AHC-993
Henny Penny
Humidied Holding Cabinets
With Automatic Water Fill
Model AHC-993
Model AHC-990
TECHNICAL MANUAL
Model AHC-990/993
i
TABLE OF CONTENTS
Section Page
Section 1. TROUBLESHOOTING
1-1. Introduction ................................................................................................................. 1-1
1-1. Safety ........................................................................................................................... 1-1
1-3. Troubleshooting ........................................................................................................... 1-1
1-4. Error Codes and Warnings ........................................................................................... 1-5
1-5. Info Mode .................................................................................................................... 1-8
Section 2. LEVEL 2 PROGRAMMING
2-1. Introduction ................................................................................................................. 2-1
2-2. Tech Mode ................................................................................................................... 2-1
2-3. Stats Mode ................................................................................................................... 2-5
2-4. Data Logging and Manufacturing Mode ..................................................................... 2-8
Section 3. MAINTENANCE
3-1. Introduction ................................................................................................................. 3-1
3-2. Maintenance Hints ....................................................................................................... 3-1
3-3. Humidity Sensor Calibration and Replacement .......................................................... 3-1
3-4. Power Switch Replacement ......................................................................................... 3-4
3-5. Air Temperature Probe Replacement .......................................................................... 3-5
3-6. Transformer Replacement ........................................................................................... 3-7
3-7. Relay Replacement ...................................................................................................... 3-8
3-8. Module Top Removal .................................................................................................. 3-9
3-9. Cooling Fan Replacement ........................................................................................... 3-10
3-10. High Limit - Air Heater Replacement ......................................................................... 3-10
3-11. Blower Motor Replacement ........................................................................................ 3-11
3-12. Air Heater Replacement .............................................................................................. 3-12
3-13. Speaker Replacement .................................................................................................. 3-12
3-14. Complete Panel or PC Board Replacement ................................................................. 3-13
3-15. Float Switch Replacement ........................................................................................... 3-14
3-16. High Limit - Water Heater Replacement ..................................................................... 3-15
3-17. Water Pan Heater Replacement ................................................................................... 3-16
3-18. Solenoid Valve and Water Strainer Replacement ........................................................ 3-19
3-19. Door Gasket Replacement ........................................................................................... 3-20
3-20. Vent Motor Replacement ............................................................................................. 3-20
3-21. Vent Motor Microswitch Replacement ........................................................................ 3-21
3-22. HC-993 Flip Door Replacement .................................................................................. 3-22
Wiring Diagrams ......................................................................................................... 3-24
Section 4. PARTS INFORMATION
4-1. Introduction ................................................................................................................. 4-1
4-2. Genuine Parts............................................................................................................... 4-1
4-3. When Ordering Parts ................................................................................................... 4-1
4-4. Prices ........................................................................................................................... 4-1
4-5. Delivery ....................................................................................................................... 4-1
4-6. Warranty ...................................................................................................................... 4-1
4-7. Recommended Spare Parts for Distributors ................................................................ 4-1
Parts List ...................................................................................................................... 4-2
FM06-045
Revised 4/16/2015 RS
Model AHC-990/993
1-1
This section provides troubleshooting information in the form
of an easy to read table.
If a problem occurs during the rst operation of a cabinet,
recheck the installation per the Installation Section of the Op-
erator’s Manual
Before troubleshooting, always recheck the operation proce-
dures in the Operator’s Manual.
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 po-
tentially hazardous situation which, if not avoided, may result
in property damage.
CAUTION used with the safety alert symbol indicates a po-
tentially 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.
To isolate a malfunction, proceed as follows:
1. Clearly dene the problem or symptom and when it occurs.
2. Locate the problem in the troubleshooting table.
3. Review all possible causes. Then, one at a time work
through the list of corrections until problem is solved.
If maintenance procedures are not followed correctly,
injuries and/or property damage could result.
