Scroll compressor rotation, Unit start-up cooling mode – Carrier AQUAZONE PCV015-060 User Manual
Page 28
28
Table 14 — Operating Limits — 50PCH,PCV Units
LEGEND
Scroll Compressor Rotation —
It is important to
be certain compressor is rotating in the proper direction. To
determine whether or not compressor is rotating in the prop-
er direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge
pressure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge
pressure does not rise to normal levels:
1. Turn off power to the unit. Install disconnect tag.
2. Reverse any two of the unit power leads.
3. Reapply power to the unit and verify pressures are correct.
The suction and discharge pressure levels should now move
to their normal start-up levels.
When the compressor is rotating in the wrong direction, the
unit makes more noise and does not provide cooling.
After a few minutes of reverse operation, the scroll com-
pressor internal overload protection will open, thus activating
the unit lockout. This requires a manual reset. To reset, turn the
thermostat on and then off.
NOTE: There is a 5-minute time delay before the compressor
will start.
Unit Start-Up Cooling Mode
1. Adjust the unit thermostat to the warmest position.
Slowly reduce the thermostat position until the compres-
sor activates.
2. Check for cool air delivery at unit grille a few minutes
after the unit has begun to operate.
3. Verify that the compressor is on and that the water flow
rate is correct by measuring pressure drop through the
heat exchanger using P/T plugs. See Table 15. Check the
elevation and cleanliness of the condensate lines; any
dripping could be a sign of a blocked line. Be sure the
condensate trap includes a water seal.
4. Check the temperature of both supply and discharge wa-
ter. Compare to Tables 16-22. If temperature is within
range, proceed. If temperature is outside the range, check
the cooling refrigerant pressures in Tables 16-22.
5. Check air temperature drop across the coil when com-
pressor is operating. Air temperature drop should be
between 15 and 25 F.
Table 15 — Water Temperature Change
Through Heat Exchanger
Table 16 — 50PC015,018 Typical Unit Operating Pressures and Temperatures
LEGEND
AIR LIMITS
50PCH,PCV
Cooling (F)
Heating (F)
Min. Ambient Air – db
45
39
Rated Ambient Air – db
80.6
68
Max. Ambient Air – db
110
85
Min. Entering Air – db/wb
50
40
Rated Entering Air – db/wb
80.6/66.2
68
Max. Entering Air – db/wb
110/83
80
WATER LIMITS
Min. Entering Water
30
20
Normal Entering Water
50-110
30-70
Max. Entering Water
120
90
Normal Water Flow
2.5-3.0 gpm per ton
db — Dry Bulb
wb — Wet Bulb
WATER FLOW RATE (GPM)
COOLING
RISE (F)
HEATING
DROP (F)
Min
Max
Min
Max
For Closed Loop: Ground Source or
Cooling/Boiler Systems at 3 gpm/ton
9
12
4
8
For Open Loop: Ground Water Systems at
1.5 gpm/ton
20
26
10
17
ENTERING
WATER
TEMP
(F)
WATER
FLOW
(GPM/ton)
COOLING
HEATING
Suction
Pressure
(psig)
Discharge
Pressure
(psig)
Super-
heat
(F)
Sub-
cooling
(F)
Water
Temp
Rise
(F)
Air Temp
Drop
(F) DB
Suction
Pressure
(psig)
Discharge
Pressure
(psig)
Super-
heat
(F)
Sub-
cooling
(F)
Water
Temp
Drop
(F)
Air Temp
Rise
(F) DB
30
1.5
120-130
155-175
27-32
11-16
16.9-19.9
16-22
73- 83
268-288
8-13
4- 9
6.1- 8.1
15-21
2.25
120-130
142-162
27-32
9-14
12.5-14.5
17-23
75- 85
270-290
8-13
4- 9
4.4- 6.4
16-22
3
120-130
128-148
27-32
9-14
8.1-10.1
17-23
78- 88
272-292
8-13
4- 9
2.9- 4.9
16-22
50
1.5
137-147
220-240
16-21
10-15
17.0-19.0
16-22
102-112
295-315
8-13
8-13
9.1-11.1
20-26
2.25
137-147
206-226
16-21
8-13
12.6-14.6
17-23
106-116
297-317
8-13
8-13
6.9- 8.9
21-27
3
137-147
192-212
16-21
8-13
8.4-10.4
17-23
110-120
299-319
8-13
8-13
4.7- 6.7
21-27
70
1.5
142-152
287-307
7-12
10-15
15.9-17.9
16-22
131-141
324-344
9-14
10-15
12.1-14.1
25-33
2.25
142-152
273-239
7-12
8-13
11.8-13.8
17-23
137-147
326-346
9-14
10-15
9.3-11.3
26-34
3
142-152
259-279
7-12
8-13
7.8- 9.8
17-23
144-154
328-348
9-14
10-15
6.6- 8.6
26-34
90
1.5
146-156
375-395
6-11
10-15
14.9-16.9
16-22
174-184
360-380
10-15
12-17
15.8-17.8
32-40
2.25
146-156
361-381
6-11
8-13
11.0-13.0
17-23
180-190
367-387
11-16
12-17
11.9-13.9
33-41
3
146-156
347-367
6-11
8-13
7.2- 9.2
17-23
187-197
374-394
12-17
12-17
8.0-10.0
33-41
110
1.5
154-164
478-498
6-11
10-15
14.0-16.0
16-22
—
—
—
—
—
—
2.25
154-164
461-481
6-11
8-13
10.2-12.2
16-22
—
—
—
—
—
—
3
154-164
445-465
6-11
8-13
6.5- 8.5
16-22
—
—
—
—
—
—
DB
— Dry Bulb
—
— No Heating Operation in This Temperature Range