Heat Controller VMH18SC-1, VMH12SC-1, VMH24SC-1 High evaporator coil temp.T2 protection, Auto-mode

Running mode

Cooling

Fan-only

Heating

Heat Controller, Inc. VMH Series Service Manual

8.4.3.5 High evaporator coil temp.T2 protection:

(1) T2>TEH2 compressor running frequency decreases to the lower level every 20s. If the frequency decreased to F2 and the T2 still over TEH2 for 3 minutes, the compressor will stop. If T2 deceased to lower than 118°F/48°C, or 118°F/48°C <T2< TEH2 last for 6 minutes, release the frequency limit control.

Unit	°F TEH2 (°C)
9K/12K	127°F	53°C
18K /24K	131°F	55°C

(2) If T2>140°F/0°C, the compressor stops and restarts when T2<118°F/48°C

8.4.4 Auto-mode

This mode can be selected by the remote control and the set temperature can be changed between 17~86°F/62°C.

In auto mode, the machine will select cooling, heating or fan-only mode according to the difference between T1 and Ts.

T1-Ts

T1-Ts＞1°F

-1< T1-Ts ≤1°F

T1-Ts ≤-1°F

Indoor fan will run in auto fan of the relevant mode.

The louver operates the same as in relevant mode.

If the machine switches mode between heating and cooling, the compressor will stop for 15 minutes and then choose mode according to T1-Ts again.

If the set temperature is modified, the unit will choose run function again.

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