12
Step 13.—Check Charge
Factory charge and charging method are shown on unit rating
plate. To check char ge in cooling mode, refer to Cooling Only
Procedure. To check charge in heating mode, refer to Heating
Check Chart Procedure.
With unit operating, charge Puron units with liquid using a
commercial type metering device in manifold hose. Charge
refrigeran t in to su ctio n lin e. So m e refrigeran t cylin d ers may
contain a dip tube that allows liquid refrigerant to flow from
cylinder in upright position. Check cylinder label for correct
position to allow liquid flow.
COOLING ONLY
PROCEDURE
NOTE: If subcooling charging conditions are not favorable,
charge must be weighed in accordance with unit rating plate,
±0.6 oz/ft of 3/8 in. liquid line above or below 15 ft,
respectively. Favorable conditions fall within the ranges given on
the charging chart on the outdoor unit plate.
EXAMPLE:
To calculate additional charge required for a 25---ft. line set:
25 f t. --- 15 f t. = 10 ft. X 0.6 oz /ft. = 6 oz. of additional
charge.
Units installed with cooling mode TXV require charging with the
subcooling method.
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure liquid service valve pressure by attaching an accurate
gage to service port.
3. Measure liquid line temperature by attaching an accurate
thermistor type or electronic thermometer to liquid line near
outdoor coil.
4. Refer to unit rating plate for required subcooling temperature.
5. Refer to Table 4. Find the point where required subcooling
temperature intersects measured liquid service valve pressure.
6. To obtain required subcooling temperature at a specific liquid
line pressure, add refrigerant if liquid line temperature is higher
than in d i cated or reclaim refrigeran t if tem p erature i s low er.
Allow a tolerance of ± 3°F.
HEATING CHECK CHART
PROCEDURE
To check system o p eratio n du rin g h eatin g cy cle, refer to the
Heating Check Chart on outdoor unit. This chart indicates
whether a correct relationship exists between system operating
pressure and air temperature entering indoor and outdoor units. If
pressure and temperature do not match on chart, system
refrigerant charge may not be correct. Do not use chart to adjust
refrigerant charge.
NOTE: In heating mode, check refrigerant charge only when
pressures are stable. If in doubt, remove charge and weigh in
correct refrigerant charge.
NOTE: When charging is necessary during heating season,
charge must be weight in accordance with unit rating plate ±0.6
oz/ft of 3/8 in. liquid line above or below 15 ft, respectively.
EXAMPLE:
To calculate additional charge required for a 25---ft. line set:
25 f t. --- 15 f t. = 10 ft. X 0.6 oz /ft. = 6 oz. of additional
charge.
Step 14.—Final Checks
IMPORTANT : Before leaving job, be sure to do the following:
1. Ensure that all wiring is routed away from tubing and sheet
metal edges to prevent rub --through or wire pinching.
2. Ensure that all wiring and tubing is secure in unit before
adding panels and covers. Securely fasten all panels and covers.
3. Tighten service valve stem caps to 1/12-- turn past finger tight.
4. Leave Users Manual with owner. Explain system operation
and periodic maintenance requirements outlined in manual.
5. Fill out Dealer Installation Checklist and place in customer
file.
CARE AND MAINTENANCE
For continuing high performance and to minimize possible
equipment failure, periodic maintenance must be performed on
this equipment.
Frequency of maintenance may vary depending upon geographic
areas, su ch as coastal app lication s. S ee Users Man ual for
information.
25HBA
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