Scroll Compressor Rotation; Unit Start-Up Cooling Mode - Carrier AQUAZONE PCV015-060 Installation And Service Instructions Manual

Table 14 — Operating Limits — 50PCH,PCV Units
AIR LIMITS
Min. Ambient Air – db
Rated Ambient Air – db
Max. Ambient Air – db
Min. Entering Air – db/wb
Rated Entering Air – db/wb
Max. Entering Air – db/wb
WATER LIMITS
Min. Entering Water
Normal Entering Water
Max. Entering Water
Normal Water Flow
LEGEND
db — Dry Bulb
wb — Wet Bulb
Scroll Compressor Rotation —
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.
Table 16 — 50PC015,018 Typical Unit Operating Pressures and Temperatures
ENTERING
WATER
WATER
Suction
FLOW
TEMP
Pressure
(GPM/ton)
(F)
(psig)
1.5 120-130
2.25 120-130
30
3 120-130
1.5 137-147
2.25 137-147
50
3 137-147
1.5 142-152
70 2.25 142-152
3 142-152
1.5 146-156
90 2.25 146-156
3 146-156
1.5 154-164
110 2.25 154-164
3 154-164
LEGEND
DB — Dry Bulb
— — No Heating Operation in This Temperature Range
50PCH,PCV
Cooling (F) Heating (F)
45 39
80.6 68
110 85
50 40
80.6/66.2 68
110/83 80
30 20
50-110 30-70
120 90
2.5-3.0 gpm per ton
It is important to
COOLING
Water
Discharge Super- Sub-
Temp
Pressure heat cooling
Rise
(psig) (F) (F)
155-175 27-32 11-16 16.9-19.9
142-162 27-32 9-14 12.5-14.5
128-148 27-32 9-14 8.1-10.1
220-240 16-21 10-15 17.0-19.0
206-226 16-21 8-13 12.6-14.6
192-212 16-21 8-13 8.4-10.4
287-307 7-12 10-15 15.9-17.9
273-239 7-12 8-13 11.8-13.8
259-279 7-12 8-13 7.8- 9.8
375-395 6-11 10-15 14.9-16.9
361-381 6-11 8-13 11.0-13.0
347-367 6-11 8-13 7.2- 9.2
478-498 6-11 10-15 14.0-16.0
461-481 6-11 8-13 10.2-12.2
445-465 6-11 8-13 6.5- 8.5
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
WATER FLOW RATE (GPM)
For Closed Loop: Ground Source or
Cooling/Boiler Systems at 3 gpm/ton
For Open Loop: Ground Water Systems at
1.5 gpm/ton
Air Temp Suction Discharge
Drop Pressure Pressure
(F) DB (psig)
(F)
16-22 73- 83 268-288
17-23 75- 85 270-290
17-23 78- 88 272-292
16-22 102-112 295-315
17-23 106-116 297-317
17-23 110-120 299-319
16-22 131-141 324-344
17-23 137-147 326-346
17-23 144-154 328-348
16-22 174-184 360-380
17-23 180-190 367-387
17-23 187-197 374-394
16-22 —
16-22 —
16-22 —
28
COOLING
RISE (F)
Min Max
9 12
20 26
HEATING
Water
Super- Sub-
Temp
heat cooling
Drop
(psig) (F) (F)
(F)
8-13 4- 9 6.1- 8.1
8-13 4- 9 4.4- 6.4
8-13 4- 9 2.9- 4.9
8-13 8-13 9.1-11.1
8-13 8-13 6.9- 8.9
8-13 8-13 4.7- 6.7
9-14 10-15 12.1-14.1
9-14 10-15 9.3-11.3
9-14 10-15 6.6- 8.6
10-15 12-17 15.8-17.8
11-16 12-17 11.9-13.9
12-17 12-17 8.0-10.0
— — — —
— — — —
— — — —
HEATING
DROP (F)
Min Max
4 8
10 17
Air Temp
Rise
(F) DB
15-21
16-22
16-22
20-26
21-27
21-27
25-33
26-34
26-34
32-40
33-41
33-41
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—
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