Qmark MEDH - Portable Electric Blower Heaters - Manual (Page 3)

3
OPERATION INSTRUCTIONS
THERMOSTAT
Heaters include a bimetal thermostat for the automatic control
of the exiting air temperature. The thermostat knob controls the heating
elements and fan functions. The heater and fan are
de-energized with the knob in the extreme clockwise position.
Turning the knob clockwise from the off position to the fan
position will energize the fan only, for use in summer cooling.
The adjustment knob controls power to the heater and fan
when turned further in the clockwise direction, with the highest tempera-
ture setting in the extreme clockwise position.
The temperature setting in the heater mode is approximately
40°F in the low setting and 100°F at the highest setting.
Note: The adjustment knob should be turned to the fan only
setting after use for heating. The fan should be left on for at least 3 min-
utes to remove residual heat from the unit and to prevent overheating of
the housing.
Cord Preparation for Portable Heaters
1. Determine the gage and number of conductors fromChart A using
amps and phase from the heater nameplate. It is not recommended
that cord exceed 50 feet in length.
2. Strip off outer jacket of cord and insulation from lead wires. The tabu-
lation below provides the strip dimensions for the
various Chromalox portable heaters. See the nameplate on the heater
for the Model number.
3. Slide fitting onto cord and tighten knurled nut to secure fitting
to cord.
4. Select plug to match electrical rating of cord.
5. On opposite end of cord prepare end as directed by
instructions that are provided with the plug.
6. Attach cord assembly to heater as shown in Fig. 2 below:
Model No. A B C
All Models 8” 1” 0.5”
Figure 2
Run wire tie through slots in bracket and over cord.
Pull tab of wire tie to provide cord strain relief.
Power
wires
Ground
wire
90° fitting
"A"
"B" (Insulation strip dimension for ground wire).
"C" (Insulation strip dimension for power wires).
T3
T2
T1
L3
L2
L1
2
1 3
Thermostat
Cord by others.
Type "SO" or equal
sized to meet nameplate
requirements
4
1
3
5
6
Front of
Heater
6
5
4
3
2
1
Red
Motor
Blu
Blk
Wht
Cutout
6 4
Diag. 1 – FACTORY WIRED 3 PHASE
T2
T1
L2
L1
2
Cord by others.
Type "SO" or equal
sized to meet nameplate
requirements
4
1
3
5
6
Front of
Heater
6
5
4
3
2
1
All control wiring
same as Diag. 1
Instructions:
1. Loosen screws on load side of contactor. Remove all lead wire.
2. Insert lead wires numbers 1, 3, and 5 into box lug connector "T1". Tighten screws
on box lug connector.
3. Insert lead wires numbers 2, 4, and 6 into box lug connector "T2". Tighten screws
on box lug connector.
4. Examine wiring to make certain it is per above diagram.
Diag. 1a – FIELD CONVERSION TO 1 PHASE
All control wiring
same as Diag. 2
T2
T1
L2
L1
2
Cord by others.
Type "SO" or equal
sized to meet nameplate
requirements
4
1
3
5
6
Front of
Heater
6
5
4
3
2
1
All even numbered wires to T2
All odd numbered wires to T1
Contactor
Instructions:
1. Loosen screws on load side of contactor. Remove all lead wire.
2. Insert lead wires numbers 1, 3, and 5 into box lug connector "T1".
Tighten screws on box lug connector.
3. Insert lead wires numbers 2, 4, and 6 into box lug connector "T2".
Tighten screws on box lug connector.
4. Examine wiring to make certain it is per above diagram.
Diag. 2a – FIELD CONVERSION TO 1 PHASE
T3
T2
T1 L3
L2
L1
2
1 3
Thermostat
Cord by others.
Type "SO" or equal
sized to meet nameplate
requirements
4
1
3
5
6
Front of
Heater
6
5
4
3
2
1
Blk/Red or Grey
Motor
Blk
Wht
Cutout 6 4
Contactor 1 3
5
2 4 6
To T3
To T3
To T1 To T2 To T1
To T2
Fan Relay
A2
T2
T1
A1
L2
L1
XFMR
Blk
Black
White
Diag. 2 – FACTORY WIRED 3 PHASE
T3
T2
T1 L3
L2
L1
11
1 3
Thermostat
Cord by others.
Type "SO" or equal
sized to meet nameplate
requirements
9
10
7
8
12
Front of
Heater
10
9
4
3
2
1
Motor Blue
Cutout
6 4
Contactor
1
3
5
2
4
6
To T3
To T3
To T1
To T2 To T1
To T2
Red
Black
White
6
5
12
11 8
7
Diag. 3 – FACTORY WIRED 3 PHASE
MAINTENANCE INSTRUCTIONS
Replace or repair damaged cords or plugs immediately. Check
tightness of all electrical connections prior to energizing the
heater. Blow out or vacuum away any dirt or debries that may
have accumulated around the control enclosure fan motor or
heating elements.
Electric Shock Hazard. Disconnect heater from power supply
before servicing and/or inspecting the heater; failure to do so
may result in electrical shock.
a
WARNING
!