Fieldpiece HG2 - HVAC Guide System Analyzer User Manual

Page 23

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5.508 Charge unknown, raise indoor tempera-

ture to obtain a target superheat ≥ 5°F and
retest:

Since the test conditions are hot outside, dry

inside, or both, the exact target superheat cannot be
determined. Th

is non-TXV system may be correctly

charged or overcharged. It may be possible to open
windows or run the furnace to change the indoor
conditions enough to obtain a target superheat.

5.509 Possible overcharge, possibly remove re-

frigerant:

If no other conditions are triggered, con-

sider recovering refrigerant to correct. Th

e amount

of refrigerant necessary to recover will vary based on
the size of the system and the diff erence between Tar-
get and Actual superheat/subcooling.

5.510 Overcharged, remove refrigerant until

superheat reaches target superheat:

ere

is too much refrigerant in this non-TXV system. Re-
move refrigerant until the superheat is within ±5°F of
the target superheat. Th

e closer the superheat is to the

target, the better.

5.511 Overcharged, remove refrigerant until

subcooling reaches target subcooling:

ere

is too much refrigerant in this TXV/EXV system. Re-
move refrigerant until the subcooling is within ±3°F
of the target subcooling. Th

e closer the subcooling is

to the target, the better.

5.512 Undercharged, add refrigerant until sub-

cooling reaches target subcooling:

is TXV/

EXV system is low on refrigerant. Add refrigerant
until the subcooling is ±3°F of the target subcooling.
Th

e closer the subcooling is to the target, the better.

5.513 Overcharged, remove refrigerant until

actual subcooling reaches target subcool-
ing:

ere is too much refrigerant in the system. Th

amount of refrigerant necessary to recover will vary
based on the size of the system and the diff erence be-
tween Target and Actual subcooling.

5.514 Overcharged, remove refrigerant until

actual superheat reaches target superheat:

ere is too much refrigerant in the system. Th

amount of refrigerant necessary to recover will vary
based on the size of the system and the diff erence be-
tween Target and Actual superheat.

5.515 Possible low evaporator capacity:

evaporator is suspected of being unable to deliver the
cooling load necessary to maintain the desired indoor
conditions. Check the refrigerant charge (most com-
mon), clean the evaporator and/or condenser coils
and verify that the indoor airfl ow is correct.

5.516 Probable oversized metering orifi ce, con-

sult manufacturer’s specifi cations:

e me-

tering orifi ce is probably letting too much refriger-
ant through. Check that the orifi ce is sized properly.
Find the metering device part number and obtain the
orifi ce size from the manufacturer or distributor and
verify the size is appropriate for the air conditioner.

5.517 Probable undercharge, add refrigerant:

ere is probably insuffi

cient refrigerant in the sys-

tem. Th

e amount of refrigerant necessary to add will

vary based on the size of the system and the diff erence
between Target and Actual superheat/sub-cooling.

5.518 Superheat too high for TXV, check liquid

line for restriction:

If there is a liquid line restric-

tion then the TXV/EXV will be unable to maintain a
proper superheat. Make sure the service shut-off valves
are open. Check the liquid line for kinks or sections
that may have been stepped on or crushed. Check for
a large temperature diff erence between the liquid line
at the compressor and at the metering device.

5.519 Superheat too low for TXV, check TXV

to ensure proper functioning:

If the TXV/EXV

is not set properly, then the TXV/EXV will be unable
to maintain a proper superheat. Check that the TXV/
EXV bulb is adjusted to the proper superheat, and is in
good contact with the suction line and insulated from
the environment.