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Page 23

XP21 SERIES

Professional Maintenance

Your heating and air conditioning system should be in­
spected and maintained twice each year (before the start
of the cooling and heating seasons) by a licensed profes­
sional HVAC technician. You can expect the technician to
check the following items. 

These checks may only be

conducted by a licensed professional HVAC techni­
cian.

Outdoor Unit

1. Inspect component wiring for loose, worn or damaged

connections. Also check for any rubbing or pinching of
wires. Confirm proper voltage plus amperage of out­
door unit.

2. Check the cleanliness of outdoor fan and blade condi­

tion (cracks) and clean or replace them, if necessary.

3. Inspect base pan drains for debris and clean as neces­

sary.

4. Inspect the condition of refrigerant piping and confirm

that pipes are not rubbing copper-to-copper. Also,
check the condition of the insulation on the refrigerant
lines. Repair, correct, or replace as necessary.

5. Test capacitor. Replace as necessary.

6. Inspect contactor contacts for pitting or burn marks.

Replace as necessary.

7. Check outdoor fan motor for worn bearings/bushings.

Replace as necessary.

8. Inspect and 

clean 

outdoor coils, if necessary and note

any damage to coils or signs of leakage.

Indoor Unit (Air Handler or Furnace)

1. Inspect component wiring for loose, worn or damaged

connections. Confirm proper voltage plus amperage
of indoor unit.

2. Inspect and clean or replace air filters in indoor unit.

3. Check the cleanliness of indoor blower and clean

blower, if necessary.

4. Inspect the indoor coil drain pans and condensate

drains for rust, debris, obstructions, leaks or cracks.
Pour water in pans to confirm proper drainage from the
pan through to the outlet of the pipe. Clean or replace
as necessary.

5. Inspect and clean indoor coil, if necessary.

6. Inspect the condition of the refrigerant lines and con­

firm that pipes are not rubbing copper-to-copper. Also,
ensure that refrigerant pipes are not being affected by
indoor air contamination. Check condition of insulation
on the refrigerant lines. Repair, correct, or replace as
necessary.

7. Inspect the duct system for leaks or other problems.

Repair or replace as necessary.

8. Check for bearing/bushing wear on indoor blower mo­

tor.  Replace as necessary.

9. If your heat pump is matched with a gas- or oil-fired fur­

nace for auxiliary heating, indoor unit service will also
include inspection and cleaning of the burners, and a
full inspection of the gas valve, heat exchanger and
flue (exhaust) system.

General System Test with System Operating

1. Your technician should perform a general system test.

He will turn on the air conditioner to check operating
functions such as the start­up and shut­off operation.
He will also check for unusual noises or odors, and
measure indoor/outdoor temperatures and system
pressures as needed. He will check the refrigerant
charge per the charging sticker information on the out­
door unit.

2. Verify that system total static pressure and airflow set­

tings are within specific operating parameters.

3. Verify correct temperature drop across indoor coil.

Summary of Contents for XP21 Series

Page 1: ...nd service must be performed by a licensed professional installer or equivalent or service agency CAUTION Before attempting to perform any service or mainte nance turn the electrical power to unit OFF...

Page 2: ...18 1 2 470 8 203 1 25 4 7 16 113 LIQUID LINE INLET VAPOR LINE INLET ELECTRICAL INLETS BASE WITH ELONGATED LEGS SIDE VIEW ACCESS VIEW DISCHARGE AIR 37 940 024 THRU 036 47 1194 048 AND 060 16 7 8 429 8...

Page 3: ...nts from dryers water heaters and furnaces should be directed away from the outdoor unit Prolonged exposure to exhaust gases and the chemicals contained within them may cause condensation to form on t...

Page 4: ...ze barrier at least the same height and width as out door unit Install barrier 24 inches 610 mm from the sides of the unit in the direction of prevailing winds 24 610 WIND BARRIER PREVAILING WINTER WI...

Page 5: ...efore unit start up to pre vent compressor damage as a result of slugging CAUTION ELECTROSTATIC DISCHARGE ESD Precautions and Procedures Electrostatic discharge can affect electronic components Take c...

Page 6: ...wires between the thermostat and the furnace air handler con trol and four wires between the outdoor unit and the furnace air handler control When a thermostat cable with more than four wires is used...

Page 7: ...E TARGET 40 DEGREE TARGET DEFAULT 55 50 45 40 55 50 45 40 55 50 45 40 55 50 45 40 DEGREE TARGET 100 90 DEGREE TARGET 70 DEGREE TARGET 50 DEGREE TARGET 90F 70F 50F TARGET 90F 70F 50F 90F 70F 50F 100F 9...

