]
Copper
1”
4.1 [15.3]
1.25”
6.4 [23.8]
2.5”
9.2 [34.3]
Rubber Hose
1”
3.9 [14.6]
Polyethylene
3/4” IPS SDR11
2.8 [10.4]
1” iPS SDR11
4.5 [16.7]
1.25” IPS SDR11
8.0 [29.8]
1.5” IPS SDR11
10.9 [40.7]
2” IPS SDR11
18.0 [67.0]
1.25” IPS SCH40
8.3 [30.9]
1.5” IPS SCH40
10.9 [40.7]
2” IPS SCH40
17.0 [63.4]
Unit Heat Exchanger
Typical
1.0 [3.8]
Flush Cart Tank
10” Dia x 3ft tall
[254mm x 91.4cm tall]
10 [37.9]
Ground-Loop Heat Pump Applications
Figure 1: Typical Ground-Loop Application
Air Pad or
Extruded
polystyrene
insulation board
Unit Power
Disconnect
Thermostat Wiring
Wa t e r- t o - Wa t e r ( 5 0 Y E R ) S e r i e s - P u r o n
®
R e v. : 1 J u l y, 2 0 1 0
10
