15
GEO16-501.4
START-UP PROCEDURE
9. If temperature drop is outside of expected operating range,
check refrigerant pressures and compare to those shown in
Table 16.1.
10. Check air temperature rise across the coil. Air temperature
rise should be between 20°F and 30°F.
11. Check for vibration, noise and leaks.
12. Lower thermostat set point below room temperature and
verify that compressor and flow center deactivate.
13. Initiate a control signal to place the unit in the cooling mode.
Cooling set point must be set below room temperature.
14. Cooling will energize after a time delay.
15. Be sure that the compressor and flow center are activated.
16. Monitor ground water supply (GWI) and return (GWO)
temperatures. If temperature rise is within expected
operating range as shown in Table 16.1, continue with
testing.
17. If temperature drop is outside of expected operating range,
check refrigerant pressures and compare to those shown in
Table 16.1.
18. Check for an air temperature drop of 15°F to 25°F across
the air coil.
19. Check for vibration, noise and leaks.
20. Adjust the cooling set point above the room temperature and
verify that the compressor and flow center deactivate.
21. If unit fails to operate as described, see troubleshooting
section. If the unit still does not operate properly, contact
Modine at the number listed on the back of this manual.
22. When testing is complete, set system to normal operating
mode.
DHW Startup Procedure
1. If the DHW was wired, the DHW pump will run whenever the
heat pump is running and the DHW Supply temperature is
below 120°F and the discharge temperature is above 100°F.
2. To verify operation of the DHW pump, ensure that the heat
pump is running and the DHW temperature is below 120°F
and the discharge temperature is above 100°F.
3. The temperature rise across the desuperheater should be
5-10°F.
Sequence of Operation
The unit’s controller will monitor calls for heat or cooling by
thermostat(s).
Blower:
The blower will cycle with a call for cooling or heating.
Cool:
Upon receiving a a G, Y1, and O signal from the
thermostat, the blower, compressor and reversing valve will be
energized. On two stage units with ECM, the first stage of the
compressor will be energized and the blower will provide the
first stage airflow. The compressor will be limited by a timer
that will provide anti-cycle protection. When a subsequent Y2
signal is received, the second stage of the compressor will be
energized and the blower will provide second stage airflow (two
stage units with ECM only).
Heat:
Upon receiving a G and Y1 and signal from the
thermostat, the blower and compressor will be energized. On
two stage units with ECM, the first stage of the compressor will
be energized and the blower will provide the first stage airflow.
The compressor will be limited by a timer that will provide anti-
cycle protection. When a subsequent Y2 signal is received,
the second stage of the compressor will be energized and the
blower will provide second stage airflow (two stage units with
ECM only).
Open Loop Systems:
An optional valve can be fitted to stop
water flow when the compressor is not energized. This allows
the pumping system to work more efficiently.
Supplemental Electric Heat (Field Installed Accessory):
Upon receiving a W1 signal from the thermostat, heat is
energized. Upon receiving a W2/E signal from the thermostat,
electric heat is energized.
Table 15.1 - Water Pressure Drop, psi
(Based on Entering Water Temperature)
Models
GPM
30°F
40°F
60°F
90°F
110°F
024
4.0
0.8
0.8
0.7
0.6
0.6
5.0
1.1
1.1
0.9
0.8
0.8
6.0
1.4
1.4
1.2
1.1
1.0
7.0
1.8
1.8
1.5
1.4
1.3
8.0
2.2
2.1
1.9
1.7
1.6
036
6.0
1.9
1.8
1.6
1.4
1.3
8.0
2.9
2.8
2.5
2.1
2.0
9.0
3.5
3.4
3.0
2.6
2.4
10.0
4.1
4.0
3.5
3.0
2.8
12.0
5.5
5.4
4.7
4.1
3.7
048
6.0
0.6
0.6
0.5
0.5
0.4
8.0
0.9
0.9
0.8
0.7
0.7
10.0
1.3
1.3
1.1
1.0
1.0
12.0
1.7
1.7
1.5
1.4
1.3
14.0
2.2
2.2
2.0
1.8
1.7
060
&
072
9.0
1.1
1.2
1.0
0.9
1.0
12.0
1.8
1.9
1.7
1.5
1.6
15.0
2.7
2.7
2.5
2.2
2.3
18.0
3.8
3.7
3.4
3.1
3.0
21.0
5.0
4.9
4.5
4.1
3.9
24.0
6.3
6.2
5.8
5.3
4.9
Equation 15.1 - Coaxial Coil Pressure Drop
Antifreeze Correction
To find actual pressure drop through either coaxial coil
when the unit is operated with an antifreeze solution, rather
than water:
Where:
WPD
A
= Water Pressure Drop at Actual Conditions
WPD
S
= Water Pressure Drop at Standard Conditions
(water) from Table 18.1
ACF
= Antifreeze Correction Factor from Table 18.2
WPD
A
=
WPD
S
x ACF
Table 15.2 - Antifreeze Pressure Drop Corrections
Antifreeze Type
Antifreeze Solution
Percent by Weight
Correction Factor
Ethylene Glycol
15%
1.12
20%
1.16
30%
1.22
Propylene Glycol
15%
1.20
20%
1.27
30%
1.43
38%
1.55
Ethanol
14%
1.29
20%
1.34
29%
1.43
Methanol
10%
1.12
15%
1.16
20%
1.19
25%
1.21
