60
MCP15-500.9
Display
Code
Description
Additional comments and notes
888
Board Failure
(Up to 10 sec @ power up)
Verify 24 VAC signal input at connector J6.
Off
UP Mode: Burner state = Off
Normal Operation
Pur
UP Mode: Burner state = Purge
Ign
UP Mode: Burner state = Ignition
HEA
UP Mode: Burner state = Warmup
Run
UP Mode: Burner state = Run
rEt
UP Mode: Burner state = Retry
(with
A01
or
A02
)
Retry delay following either a failed ignition or a flame loss.
A01
Failed ignition attempt
A02
Lost Flame
Ignition was successful but then flame disappeared.
A03
Insufficient Combustion Air
Blocked vent with actuator position de-rated by >20% from FRI setting.
A04
Limited Low Fire
(due to Lost Flame Auto-Adaptation)
Flame loss at low fire results in an auto-adjustment limit of the burner turndown
by adjusting the minimum modulation voltage during the rest of the current
cycle or until a CPU reset.
A05
Weak Flame Signal
Flame presence signal of less than 1.5μA indicates an aged flame rod.
A06
No Low Fire Mode
(due to Hi Gas Pressure at Low Fire)
The Gas Pressure is not modulating down to low fire.
A07
Loss of Inducer Motor Control
The Air Pressure is not modulating down at minimum inducer drive.
A08
Air Sensor Null Pressure Check out-of-tolerance
The Air Pressure sensor zero reading appears to be out-of-tolerance.
A99
COM Error – Secondary Furnace(s)
CRC errors, serial bus loaded down or possibly poor cable/routing.
E01
Failed Ignition
Four failed ignition attempts have occurred.
E02
Primary Limit Failure
Verify Primary Limit input at connector J8 and fuse at F1.
E03
Modulation Valve Failure
The Valve Actuator did not reach a Park or Full On position.
E04
Air Sensor Failure -
Pressure Reading Low
Includes air switch failure to open during pre-purge switch check, includes
insufficient air lockout due to blocked vent.
E05
Air Sensor Failure -
Pressure Reading High
Includes air switch failure to close during pre-purge switch check.
E06
Gas Sensor Failure -
Pressure Reading Low
(Possible modulating valve actuator misalignment)
Verify Gas Pressure Sensor signal input at connector J13.
E07
Gas Sensor Failure -
Pressure Reading High
(Possible modulating valve actuator misalignment)
Significant Gas Pressure detected during the Off burner state.
E08
Improper Flame
E09
No Firing Rate Input
The thermostat “W” input is calling for heat but the FRI is < 2.0 V.
A20
Secondary Furnace A COM Missing
Loss of a previously established serial communication link.
A21
Secondary Furnace A Lockout
Refer to VB1201 secondary board diagnostics table.
A30
Secondary Furnace B COM Missing
Loss of a previously established serial communication link.
A31
Secondary Furnace B Lockout
Refer to VB1201 secondary board diagnostics table.
A40
Secondary Furnace C COM Missing
Loss of a previously established serial communication link.
A41
Secondary Furnace C Lockout
Refer to VB1201 secondary board diagnostics table.
Eid
Invalid I.D. Plug Installed
Table 60.1 - Primary Furnace Control Board (VB1200) Error Codes
(Applies to B-, C-, and D-Cabinet Units with Gas Heat Option furnace model number Digit 11=6 or 8)
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SERVICE & TROUBLESHOOTING - CONTINUED
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To clear furnace control board error codes, refer to the section “Clearing Furnace Control Board Error Codes” on page 25.