Antifreeze - Carrier Aquazone 50PCH Series Installation, Start-Up And Service Instructions Manual

3. Maintain a fluid level in the tank above the return tee to avoid
air entering back into the fluid.
4. Shutting off the return valve that connects into the flush cart
reservoir will allow 345 kPa surges to help purge air pockets.
This maintains the pump at 345 kPa.
5. To purge, keep the pump at 345 kPa until maximum pumping
pressure is reached.
6. Open the return valve to send a pressure surge through the
loop to purge any air pockets in the piping system.
7. A noticeable drop in fluid level will be seen in the flush cart
tank. This is the only indication of air in the loop.
NOTE: If air is purged from the system while using a
254 mm PVC flush tank, the level drop will only be 25.4 to
50.8 mm since liquids are incompressible. If the level drops
more than this, flushing should continue since air is still being
compressed in the loop. If level is less than 25.4 to 50.8 mm,
reverse the flow.
8. Repeat this procedure until all air is purged.
9. Restore power.
Antifreeze may be added before, during or after the flushing pro-
cess. However, depending on when it is added in the process, it
can be wasted. Refer to the Antifreeze section for more detail.
Loop static pressure will fluctuate with the seasons. Pressures will
be higher in the winter months than during the warmer months.
This fluctuation is normal and should be considered when
charging the system initially. Run the unit in either heating or cool-
ing for several minutes to condition the loop to a homogenous
temperature.
When complete, perform a final flush and pressurize the loop to a
static pressure of 276 to 345 kPa for winter months or 103 to
138 kPa for summer months.
After pressurization, be sure to remove the plug from the end of
the loop pump motor(s) to allow trapped air to be discharged and
to ensure the motor housing has been flooded. Be sure the loop
flow center provides adequate flow through the unit by checking
pressure drop across the heat exchanger. Compare the results to
the data in Tables 27 and 28.
Table 27 — Water Coil Volume
50PC UNIT Coaxial Coil Volume
SIZE (gal)
009 0.08
012 0.08
015 0.09
018
0.14
024
0.24
030
0.24
036 0.27
042 0.27
048 0.49
060
0.62
070
0.62
Coaxial Coil Volume
(liters)
0.30
0.30
0.34
0.53
0.91
0.91
1.02
1.02
1.85
2.35
2.35
31
Table 28 — Water Side Pressure Drop
50PC UNIT WATER FLOW
SIZE RATE (l/s)
0.063
009 0.126
0.189
0.095
012
0.158
0.221
0.126
015 0.189
0.252
0.158
018
0.252
0.315
0.189
024 0.252
0.379
0.252
030
0.379
0.505
0.284
036 0.379
0.568
0.284
041
0.379
0.568
0.315
042 0.505
0.694
0.379
048
0.505
0.757
0.473
060 0.631
0.946
0.568
070
0.757
1.136
NOTE: All values based on pure water at 20.0°C.

Antifreeze

In areas where entering loop temperatures drop below 4.4°C or
where piping will be routed through areas subject to freezing, anti-
freeze is needed.
Alcohols and glycols are commonly used as antifreeze agents.
Freeze protection should be maintained to 9.5°C below the lowest
expected entering loop temperature. For example, if the lowest ex-
pected entering loop temperature is –1.1°C, the leaving loop tem-
perature would be –5.6 to –3.9°C. Therefore, the freeze protection
should be at –10.6°C (–1.1°C - –9.5°C = –10.6°C).
All alcohols should be pre-mixed and pumped from a reservoir
outside of the building or introduced under water level to
prevent fuming.
Calculate the total volume of fluid in the piping system. See Table
29. Use the percentage by volume in Table
amount of antifreeze to use. Antifreeze concentration should be
checked from a well mixed sample using a hydrometer to measure
specific gravity.
WATER SIDE
PRESSURE DROP (kPa)
3.4
11.7
24.2
7.1
17.9
32.8
12.9
26.8
45.0
7.9
18.5
27.6
11.5
19.3
40.0
13.9
28.7
48.2
10.7
17.9
37.2
10.7
17.9
37.2
13.7
31.8
56.5
5.6
9.3
19.4
9.5
16.0
33.2
13.8
23.2
48.2
30 to determine the