Marvair Scholar 2.0 I&S Manual 04/2022 Rev.2
46
Chapter 5: Scholar 2.0 Startup
5.01 START-UP PROCEDURE
CAUTION
THIS UNIT CONTAINS A CRANKCASE HEATER (CCH). FAILURE TO FOLLOW
INSTRUCTIONS REGARDING THE CCH AND STARTUP WILL VOID THE
MANUFACTURER’S WARRANTY.
CAUTION
FAILURE TO COMPLY COULD RESULT IN DAMAGE TO THE UNIT.
1. THIS SYSTEM HAS A MULTI-TAP CONTROL TRANSFORMER. REFER TO THE
WIRING DIAGRAM ON THE UNIT AND THIS MANUAL FOR THE CORRECT TAP TO
USE FOR YOUR INPUT VOLTAGE. FAILURE TO ENSURE THE PROPER PRIMARY
VOLTAGE TRANSFORMER CONNECTIONS MAY RESULT IN PREMATURE
COMPONENT FAILURE AND NUISANCE TRIPS.
2. SOME COMPRESSORS HAVE A CRANKCASE HEATER. FOR UNITS WITH
CRANKCASE HEATERS, POWER MUST BE ON FOR AT LEAST 24 HOURS BEFORE
OPERATING THE COMPRESSOR. WARRANTY WILL BE VOID IF NOT FOLLOWED.
3. FOR UNITS WITH SCROLL COMPRESSORS AND A 3Ø POWER SUPPLY, IT IS
IMPERATIVE THAT THE COMPRESSOR ROTATE IN THE PROPER DIRECTION.
REFER TO THE SECTION 1.12 OF THIS MANUAL TO VERIFY PROPER ROTATION.
A. On SCHOLAR 2.0 models with two stage compressors, only the cooling mode
operates in two stages. Mechanical heating (compressor) is a single stage as is the
dehumidification mode.
1. Turn the disconnect in the Scholar 2.0 unit to “OFF” position and double check
all electrical connections before applying power.
2. Set the remote thermostat system switch to “OFF” position. The blower switch
should be in “AUTO” position.
3. Check the voltage supply to the disconnect. If voltage readings are
appropriate, proceed with start-up. (See Figure 13 for acceptable voltage
ranges.) If voltage readings are not appropriate, check the power leads at the
disconnect and the main breaker in the mechanical room. Take appropriate
corrective action to supply sufficient voltage to the Scholar 2.0 disconnect.
Example: VDA2036HD
Voltage
Electrical Rating Designations*
A
C
D
Nominal Voltage
208/230
208/230
460
Phase
1
3
3
Minimum Voltage
197
197
414
Maximum Voltage
253
253
506
* Letters refer to model number code designations.
Table 2. Voltage Limitations
4. Turn the Scholar 2.0 heat pump disconnect to “ON” position.
5. Please refer to the thermostat instructions for configuration and start-up of units
with 2-stage compressors.
