Data Aire DAFC-11 Instrukcja Instalacji Pobierz pdf (Strona 20)

If the receiver (head) pressure is below 322 PSIG for R-410A (230 PSIG for R-407C), block part of

the condenser coil surface until the pressures rises to 322 PSIG for R-410A (230 PSIG for R-407C)

or greater. During extremely cold weather all the condenser fans may have to be de-energized to

maintain 322 PSIG for R-410A (230 PSIG for R-407C).

Observe the sight-glass on the receiver. Add refrigerant through the suction line until the level of

liquid in the receiver is approximately 1/3 from the bottom of the sight-glass (the leveling ball in the

receiver will start to ﬂ oat). At this point the charging is correct. Observing the receiver sight-glass

becomes difﬁ cult when they are remotely mounted near the condenser. The unit should be allowed

to stabilize for several minutes before meaningful measurements can be taken.

After the system is allowed to stabilize, the superheat at the compressor suction line (reading from

at least 6 inches from the compressor) should be 8 to 15°F. Units with remote condensing units

(DRCU), the superheat should be 20 to 25°F at the compressor. Remove any block that may have

been used on the condenser coil. If the ambient temperature while charging is below 70°F, some

of the refrigerant will be backed up into the condenser coil causing the liquid level in the receiver to

drop (this is normal).

NOTE: Charging to a full liquid line sight-glass should never be the sole means of de-

termining the correct refrigerant charge. Other parameters such as superheat, suction

pressure, head pressure, sub-cooling and ambient temperature are also important. A

system charged to a clear sight-glass is often overcharged.

4.3 Water/Glycol Cooled Systems

4.3.1 Water/Glycol Cooled System Charging

All water/glycol cooled units are factory charged with refrigerant. The water regulating valve should

be adjusted to maintain a condensing temperature of 105 to 119°F. Saturated suction temperature

should be 33°F or higher. The superheat at the compressor suction line (measured at least 6 inches

away from the compressor) should be 8 to 15°F.

Field charging water/glycol systems (if required) should be done by referring to the unit’s electrical

nameplate. The factory charge is indicated on the nameplate. Although this value represents the

original factory charge, it is still necessary to measure and note proper unit operation including su-

perheat, head and suction pressure. Some adjustment to the refrigerant may be required.

Adjust the refrigerant charge until the sight-glass clears or has sparse bubbles. The unit should

be allowed to stabilize for several minutes before meaningful measurements can be taken and the

conditioned space should be at or near the temperature setpoint.

All water/glycol cooled units have a water regulating valve. A head pressure sensing transducer is

connected to a shrader ﬁ tting on the discharge line and water is regulated into the condenser coil.

Standard condensers are plate ﬁ n type.

WARNING: Before starting a compressor, the crankcase heater should be energized

for a minimum of 12 hours to reduce the possibility of liquid slugging on start-up. Failure

to energize the crankcase heater could result in compressor damage. If the system is

charged from a vacuum, the pre-heating of the compressor is not necessary.

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Data Aire DAFC-11 Instrukcja Instalacji Strona 20