ClimaCool UCA 20, Installation, Operation And Maintenance Manual

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Adjusting Unit Charge and Thermal Expansion
Valves Using Subcooling and Superheat Method
Due to varying installation conditions/applications and to
optimize performance, proper refrigerant charge
ƒ†–Š‡”ƒŽ‡š’ƒ•‹‘˜ƒŽ˜‡ȋȌƒ†Œ—•–‡–—•–
„‡ ‘Ƥ”‡†Ǥ
After checking compressor rotation, choose a circuit to be
–‡•–‡†Ƥ”•–Ǥ‘‡ ––‡•–‡“—‹’‡––‘‘‹–‘”–Š‡•— –‹‘
line and liquid line temperatures simultaneously. Place a
manifold gauge set on the suction line and liquid line then
start the compressor. As long as the suction pressure is high
enough to prevent the low pressure switch from tripping,
”—–Š‡ ‘’”‡••‘”ˆ‘”Ƥ˜‡‹—–‡•Ǥ
Verify proper subcooling. This is accomplished by
subtracting the liquid line temperature from the saturated
condensing temperature. The saturated condensing
temperature is found by converting the liquid line pressure
reading on the manifold gauge to the related temperature.
The normal subcooling temperature range at the condenser
is 5-15°F, BUT for total accuracy please follow the charge
recommendations found in the selection program. If
subcooling is too low, then refrigerant must be added to the
•›•–‡Ǥ†† Šƒ”‰‡ƒ†™ƒ‹–Ƥ˜‡‹—–‡•„‡ˆ‘”‡ Š‡ ‹‰
results. If subcooling is too high, then refrigerant must be
removed from the system.
Verify proper superheat by subtracting the saturated
evaporative temperature from the suction line temperature.
The saturated evaporative temperature is found by
converting the suction pressure reading on the manifold
gauge to the related temperature. The proper superheat
temperature range is 6-18°F at normal operating conditions
(typically 44
o
leaving chilled water temperature).
If superheat is low, this may indicate that the expansion
˜ƒŽ˜‡‹•‘˜‡”ˆ‡‡†‹‰Ǥ‘ƒ†Œ—•––Š‡‡š’ƒ•‹‘˜ƒŽ˜‡•ǡ
–—”–Š‡ƒ†Œ—•–‡–•–‡ Ž‘ ™‹•‡ǤŠ‹•™‹ŽŽ ƒ—•‡–Š‡
•—’‡”Š‡ƒ––‘”‹•‡Ǥƒ‹–Ƥ˜‡‹—–‡•„‡ˆ‘”‡ Š‡ ‹‰
–Š‡”‡•—Ž–•‘ˆ–Š‹•ƒ†Œ—•–‡–Ǥ‡’‡ƒ–—–‹Ž–Š‡†‡•‹”‡†
superheat is achieved.
 ‡ƒ†Œ—•–‡†ǡƒŽ•‘ Š‡ –Š‡†‹• Šƒ”‰‡‰ƒ••—’‡”Š‡ƒ–
ȋȌ–‘ ‘Ƥ””‡ƒ†‹‰‹•‘–Ž‡••–Šƒ͙͔η †‡‰”‡‡•
and the discharge line temperature is not more that 220°F
†‡‰”‡‡•Ǥ‘ Š‡ †‹• Šƒ”‰‡‰ƒ••—’‡”Š‡ƒ–ǡƤ”•–‘„–ƒ‹
the saturated condensing temperature by converting the
discharge pressure to saturated refrigerant temperature
using a pressure temperature chart. Next, measure
the discharge line temperature 6 to 10 inches from
the compressor. Subtract the saturated condensing
–‡’‡”ƒ–—”‡ˆ”‘–Š‡†‹• Šƒ”‰‡Ž‹‡–‡’‡”ƒ–—”‡–‘Ƥ†–Š‡
discharge gas superheat. If the DGSH is below 50°F degrees,
liquid refrigerant is still present in the suction gas vapor
returning to the compressor. The TXV will require additional
Ž‘ ™‹•‡ƒ†Œ—•–‡––‘”ƒ‹•‡–Š‡†‹• Šƒ”‰‡‰ƒ••—’‡”Š‡ƒ–
into the acceptable range.
Startup
18. Use refrigerant gauge set suitable for the high pressure
R-410A, and hook up to the suction and discharge
ports of each module’s compressor stages separately.
Bump start the compressors either by depressing
the contactor manually, or by using the manual run
commands from the Master Control Panel, (found in
the FN 7, or the service menu). Bump the compressor
only for 1-2 seconds to ensure the correct rotation of
the scroll compressors (indicated by a rising highside
pressure and a falling suction pressure).
19. Verify proper communications from each module back
to the master controller using the “STATUS” menu, then
indexing down to the desired compressor data screen.
• If the compressor data parameters all read “0”,
then communications are not yet established, and
communications cable troubleshooting is required.
• When all compressor data parameters read actual
values which agree with the refrigerant gauge set and
refrigerant line temperatures, then it is safe to
assume that communications are established.
20. Set up the master controller parameters according to
–Š‡•’‡ ‹Ƥ Œ‘„•—„‹––ƒŽ•Š‡‡–•Ǥ
• All parameters can be found in the FN 2 menu
(setup), FN 6 menu (module factory settings), FN 7
menu (service), FN 8 menu (master factory settings).
• It is imperative to access EVERY MENU and EVERY
PARAMETER to ensure all settings are appropriate.
21. Set up the Building Automation System (BAS) interface
parameters (as required) using the FN 0 menu (network
number selection, IP addressing), FN 4 menu
(device instances).