Lennox Magic-Pak PWC182 Installation And Maintenance Instructions Manual page 26

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The defrost controlwill initiate a defrosl cycle if the time period has elapsedand the defrost sensor detects a
temperature below freezfng. At the slart of the defrost cycle, Ihe defrost ControlwUIenergize the reversing valve
solenoid,shift(ng the reversing valve and de-energizing the outdoor fan. The defrost reraywilt alsoclose, energizing
auxiliary heat for increased comfortduring defrost. The unit will remain in thedefrost mode until the defrost sensor
has determined that lhe frost has been removed from the coil or a 10 minute time periodhas elapsed.
FIGURE3
OEFROST
TEST PINS
OEFROST
TIME JUMPER
T1 = 30 MINUTES
T2 = 60 MINUTES
T3 = 90 MINUTES
The defrost controlis alsoequipped with a set of testpinsto aid in troubleshooting of thedefrost system.The follow-
ing is a briefoutline of the testing of the defrost system.
The defrostsensorwilt be closedat 32 ° F or below. If temperatures are such that the switch is not closed,jumper
between the defrostsensorterminalson the defrostcontrol.
Start the systemin heating operation.
Jumper test pins. A 1/4" quick connectterminalcrimpedonto a solidwire or brazing rod workswell for testjumper.
Closing test pins speed up time interval by a factor of 256.
DEFROST CONTROL SETTINGDEFROST TEST CYCLETIME
T1-30 minutes 7 seconds
T2-60 minutes 14 seconds
T3-90 minutes 21 seconds
After closingtest pinsand appropriate cycle timehas elapsed,the reversing valveshouldshift to defrostmodeand
the outdoor fan should stop. Aftertwo secondsof defrostoperation, the reversing valve shouldshift back to heating
operation and the outdoor fan shouldstart.
SYSTEM PERFORMANCE
For maximumperformance of this heatpump system,the operatingtemperatures and pressureshouldbe checked
and superheat determined at Standard ARItest conditions of 82°F outdoor - 80°F indoor dry bulb/67°F wet burb. If
the superheat measured deviates from thevalues in the table below, the refrigerant charge shouldbe adjustedaccor-
dingly for maximum performance.
PWC SUCTIONSUPERHEAT -TABLE2
Outdoor Unit Model
PWC182
PWC242
SuctionSuperheat @ A.R.I. Conditions
18° . 20OF
17° - 19%