SECTION 1. TROUBLESHOOTING
1-1. INTRODUCTION
1-3. TROUBLESHOOTING
1-2. SAFETY
Feb. 2011
Model AHC-990/993
1-2
1-3. TROUBLESHOOTING (continued)
Problem Cause Correction
OPERATION
A. Product not • Doors left open • Keep doors closed except
holding temperature to load and serve product
• Product held too long • Hold product only for
recommended times
• Control temperature set too low • Increase air temperature
setpoint (SP-3) in Special
Program Mode
• Bad air heater • Check heaters and replace if bad
See Tech Mode items 10 and 16
• Blower not working • Check blower and replace if bad
See Tech Mode item 18
• Bad air heater, or blower relays • Replace relay
See Tech Mode items 10 and 16
• Bad high limit • Check high limit and replace if
bad
• Low or improper voltage • Compare receptacle voltage to
data plate voltage
• Door gasket torn or worn • Replace bad door gaskets
• Air probe faulty, open (“E-6A”), • Ohm out the probe and replace
or shorted (“E-6B”) if necessary
B. Cabinet steaming • Humidity setpoint too high • Decrease humidity setpoint
or product soggy (SP-4) in Special Program Mode
• Water heater probe faulty, open • Ohm out the probe and replace
(“E-12A”), or closed (“E-12B”) if necessary
• Bad humidity sensor (“E-17”) • Replace humidity sensor
• Relay stuck closed • Replace relay
• Vent stuck closed (“E-80”) • Bad vent motor - replace
• Bad vent motor relay - replace-
See Tech Mode item 18
• Check alignment and condition
of mechanical vent parts
• Vent acorn nuts too tight, loosen
if necessary
Feb. 2011
Model AHC-990/993
1-3
OPERATION (Continued)
C. Product dry • Bad oat switch • Replace oat switch
• Bad water heater high limit • Replace high limit
• Bad water heater • Check heater and replace if bad;
see Tech Mode item 18
• Humidity setpoint too low • Increase humidity setpoint
(SP-4) in Special Program Mode
• No water in pan • Turn water supply on
• Adjust ow control valve
• Check solenoid valve and relay
• Vent stuck open (“E-80”) • Bad vent motor - replace; see
Tech Mode item 18
• Bad vent motor relay - replace
• Check alignment and condition
of mechanical vent parts
HEATING SYSTEM
A. Unit not heating • Bad control board • Replace control board
• Bad high limit • Check high limit; replace if bad
• Bad air heater or blower relays • Replace relay
• Bad air heater • Check heaters and replace if bad;
see Tech Mode item 18
• Faulty wiring • Check for loose connections or
broken wires
B. Unit not reaching set • Blower not working. • Check Blower and replace if bad;
temperature see Tech Mode item 18
• Bad air heater • Check heaters and replace if bad;
see Tech Mode item 18
• Bad air heater, or blower relays • Replace relay
• Doors left open • Keep doors closed except
to load and serve product
• Door gasket torn or worn • Replace bad door gaskets
1-3. TROUBLESHOOTING (continued)
Problem Cause Correction
Feb. 2011
Model AHC-990/993
1-4
C. Unit Overheating • Blower not working • Check blower and replace if bad
(“E-5”) See Tech Mode item 18
• Bad control board • Replace control board
• Relay stuck closed • Replace relay
1-3. TROUBLESHOOTING (continued)
Problem Cause Correction
HEATING SYSTEM (Continued)
Feb. 2011
Model AHC-990/993
1-5
1-4. ERROR CODES AND The display shows the following error codes and warnings when a
WARNINGS fault is detected, along with an alarm sound. Both the heat and
humidity systems shut down, except when specied otherwise.
