Henny Penny MP-941 User Manual
Henny Penny
Multipurpose Holding Cabinet
Model MP-941
Model MP-942
Model MP-943
Model MP-944
TECHNICAL MANUAL
Model MP-941/942/943/944
TABLE OF CONTENTS
Section Page
Section 1. MAINTENANCE ............................................................................................................1-1
1-1. Introduction .............................................................................................................1-1
1-2. Safety ......................................................................................................................1-1
1-3. Test Instruments ......................................................................................................1-2
1-4. Error Codes .............................................................................................................1-2
1-5. Control Board..........................................................................................................1-3
1-6. Power Switch .........................................................................................................1-4
1-7. Transformer.............................................................................................................1-5
1-8. Relays ......................................................................................................................1-6
1-9. Heating Elements ....................................................................................................1-7
1-10. Temperature Probe ..................................................................................................1-8
1-11. Drawer Gasket ........................................................................................................1-9
1-12. High Limit (335˚ F) ................................................................................................1-10
1-13. Wiring Diagrams .....................................................................................................1-11
Section 5. PARTS INFORMATION ................................................................................................2-1
2-1. Introduction .............................................................................................................2-1
2-2. Genuine Parts ..........................................................................................................2-1
2-3. How To Order .........................................................................................................2-1
2-4. Prices .......................................................................................................................2-1
2-5. Delivery...................................................................................................................2-1
2-6. Warranty .................................................................................................................2-1
2-7. Recommended Spare Parts for Distributors ............................................................2-1
106 FM06-014 i
Revised 07-10-07
Model MP-941/942/943/944
Model MP-941/942/943/944
SECTION 1. MAINTENANCE
1-1. INTRODUCTION This section provides procedures for checking and
replacement of the various parts used within the cabinet.
1-2. SAFETY Where information is of particular importance or is safety
related, the words NOTICE, CAUTION, or WARNING are
used. Their usage is described below:
SAFETY ALERT SYMBOL is used with DANGER,
WARNING, or CAUTION which indicates a personal
injury type hazard.
NOTICE is used to highlight especially important
information.
CAUTION used without the safety alert symbol
indicates a potentially hazardous situation
which, if not avoided, may result in property damage.
CAUTION used with the safety alert symbol
indicates a potentially hazardous situation which, if
not avoided, may result in minor or moderate injury.
WARNING indicates a potentially hazardous
situation which, if not avoided, could result in
death or serious injury.
203 1-1
Model MP-941/942/943/944
1-3. TEST INSTRUMENTS You may use two test instruments to check the electrical
components.
1. A continuity light.
2. An ohmmeter.
When the manual refers to the circuit being closed, the
continuity light will be illuminated or the ohmmeter should
read zero unless otherwise noted. When the manual refers to
the circuit being open, the continuity will not illuminate or
the ohmmeter will read one or infinite resistance.
An ohmmeter must be used to check coils.
1-4. ERROR CODES
DISPLAY CAUSE PANEL BOARD CORRECTION
“E-4” Control board Turn switch to OFF position, then turn switch back to
overheating ON; if display shows “E-4”, the control board is
getting too hot; make sure unit is not overheating
“E-6” Faulty temperature Check to see if unit is set to the correct number of
probe drawers, ex: “MP-942=2” drawers (see Operation
and Programming Section in Operator’s Manual)
“E-41” Memory scrambled Press and release the UP and DOWN buttons to
initialize the program; if “E-41” persists replace the
control board
“Hi” Unit over-heating; Have relay or control board replaced
faulty relay or
control board
1-2 203
Model MP-941/942/943/944
1-5. CONTROL BOARD 1. Disconnect the electrical supply to the cabinet.
To avoid electrical shock or property damage,
move the POWER switch to OFF and disconnect
main circuit breaker, or unplug cord at wall
receptacle.
2. Remove the two screws on the front of the control
panel and pull control drawer out (Figure 1-1).
Figure 1-1
3. Using a 5/16" socket, remove nuts securing the board
and remove board from the panel (Figure 1-2).
Figure 1-2
4. Remove the connectors from the control board
(Figure 1-3).
5. Install new control board in reverse order.
Do not over-tighten the nuts securing the control
board, or the buttons on the controls may not
function.
Figure 1-3
103 1-3
Model MP-941/942/943/944
1-6. POWER SWITCH 1. Disconnect the electrical supply to the cabinet.
To avoid electrical shock or property damage,
move the POWER switch to OFF and disconnect
main circuit breaker, or unplug cord at wall
receptacle.
2. Remove the two screws on the front of the control
panel and pull control drawer out.
Mark the wires when removing them from the switch
to be sure the switch is rewired correctly.
3. Remove the wires from the switch (Figure 1-4).
Check for continuity across the top and bottom
Figure 1-4 terminals, on both left and right side of the switch.
With the switch in the ON position, the circuit should
be closed. With the switch in the OFF position, the
circuit should be open. If the switch is defective,
replace it by continuing with this section.
4. Squeeze the tabs on the back of the switch and pull
the switch out from the front of the panel
(Figure 1-5).
5. Install new POWER switch in reverse order.
Figure 1-5
1-4 203
Model MP-941/942/943/944
1-7. TRANSFORMER 1. Disconnect the electrical supply to the cabinet.
To avoid electrical shock or property damage,
move the POWER switch to OFF and disconnect
main circuit breaker, or unplug cord at wall
receptacle.
Figure 1-6 2. Remove the two screws on the front of the control
panel and pull control drawer out.
Before pulling the control panel out on the HC-944s,
remove the four screws securing the control box
(Figure 1-6).
3. Label wires and remove them from the transformer
(Figure 1-7).
Figure 1-7
4. Using a Phillips head screwdriver, remove the two
screws securing the transformer and remove the
transformer (Figure 1-8).
5. Install the new transformer in reverse order.
Figure 1-8
203 1-5
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