88-M4PW003-1B-EN
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Weigh-In Method can be used for the initial
installation, or anytime a system charge is being
replaced. Weigh-In Method can also be used
when power is not available to the equipment
site or operating conditions (indoor/outdoor
temperatures) are not in range to verify with the
subcooling charging method.
14.3 Weigh-In Method for Charging
Calculating Charge Using the Weigh-In Method
STEP 1 -
Measure in feet the distance between the
outdoor unit and the indoor unit and record on Line 1.
Include the entire length of the line from the service
valve to the IDU.
STEP 2 -
Enter the charge multiplier (0.6 oz/ft). Each
linear foot of interconnecting tubing requires the ad-
dition of 0.6 oz of refrigerant.
STEP 3 -
Multiply the total length of refrigerant tubing
(Line 1) times the value on Step 2. Record the result
on Line 3 of the Worksheet.
STEP 4 -
This is the amount of refrigerant to weigh-in
prior to opening the service valves.
1. Line length (ft)
______________
2. Charge multiplier
x ____0.6 ______
3. Step 1 x Step 2
= _____________
4. Refrigerant
=
_____________
1. Leak check refrigerant lines. ....................................... [ ]
2. Properly insulate suction lines and fittings.
.................. [ ]
3. Properly secure and isolate all refrigerant lines. .......... [ ]
4. Seal passages through masonry.
If mortar is used, prevent mortar from coming
into direct contact with copper tubing. .......................... [ ]
5. Verify that all electrical connections are tight. .............. [ ]
6. Observe outdoor fan during on cycle for clearance
and smooth operation................................................... [ ]
7. Be sure that indoor coil drain line drains freely. Pour water
Section 15. Checkout Procedures and Troubleshooting
15.1 Operational And Checkout Procedures
CHECKOUT PROCEDURE
After installation has been completed, it is recommended that the entire system be checked against the following list:
Final phases of this installation are the unit Operational and Checkout Procedures. To obtain proper performance, all units
must be operated and charge adjustments made.
Important:
Perform a final unit inspection to be sure that factory tubing has not shifted during shipment. Adjust tubing if nec-
essary so tubes do not rub against each other when the unit runs. Also be sure that wiring connections are tight and properly
secured.
into drain pan................................................................ [ ]
8. Be sure that supply registers and return grilles are open
and unobstructed.......................................................... [ ]
9. Be sure that a return air filter is installed.
..................... [ ]
10. Be sure that the correct airflow setting is used.
(Indoor blower motor) ................................................... [ ]
11. Operate complete system in each mode to
ensure safe operation................................................... [ ]