Display Cause Panel Board Correction
“E-4 CPU TOO HOT” • Control board too hot;
unit overheating or
louvers clogged
“E-5 AIR TEMP TOO HOT” • Faulty relay, PC board,
or air probe
“E-54A CPU TEMP SENSOR • Faulty PC board
OPEN”
“E-54B CPU TEMP SENSOR • Faulty PC board
SHORTED”
“E-6A AIR TEMP SENSOR • Faulty air probe
FAILED OPEN”
• Turn switch to OFF position, then back
to ON; if display still shows “E-4”, PC
board is getting too hot; clean louvers
and check cooling fan; if cooling fan is
not working, have it replaced; once
panel cools down, the controls should
return to normal; if “E-4” persists, have
the PC board replaced
• Turn switch to OFF position, then back
to ON; if display shows “E-5”, heating
circuits and temperature probe should
be checked; once the unit cools down,
the controls should return to normal; if
“E-5” persists, have PC board replaced
• Turn switch to OFF position, then back
to ON; if display shows “E-54A”, the
control should be re-initialized (see Pro-
gramming Section); if the error code
persists, have PC board replaced
• Turn switch to OFF position, then back
to ON; if display shows “E-54B”, the
control should be re-initialized (see Pro-
gramming Section); if the error code
persists, have PC board replaced
• Turn switch to OFF position, then back
to ON; if the display shows “E-6”, the
temperature probe should be checked;
once the temperature probe is repaired,
or replaced, the controls should return
to normal; if “E-6” persists, have the PC
board replaced
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“E-6B AIR TEMP SENSOR • Faulty air temperature
FAILED SHORTED” probe
“E-12A WATER HEATER • Faulty water
SENSOR FAILED heater probe
OPEN”
“E-12B WATER HEATER • Faulty water
SENSOR FAILED heater probe
CLOSED”
“E-17 HUMIDITY SENSOR • Faulty humidity sensor
FAILED”
“E-41 SYSTEM DATA LOST”
• Memory scrambled
A humidity error only shuts down the humidity system. If a humidity error occurs, and you want to use
the cabinet without humidity, turn the humidity off by following the directions for SP-4, Humidity Set-
point, in Special Programming Section of this manual. Once the setpoint is off, the alarm stops, but the
error code shows in display. (Includes “E-12A”, “E-12B”, and “E-17”).
1-4. ERROR CODES AND
WARNINGS (Continued)
Display Cause Panel Board Correction
• Turn switch to OFF position, then back to
ON; if the display shows “E-6”, the
temperature probe should be checked;
once the temperature probe is repaired, or
replaced, the controls should return to
normal; if “E-6”persists, have PC board
replaced
• Turn switch to OFF position, then back to
ON; if the display shows “E-12A”, the
water heater should be checked and
repaired or replaced (the water heater
probe is built into the water heater); the
controls should return to normal; if
“E-12A” persists, have PC board replaced
• Turn switch to OFF position, then back to
ON; if the display shows “E-12B”, the
water heater should be checked and
repaired or replaced (the water heater
probe is built into the water heater); the
controls should return to normal; if
“E-12B” persists, have PC board replaced
• Turn switch to OFF position, then back to
ON; if the display shows “E-17”, the
humidity sensor should be checked;
once the humidity sensor is repaired, or
replaced, the controls should return to
normal; if “E-17” persists, have PC board
replaced
• Turn switch to OFF position, then back
to ON; if the display shows “E-41”, the
control should be re-initialized (see Pro-
gramming Section); if “E-41”persists,
have PC board replaced
Feb. 2011
Model AHC-990/993
1-7
1-4. ERROR CODES AND
WARNINGS (Continued)
“E-46 DATA SAVE FAILED” • Memory scrambled
“E-80 VENT STUCK OR • V ent on rear of module
BAD SWITCH” stuck or faulty vent
activation switch
“WATER LEVEL LOW, • Water pan low on
PLEASE ADD WATER” water or empty
(Appears only if ll option is
set to Manual)
“WATER PAN NOT FILLING, • Water supply turned
CHECK WATER SUPPLY” off
(Appears only if ll option is
set to Auto) • Water ow reduced
• Fill solenoid relay bad
• Fill solenoid bad
“CALL SERVICE, WATER • Faulty relay or heater
HEATER FAILURE”
• Turn switch to OFF position, then back
to ON; if the display shows “E-46”, the
control should be re-initialized (see Pro-
gramming Section); if “E-46”persists,
have PC board replaced
• Check vent on rear of module for
obstructions, or have vent activation
switch replaced
• Vent acorn nuts too tight; loosen if
necessary
• Fill water pan, in bottom of unit, to the
maximum water ll mark; this warning
won’t shut down the heat or humidity
• Turn water supply on
• Adjust ow control valve
• Check solenoid relay
• Check solenoid valve
• Check heater relay and heater
Display Cause Panel Board Correction
March 2014
“PURGE” Unit is purging humidity No correcting action needed. If message
continues, contact the Henny Penny Tech-
nical Support Line at 1-800-417-8405
Model AHC-990/993
1-8
1-5. INFO MODE
This mode records historic information on the holding cabinet
and operator performance, which could help in troubleshooting
a problem.
