Corrective Maintenance - Lennox FLATAIR KFC Series Installation And Operating Manual

4.- MAINTENANCE

4.2.- CORRECTIVE MAINTENANCE

MAKE SURE THAT THE UNIT IS COMPLETELY DISCONNECTED FROM THE POWER SUPPLY
If some component in the cooling circuit must be replaced, follow these recommendations:
- Always use original replacement parts.
- Remove the entire refrigerant charge from the unit from through the schrader valves located in the
section. Create a slight vacuum as a safety measure.
- Regulation prohibits the release on the refrigerant into the atmosphere.
- If cuts must be made in the pipework, use pipe cutters. Do not use saws or any other tools that produce filings.
- All brazing must be carried out in a nitrogen atmosphere to prevent corrosion from forming.
- Use silver alloy brazing rod.
- Take special care that the flame from the torch is aimed in the opposite direction from the component to be
welded and is covered with a wet rag in order to avoid overheating.
Nitrogen
- Take very special care if 4-way check valves are to be replaced since these have internal components that
are very heat-sensitive such as plastic, teflon, etc.
- If a compressor must be replaced, disconnect it electrically and un-braze the suction and discharge lines. Remove
the securing screws and replace the old compressor with the new one. Check that the new compressor has the
correct oil charge, screw it to the base and connect the lines and electrical connections.
- Carry out the vacuum above and below through the schrader valves of the outdoor unit until -750 mm Hg is
reached.
Once this level of vacuum has been reached, keep the pump in operation for at least one hour. DO NOT USE
THE COMPRESSOR AS A VACUUM PUMP.
- Charge the unit with refrigerant according to the data on the Rating Plate for the unit and check that there are
no leaks.
PRECAUTIONS TO BE TAKEN IN THE USE OF R-407C Refrigerant
If R-407C Refrigerant is used in the unit, the following precautions characteristic of this gas should
be taken:
- The Vacuum Pump must have a Check Valve or Solenoid Valve.
- Pressure Gauges and Hoses for the exclusive use with R-407C Refrigerant should be used.
- The charge should be carried out in the Liquid Phase.
- Always use scales to weight-in charge- Use the Leak Detector exclusive for R-407C Refrigerant.
- Do not use mineral oil, nonly ynthetic oil to ream, expand or make connections.
- Keep pipes wcappedbefore using them and be very thorough about any possible dirt (dust, filings,
burrs, etc.).
- When there is a leak, gather what is left of the charge, create a vacuum in the unit and completely
recharge with new R-407C Refrigerant.
- WBrazingshould always be carried out in a nitrogen atmosphere.
- Reamers should always be well sharpened.
WHEN CARRYING OUT ANY TYPE OF WORK ON THE MACHINE
Wet rag
IMPORTANT
Direction of the flame
Silver alloy welding rod
Component to be welded
26
outdoor