Page 8: ...d up on the fan blade and orifice ring is when the outdoor ambient is below 35 F and the unit is OFF for more than 30 minutes PREVIOUS TERMINATION TEMPERATURE TERMINATION TEMPERATURE FOR NEXT DEFROST...

Page 9: ...t s o r f e d l l i w n o i t a n i m r e t g n i t t e s 1 J e h t w o l l o f m u m i x a M E T O N r o f d e w o l l a e m i t s e t u n i m 4 1 s i t s o r f e d See table on Page 10 Next defrost...

Page 10: ...eached the specified defrost termination temperature in less than 14 minutes Termination temperature set on outdoor control is 50 F 70 F 90 F or 100 F Defrost for 14 minute maximum without the coil te...

Page 11: ...isplay optional 2 R to L connection is required for this model when using the ComfortSense 7000 catalog number Y0349 only Resistor Kit catalog number 47W97 required and ordered separately 3 Air handle...

Page 12: ...tage operation 5 Cut loop jumper clippable wire Short DS to R for Humiditrol applications This will slow the outdoor unit s fan speed to a specific RPM A wire must be installed between the DS terminal...

Page 13: ...nox units charged with HFC 410A refrigerant Residual mineral oil can act as an insulator preventing proper heat transfer It can also clog the expansion device and reduce sys tem performance and capaci...

Page 14: ...oor unit s liquid line orifice housing LOW HIGH EXISTING INDOOR UNIT GAUGE MANIFOLD CYLINDER CONTAINING CLEAN HCFC 22 TO BE USED FOR FLUSHING Positioned to deliver liquid refrigerant LIQUID LINE SERVI...

Page 15: ...itrogen flow will have an exit point NITROGEN HIGH LOW B A C PIPING PANEL REMOVAL PREPARING LINE SET CAP AND CORE REMOVAL Remove piping panel to access service valves Cut ends of the refrigerant lines...

Page 16: ...ater saturated cloths under the valve body to protect the base paint 4FLOW NITROGEN Flow regulated nitrogen at 1 to 2 psig through the refrigeration gauge set into the valve stem port connection on th...

Page 17: ...KIT MATCH UPS AND APPLICATION INFORMATION A REMOVE THE FIELD PROVIDED FITTING THAT TEMPORARILY RECON NECTED THE LIQUID LINE TO THE INDOOR UNIT S DISTRIBUTOR AS SEMBLY B INSTALL ONE OF THE PROVIDED TEF...

Page 18: ...der of HFC 410A refrigerant to the center port of the manifold gauge set Open the valve on the HFC 410A cylinder vapor only B Open the high pressure side of the manifold to allow HFC 410A into the lin...

Page 19: ...ge caused by deep vacuum operation will void warranty OUTDOOR UNIT TO VAPOR SERVICE VALVE TO LIQUID LINE SERVICE VALVE MICRON GAUGE VACUUM PUMP A34000 1 4 SAE TEE WITH SWIVEL COUPLER 500 MANIFOLD GAUG...

Page 20: ...30 minutes minimum at the deep vacuum level Deep Vacuum Gauge Response and System Conditions FIGURE 19 Triple Evacuation Method The triple evacuation method should only be used when system does not c...

Page 21: ...ting to the outside coil tub ing The location of the coil sensor is important for proper defrost operation NOTE The heat pump control accurately measures the performance of the system as frost accumul...

Page 22: ...els must be in place any time the unit is in operation If you are unsure about the filter required for your system call your Lennox dealer for assistance IMPORTANT Sprinklers and soaker hoses should n...

Page 23: ...unit 3 Check the cleanliness of indoor blower and clean blower if necessary 4 Inspect the indoor coil drain pans and condensate drains for rust debris obstructions leaks or cracks Pour water in pans...

Page 24: ...ies with Y2 out terminal on the outdoor control 5 Cycle main power ON 6 Allow pressures and temperatures to stabilize before taking any reading may take up to 10 minutes 7 Record all of the readings f...

Page 25: ...st Stage Expected results during Y2 demand toggle switch ON Y2 Second Stage Compressor Voltage Same Same Amperage Higher Higher Condenser Fan motor Amperage Same or Higher Same or Higher Temperature A...

Page 26: ...ure Return Air Temperature HEATING MODE Vapor Pressure Liquid Pressure Supply Air Temperature Ambient Temperature Return Air Temperature System Refrigerant Charge Refer to manufacturer s information o...

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