This mode records historic information on the unit and operator
performance. Press and at the same time and
“*INFO MODE*” shows on display. Press or to
access the steps and press to view the statistics within
each step.
Information Mode is intended for technical use, but the opera-
tor can view the following information:
1. Error Log - last 10 errors and time they occurred
2. Power Up Log - time of last 10 power-ups
3. Outputs/Inputs - shows the state of unit’s inputs and
outputs
a. OUT V_S_F_W_A_ (vent motor, ll solenoid valve, fan,
water heater, air heater, relay order from left to right)
b. AMPS V_S_F_W_A_
c. NC/GD V_S_F_W_A_ (no connect/ground detection on
outputs to relays)
d. All outputs and inputs V_S_F_W_A_ P_ (power switch
input) E_(exhaust vent switch input) F_ (oat switch
input)
4. Vent - open or closed
5. CPU temperature
6. Cabinet air temperature
7. Water heater temperature
8. Food probe temperature
9. Humidity counts value
10. Humidity value
11. Water heater conditions
12. Analog inputs
1. E-LOG (error code log)
Press and “A. (time) *NOW*” shows in display.
This is the present date and time.
Press and if a error was recorded, “B. (date, time, and
error code information)” shows in display. This is the latest
error code that the controls recorded.
Press and the next latest error code information can
be seen. Up to 10 error codes (B to K) can be stored in the
E-LOG section.
Feb. 2011
Model AHC-990/993
1-9
Press to continue to P-LOG.
2. P-LOG (power-up log)
Press and “A. (time) *NOW*” shows in display.
This is the present date and time.
Press and the latest power-up is shown, “B. (date, time,)
PWR-UP”.
Press and the next latest power-up date is shown. Up to
10 power-ups (B to K) can be stored in the P-LOG section.
Press to continue onto the Outputs/Inputs.
3. OUTPUTS/INPUTS
This mode displays the status of components and inputs. If
the input or output signal is detected, an identifying letter is
displayed (see below). If the signal is not detected, “_” is
displayed. Press to view the following:
a. “3. OUT V_S_F_W_A_” shows in the display. If the
output is on, “*” shows beside the output letter. Ex: “V*”.
If the control senses a problem with the output, “*” ashes.
b. “AMPS V_S_F_W_A_” shows in the display. A
checkmark (“
√” ) beside the letter indicates normal amps.
A ashing “X” beside the letter means a problem exists.
c. “NC/GD V_S_F_W_A_” shows in the display. This
monitors a possible problem with the relays on the output
PC board. A checkmark (“√” ) beside the letter indicates
means everything on the output PC board is good. A
ashing “X” beside the letter means a problem exists.
d. V_S_F_W_A_P_E_F_ shows in the display. If the output
or input signal is detected, “*” shows beside the letter. Ex:
“V*”. If the control senses a problem with the output, “*”
ashes.
Press to continue to VENT.
4. VENT
This indicates whether the vent is open or closed.
Press to continue to CPU TMP.
1-5. INFO MODE (Continued)
Feb. 2011
Model AHC-990/993
1-10
1-5. INFO MODE (Continued) 5. CPU TMP
This step shows the present PC board temperature.
Press to continue to the Cabinet Air TMP.
6. CABINET AIR TMP
This step shows the present air temperature inside the cabinet.
Press to continue to the Water Heater TMP.
7. WATER HEATER TMP
This step shows the present water heater temperature.
Press to continue to Food TMP.
8. FOOD TMP
This step shows the present food probe temperature, if used.
Press to continue to Humidity Counts Value.
