For the
Charge Verification
WARNING
REFRIGERANT UNDER PRESSURE!
•Do not overcharge system with refrigerant.
•Do not operate unit in a vacuum or at negative pres-
sure.
Failure to follow proper procedures may cause property damage, personal injury or death.
CAUTION
Use refrigerant certified to AHRI standards. Use of used refrigerant may cause compressor damage that is not covered under warranty. Most portable machines cannot clean used refrigerant to meet AHRI standards.
NOTICE
Violation of EPA regulations may result in fines or other penalties.
CAUTION
Operating the compressor with the suction valve closed may cause serious compressor damage.
Final Charge Adjustment
The outdoor temperature must be 60°F or higher. Set the room thermostat to COOL, fan switch to AUTO, and set the tem- perature control well below room temperature.
After system has stabilized per startup instructions, check subcooling and superheat as detailed in the following section.
Expansion Valve System
1.Purge gauge lines. Connect service gauge manifold
2.Temporarily install thermometer on liquid (small) line near liquid line service valve with adequate contact and insu- late for best possible reading.
3.Check subcooling and superheat. Systems with TXV ap- plication should have a subcooling of 11 ± 2 ºF and su- perheat of 9 ± 1 ºF.
a.If subcooling and superheat are low, adjust TXV to 9 ± 1 ºF superheat, then check subcooling.
NOTE: To adjust superheat, turn the valve stem clock- wise to increase and counter clockwise to decrease.
b.If subcooling is low and superheat is high, add charge to raise subcooling to 11 ± 2ºF then check superheat.
c.If subcooling and superheat are high, adjust TXV valve to 9 ± 1 ºF superheat, then check subcooling.
d.If subcooling is high and superheat is low, adjust TXV valve to 9 ± 1 ºF superheat and remove charge to lower the subcooling to 11 ± 2ºF.
NOTE: Do NOT adjust the charge based on suction pres- sure unless there is a gross undercharge.
4.Disconnect manifold set, installation is complete. Subcooling Formula = Sat. Liquid Temp. - Liquid Line Temp.
NOTE: Check the Schrader ports for leaks and tighten valve cores if necessary. Install caps
NOTE: Subsequent opening and replace of the cap will require only 1/2 to 1 hex flat. See the table below for the torque required for an effective seal on the valve bonnet (1/6 turn past finger tight.
TUBING SIZE | TORQUE |
5/8 | 14 |
1 3/8 | 16 |
After closing the valve bonnet, perform a final refrigerant leak test on the valves and sweat connections. Return the room thermostat to the desired settings.
Troubleshooting
Qualified Installer/Servicer Only
When troubleshooting, the first step should always be to check for clean coils, clean filter(s), and proper airflow. Indoor airflow should be 375 to 425 CFM per ton of cooling based on the size of the outdoor unit. The most common way of establishing indoor airflow is heating temperature rise. Indoor airflow will then be (Heating output of equipment) / (1.1 x temp. rise). In other cases, measurement of external static pressure is help- ful. For details, see the Installation Instructions for your indoor unit.
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