Rheem RHMV2421MNACJA Service Manual page 134

3. DEFROST FLOWCHART
Defrosting shall proceed by integrating operation time,
outdoor temperature and outdoor condenser coil temperature as below.
RP1724HJVXA
RP1730HJVXA
1st defrost
Compressor Compressor
integrating integrating
operation: operation:
Over 17 minutes Over 57 minutes
Tn ≤ 15.8°F (-9°C)
Tn ≤ 23°F (-5°C)
and
Ta - Tn ≥ 41°F (5°C)
(and after 5 minutes
(and after 5 minutes
in 23 °F(- 5°C))
in 41°F (5°C))
Heating operation start : Compressor ON
2nd or later defrost
Compressor
integrating
operation:
Over 35 minutes
Tn < -13°F (-25°C)
①
Tn - Tn10 < 9°F (-5°C)
②
( Tn ≤ 21.2°F (-6°C))
③ Tn - Tnb < -3.6°F (-2°C)
( Tn ≤ 21.2°F (-6°C))
Defrost Indicator:
[Operation lamp]
6 sec ON / 2 sec OFF
Outdoor condenser coil temperature: Over
or
Compressor ON time: Maximum 15 minutes
(Not defrosted for 10 minutes)
Compressor
integrating
operation:
Over 210 minutes
Tn ≤ 26.6°F (-3°C)
(and after 30 minutes
in 26.6 °F(- 3°C))
Tn : Outdoor condenser coil temperature.
Ta : Outdoor temperature.
Defrost start
Tn10 : Temperature of continuous operation at 10 minutes.
Tnb : Back 5 minutes temperature.
Compressor : OFF
Outdoor fan motor : OFF
30 sec later 4-way valve : OFF
35 sec later compressor : ON
55.4° F(13°C)
Defrost end
04-26
Integrating defrost
Compressor
integrating
operation:
Over 210 minutes
Tn ≤ 23°F (-5°C)
(and after 5 minutes
in 23 °F(- 5°C))
Integrating defrost
(OFF count defrost)
Compressor
OFF count :
40 times
(Less than
10 minutes)