9. HUMIDITY COUNTS VALUE
Factory use only!
Press to continue to the Humidity Value.
10. HUMIDITY VALUE
This step shows the present humidity level inside the cabinet.
Press to continue to the Water Heater Condition.
11. WATER HEATER CONDITION
This step shows water heater condition as GOOD or BAD.
Press to continue to the Analog Inputs.
12. ANALOG INPUTS
This step displays the present status of any channel of the
controller’s a to d converter. This feature may be useful to a
technician troubleshooting a problem with the controller.
The displayed value can be toggled between volts and bits by
pressing . If the displayed value has a decimal point, it is
voltage (0 to 5 VDC). If no decimal point is shown, value is
a-to-d bits (0 - 4095).
Press and to exit.
Feb. 2011
Model AHC-990/993
2-1
The Tech Mode and Stats Mode in the Level 2 Programming,
have information that could help in troubleshooting a problem
with the unit.
Press and hold until “L-2 LEVEL 2”, followed by,
“CLOCK SET”, shows in display.
Press 3 times and “TECH”, followed by, “ENTER
CODE” shows in display.
Enter code, to access
the following items: (Use hidden buttons, see Section 3-3)
T-1 Software
T-2 Cabinet version
T-3 Push button test
T-4 All on display test
T-5 Segments test
T-6 Digits test
T-7 Decimal points test
T-8 LED test
T-9 Factory Use
T-10 Air temperature - user calibration/offset/highest value
T-11 Factory Use
T-12 Water heater temperature - user calibration/offset/highest
value
T-13 Humidity - circuit calibration
T-14 Humidity sensor – calibration/offset; specic value sent
with each humidity sensor
T-15 Humidity- user calibration/offset/highest value
T-16 CPU° - control temperature - highest value
T-17 Factory Use
T-18 Outputs/Inputs; on outputs steps use the four hidden
buttons [1-4] to toggle on outputs; [1] - vent motor,
[2] - auto ll solenoid valve, [3] - circulation fan,
[4] - water heater, [5] - air heater
T-19 Total init – initialization of programming areas and
statistics
moves you forward through the above selections and
moves you backwards through the selections.
2-2. TECH MODE
SECTION 2. LEVEL 2 PROGRAMMING
2-1. INTRODUCTION
Feb. 2011
Model AHC-990/993
2-2
T-1: Software
This section shows “PN/ID/SRL”
Press and hold the button. The Henny Penny EPROM
part number is displayed.
Press and hold the button. The customer ID (i.e. KFC) is
displayed.
Press and hold the button. The software revision level is
displayed.
T-2: Cabinet Version
This section shows the model number, e.i. AHC-993.
T3: Push Button Test
Press any button on the control and a digital display feedback
conrms the button is working.
T4: All On Display Test
Press any of the product buttons and every LED on the 16 digit
display lights.
T5: Segments Test
Repeatedly pressing any product button lights one segments in
every one of the 16 digit displays.
T6: Digits Test
Repeatedly pressing any product button lights all segments in
one of the 16 digital displays. (Scrolls though all 16.)
T7: Decimal Points Test
Repeatedly pressing any product button lights a decimal point
(DP) in one of the 16 digital displays. (Scrolls though all 16.)
T8: LED’S Test
Repeatedly pressing any product button lights individual
LEDs. (Scrolls though all LEDs.)
T9: Air Temperature - Circuit Calibration
Factory use.
2-2. TECH MODE (Continued)
Feb. 2011
Model AHC-990/993
2-3
T10: Air Temperature - Calibration/Offset/Highest
This is a user calibration to make sure the display shows the
actual air temperature.
Press and hold and use to set the display to
match the actual temperature. (+/-15
o
F)
Press and hold to change the amount of the offset.(+/-15
o
F)
Press and hold to view the highest air temperature recorded.
Press to reset highest temperature.
T11: Water Heater Temperature - Circuit Calibration
Factory use.
T12: Water Heater Temperature - Calibration/Offset/
Highest
This is a user calibration to make sure the display shows the
actual water heater temperature.
