![Johnson Controls JRE Series Installation Operation & Maintenance Download Page 39](http://html1.mh-extra.com/html/johnson-controls/jre-series/jre-series_installation-operation-and-maintenance_2024185039.webp)
JRE-Series
R e v. : A u g u s t 1 9 , 2 0 2 0
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
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
39
Unit Start-Up
Cooling
Heating
Entering
Water
Temp °F
Water
Flow
GPM/
ton
Suction
Pressure
PSIG
Dis-
charge
Pressure
PSIG
Superheat
Sub-
cooling
Water
Temp
Rise
°F
Air Temp
Drop °F
DB
Suction
Pressure
PSIG
Dis-
charge
Pressure
PSIG
Superheat
Sub-
cooling
Water
Temp
Drop
°F
Air Temp
Rise °F
DB
20
1.5
2.25
3
56-66
280-320
6-16
3-9
3-5
17-21
30*
1.5
2.25
3
123-133
111-131
107-127
176-206
164-184
156-176
19-29
25-35
29-39
19-29
18-28
17-27
21-25
14-16
10-12
20-22
18-22
16-22
62-72
67-77
69-79
291-321
291-331
294-334
6-16
6-16
6-16
4-10
4-10
4-10
7-9
5-7
4-6
18-22
20-22
21-23
50
1.5
2.25
3
129-139
128-138
126-136
225-255
213-233
203-223
10-20
15-25
18-28
13-23
12-22
12-22
20-24
12-16
10-12
19-25
19-23
19-23
93-103
99-109
103-113
320-360
325-365
329-369
5-15
6-16
6-16
6-12
6-12
6-12
10-12
7-9
5-7
25-27
26-28
27-29
70
1.5
2.25
3
135-145
135-145
134-144
300-330
281-301
269-289
5-15
6-16
7-17
12-22
10-20
8-18
19-23
12-16
8-14
19-21
18-22
17-23
125-135
135-145
139-149
247-397
362-402
361-411
6-16
6-16
7-17
6-12
5-11
5-11
14-16
10-12
7-9
31-33
33-35
33-35
90
1.5
2.25
3
140-150
139-149
138-148
386-426
366-396
358-378
3-13
4-14
4-14
13-23
10-20
8-18
17-23
11-15
9-11
17-21
17-21
17-21
160-170
164-184
170-190
382-432
388-448
395-455
8-18
11-21
12-22
5-11
5-11
5-11
17-19
11-15
9-11
36-40
39-41
38-42
100
1.5
2.25
3
138-158
137-157
141-151
428-478
409-449
397-437
3-13
3-13
4-14
13-23
10-20
8-18
16-22
11-15
9-11
16-20
17-21
17-21
120
1.5
2.25
3
144-164
143-163
142-162
544-574
511-571
495-555
2-12
3-13
3-13
11-21
10-20
8-18
15-21
10-14
7-11
11-15
15-19
14-20
*Based on 15% Methanol antifreeze solution
Table 6: Operating Temperatures and Pressures
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.
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.