Merco / Savory 86007, 86009 Service Manual

PARTS & SERVICE MANUAL

MHC-1 Holding Cabinet

Models 86007 & 86009

Model 86009 shown

P/N: L340134
REV: 5.13.08

Merco, LLC
1111 North Hadley Road
Fort Wayne, Indiana 46804
Telephone: [phone]
Fax: [phone]
Technical Support: 800.678.9511
mercosavory.com

UNIT SPECIFICATIONS

Model # Voltage Amps Watts Hz. Phase Plug

86007 (Left Side Control) 120 VAC 3 360 60 1 6’ NEMA 5-15P

86009 (Right Side Control) 120 VAC 3 360 60 1 6’ NEMA 5-15P

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SEQUENCE OF OPERATIONS

Power Supply

Heating Circuit

Electrical power is supplied to the unit by a 3
conductor service for single phase.
120VAC
Black conductor is hot.
White conductor is neutral.
Green and yellow conductor is ground.
Power is permanently supplied to the main power
switch.

Closing the main power switch supplies voltage to the
power board and control board. The control is set to
the desired temperature.
The control then intermittently supplies 120VAC
through the power board to the heater plates.
Temperature is then controlled by the two temperature
sensors sending a reference signal back to the control
board.

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TROUBLESHOOTING GUIDE

SYMPTOM POSSIBLE CAUSE EVALUATION

Holding Cabinet will
not heat

Power Switch Check continuity between switch terminals.
Power Board Make sure wires are connected properly including

Unit doesn’t reach
desired temperature
Heat Element Compare cavity temperature with display reading.

Check thermostat (common wire). Please note

Temperature is too
high
Heat Element Compare cavity temperature with display reading.

Incoming Power Supply Verify power cord is secured firmly in receptacle.

Measure the incoming voltage. Check circuit
breakers. Reset if required. Call power company
if needed.

Replace switch as needed.
ribbon cable. Check ground wire (green wires)

including main power cable. Make sure the unit is
grounded properly. If everything is right, replace
the control board.

Thermocouple Check for continuity in circuit.

Insert temperature probe into center of cavity.
Acceptable temperature variation is +/- 20° from
display reading.
Check for loose connection.
Check the Amp draw on each element for proper
load. Check page 2 for rating information. If the
amp draw is high or low, check the individual
elements for opens, shorts and proper resistance.
WITH POWER OFF: To check resistance of the
elements, remove all leads from the elements and
use a digital multimeter.
The element resistance should be as follows:
120V – 87 ohms
Replace heating element (shelf) as needed.

that if thermostat is bad, both circuits will be bad.

Thermocouple Check for incorrectly wired thermocouple.

Thermocouple wire polarities are reversed.
Insert temperature probe into center of cavity.

Acceptable temperature variation is +/- 20° from
display reading.
Check for loose connection.
Check the Amp draw on each element for proper
load. Check page 2 for rating information. If the
amp draw is high or low, check the individual
elements for opens, shorts and proper resistance.
WITH POWER OFF: To check resistance of the
elements, remove all leads from the elements and
use a digital multimeter.
The element resistance should be as follows:
120V – 87 ohms
Replace heating element (shelf) as needed.

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