Press and hold and use to set the display to
match the actual temperature. (+/-15
o
F)
Press and hold to change the amount of the offset.
(+/-15
o
F)
Press and hold to view the highest air temperature recorded.
Press to reset highest temperature.
T13: Humidity - Circuit Calibration
See Section 3-3 on Humidity Sensor Calibration and
Replacement.
T14: Humidity Sensor - Calibration/Offset
This is a specic value that is sent with the humidity sensor,
when necessary. Otherwise, this value should be 0.
2-2. TECH MODE (Continued)
Feb. 2011
Model AHC-990/993
2-4
2-2. TECH MODE (Continued)
T15: Humidity - Calibration/Offset/Highest
This is a user calibration to make sure the display shows the
actual humidity inside the cabinet.
Press and hold and use to set the display to
match the actual humidity. (0 to 100%)
Press and hold to change the amount of the offset.
(-0 to
-99)
Press and hold to view the highest humidity recorded.
Press to reset highest humidity.
T16: CPU
o
- Control Temperature - Highest Value
Press to show the highest temperature to which the control
board was exposed.
T17: View ADC Channel
Factory use.
T18: Outputs/Inputs
The following components can be tested:
toggles the vent motor off and on.
toggles the ll solenoid valve off and on.
toggles the cooling fan off and on.
toggles the water heater off and on.
toggles the air heaters off and on.
T19: Total Initialization
This completely resets any accumulated information and
changed settings in the controls. Contact Henny Penny before
completing this step.
Feb. 2011
Model AHC-990/993
2-5
2-3. STATS MODE
Press and hold until “L-2 LEVEL 2”, followed by,
“CLOCK SET”, shows in display.
Press 4 times and “STATS”, followed by, “ENTER
CODE” shows in display.
Enter code, to access
the following items: (Use hidden buttons, see Section 3-3.)
ST-1 Power live hours
ST-2 Power ‘on’ hours
ST-3 Power-ups count
ST-4 Errors count
ST-5 Air heat ‘on’ hours
ST-6 Water heater ‘on’ hours
ST-7 Circulation fan ‘on’ hours
ST-8 Water solenoid on hours
ST-9 Solenoid cycle count
ST-10 Longest solenoid on time; max.=5 minutes
ST-11 Vent motor
ST-12 Highest air temperature
ST-13 Highest water heater temperature
ST-14 Factory Use
ST-15 Highest humidity value
ST-16 Highest CPU temperature
ST-17 Water heater (too hot) cycle count
ST-18 Sys ram – fade count
ST-19 Hold ram – fade count
ST-20 Stat ram – fade count
ST-21 Ram data error count
ST-22 Data total loss count
ST-23 User init’s count
ST-24 Auto init’s count
ST-25 Error log
ST-26 Power-up log
ST-27 Factory Use
ST-28 Reset all stats
moves you forward through the above selections and
moves you backwards through the selections.
Feb. 2011
Model AHC-990/993
2-6
2-3. STATS MODE (Continued) ST-1: Power Live Hours
This section shows the number of hours the control has been
on.
ST-2: Power On Hours
This section shows the number of hours the control has been
on.
ST-3: Power Ups Count
This section shows the number of times the control has been
turned on.
ST-4: Errors Count
This section shows the total number of all errors (displayed on
control) that have occurred with the unit.
ST-5: Air Heat On Hours
This section shows the number of hours the air heaters have
been on.
ST-6: Water Heater On Hours
This section shows the number of hours the water heater has
been on.
ST-7: Circulation Fan On Hours
This section shows the number of hours the cooling fan has
been on.
ST-8: Water Solenoid On Hours
Shows the number of hours the solenoid has been on.
ST-9: Solenoid Cycle Count
Shows the number of times the solenoid has been turned on.
ST-10: Longest Solenoid ‘On’ time. Maximum 5 minutes.
Shows the longest the solenoid has been on at any one time, to
a maximum of 5 minutes.
ST-11: Vent Motor On Hours
This section shows the number of hours the vent motor has
been on.
ST -12: Highest Air Temperatur e
This section shows highest air temperature sensed by the tem-
perature probe.
Feb. 2011
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