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3. Operate each heat pump in the heating cycle imme-
diately after checking cooling cycle operation. A time
delay will prevent the compressor from restarting for
approximately 5 minutes.
Note: Rooftop heat pump units are designed to start heating
at a minimum return air temperature of 40° F with normal
water flow rate and ambient temperature.
a.
If the unit has a MCO thermostat, set the
temperature indicator to the highest setting
and set the selector switch to HEAT. The
fan and the compressor should start. If the
unit has an optional ACO thermostat, set the
temperature indicator to the highest setting and
set the selector switch to AUTO. The fan and the
compressor should start.
b. Once the unit has begun to run, check for warm
air delivery at the unit grille. List the serial number
of any machines that do not function.
4. Establish a permanent operating record by logging
the unit operating conditions at initial start-up for
each unit.
Table 6: Operating Temperatures and Pressures
Water
Entering
Suction
Flow
charge
Water
Pressure
GPM/
Pressure
Temp °F
PSIG
ton
1.5
20
2.25
3
1.5
123-133
176-206
30*
2.25
111-131
164-184
3
107-127
156-176
1.5
129-139
225-255
50
2.25
128-138
213-233
3
126-136
203-223
1.5
135-145
300-330
70
2.25
135-145
281-301
3
134-144
269-289
1.5
140-150
386-426
90
2.25
139-149
366-396
3
138-148
358-378
1.5
138-158
428-478
100
2.25
137-157
409-449
3
141-151
397-437
1.5
144-164
544-574
120
2.25
143-163
511-571
3
142-162
495-555
*Based on 15% Methanol antifreeze solution
T H E S M A R T S O L U T I O N F O R E N E R G Y E F F I C I E N C Y
Cooling
Dis-
Sub-
Superheat
cooling
PSIG
19-29
19-29
25-35
18-28
29-39
17-27
10-20
13-23
15-25
12-22
18-28
12-22
5-15
12-22
6-16
10-20
7-17
8-18
3-13
13-23
4-14
10-20
4-14
8-18
3-13
13-23
3-13
10-20
4-14
8-18
2-12
11-21
3-13
10-20
3-13
8-18
I n s t a l l a t i o n , O p e r a t i o n , M a i n t e n a n c e
5. If a unit fails to operate, conduct the following checks:
a.
Check the voltage and current. They should
comply with the electrical specifications described
on the unit nameplate.
b. Look for wiring errors. Check for loose terminal
screws where wire connections have been made
on both the line and low-voltage terminal boards.
c.
Check for dirty filters. A clogged filter will cause
safety cutouts to stop unit operation.
d. Check the supply and return piping. They must
be properly connected to the inlet and outlet
connections on the unit.
e.
Check the fan. If the fan fails to operate, verify
that the fan wheel turns freely and that it is
secured to the shaft. Also verify that the fan
operates in both heating and cooling modes.
f.
If the checks described above fail to reveal the
problem and the unit still will not operate, contact
a trained service technician to ensure proper
diagnosis and repair of the equipment.
Water
Air Temp
Suction
Temp
charge
Drop °F
Pressure
Rise
Pressure
DB
PSIG
°F
56-66
280-320
21-25
20-22
62-72
291-321
14-16
18-22
67-77
291-331
10-12
16-22
69-79
294-334
20-24
19-25
93-103
320-360
12-16
19-23
99-109
325-365
10-12
19-23
103-113
329-369
19-23
19-21
125-135
247-397
12-16
18-22
135-145
362-402
8-14
17-23
139-149
361-411
17-23
17-21
160-170
382-432
11-15
17-21
164-184
388-448
9-11
17-21
170-190
395-455
16-22
16-20
11-15
17-21
9-11
17-21
15-21
11-15
10-14
15-19
7-11
14-20
R e v . : A u g u s t 1 9 , 2 0 2 0
Unit Start-Up
Heating
Dis-
Sub-
Superheat
cooling
PSIG
6-16
3-9
6-16
4-10
6-16
4-10
6-16
4-10
5-15
6-12
6-16
6-12
6-16
6-12
6-16
6-12
6-16
5-11
7-17
5-11
8-18
5-11
11-21
5-11
12-22
5-11
JRE - Series
Water
Air Temp
Temp
Rise °F
Drop
DB
°F
3-5
17-21
7-9
18-22
5-7
20-22
4-6
21-23
10-12
25-27
7-9
26-28
5-7
27-29
14-16
31-33
10-12
33-35
7-9
33-35
17-19
36-40
11-15
39-41
9-11
38-42
39
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