Heat Controller VMH18SC-1 - Page 24

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Service Manual VMH SerieS Heat Controller, Inc.
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8.4.2.2 Outdoor fan rules:
Outdoor fan and compressor start at the same time, outdoor fan stops 30s after the compressor stops.
The outdoor fan has two speeds, and is controlled by T4 as follows:
8.4.2.3 Indoor fan running rules
In cooling mode, indoor fan runs all the time and the speed can be selected as high, medium, low and auto.
Auto fan in cooling mode acts as follow:
8.4.2.4 Condenser high temperature T3 protection.
When 131°F/55°C <T3< 140°F/60°C, the compressor frequency will decrease to the lower level every 3
min until to F1 and then run at F1.
When T3<129°F/54°C the compressor will keep running at the current frequency.
When T3<126°F/52°C the compressor will not limit the frequency again and resume to the former
frequency.
When T3>140°F/60°C for 5 seconds, the compressor will stop and restart until T3<126°F/52°C.
T4
°F °C
72 (22)
68 (20)
T1-Ts
°F °C
7° (4.0)
5° (3.0)
3° (1.5)
2° (1.0)