Weil-McLain Aqua Balance WMB-155 Manual page 88

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AquaBalance
34 Troubleshooting
Make sure to determine the causes of outages. Do not leave the boiler operating without a com-
plete diagnosis.
Control diagnosis
1. The boiler control is equipped with an advanced self-diagnosis system. In case of a boiler fault, the display will flash together with
the fault symbol (see Table 3 or Table 4) indicating the fault code.
2. Certain faults cause permanent boiler shutdowns (marked with the letter "A" see Table 3): to restore operation, press the RESET
button (Item 6 - Figure 76, page 60) for 1 second or RESET on the optional remote timer control if installed; if the boiler fails
to start, it is necessary to firstly eliminate the fault.
3. Other faults (indicated with the letter "F", see Table 4, page 91) cause temporary shutdowns that are automatically reset as soon
as the value returns within the boiler's normal operating range.
Protection and error conditions
1. Several checks are included to protect the boiler and its environment. Severe error will cause a lockout condition which can only
be cleared by the reset key at the boiler front panel.
2. Non severe errors faults will reset as soon as the cause of the problem disappears/corrects themselves.
3. Number of reset action is limited to 5 in 24 hours. By powering off/on, it is possible to reset this limitation: in this way, another
5 reset per 24 hour can be done.
4. Error codes can be divided in 2 groups:
a. Lock-out condition codes – "A" codes: (which blocks the heat demand - Press reset button for 1 second to reset)
b. Blocking condition codes – "F" codes: (cause temporary shutdowns that are automatically reset as soon as the value returns
Lock out condition codes
Lock out condition is given with the capital "A" (alarm) on the status display and error code on the
temperature display. The meaning of the error numbers are as follow:
Table 3
"A" codes
Error code Description
A01 Lockout indication
A02 )DOVH ÀDPH LQGLFDWLRQ
High limit protection: pump does not run or no
A03
water circulation
A04 F07 repeated 3 times in the last 24 hours
A05 No frequency feedback from fan after 1 hour
A06  WLPHV ÀDPH ORVV LQ  PLQXWHV WLPH IUDPH
A16 Outside sensor is not connected
Nominal water pressure not reached within
A23
maximum allowed time
A24 0RUH WKDQ  ZDWHU ¿OOLQJV LQ  KRXUV
A26 F40 repeated 3 times in the last hour
Temperature sensor not or bad connected to
A41
the pipe (CH mode)
Too high difference between two CH supply water
A42
temperature sensors
Temperature sensor not or bad connected to
A44
the pipe (DHW mode)
A61 Flame circuit error
A62 Gas valve circuit
A63 E2 prom error
A65 ADC circuit error
88
M -
ALL OUNT GAS FIRED WATER BOILER
(continued)
within the boilers normal working range)
—
Boiler Manual
Abbreviation Description
ADC Analog Digital Converter
CH Central Heating
DHW Domestic Hot Water
LP /LTXH¿HG 3HWUROHXP 3URSDQH *DV
LWCO Low Water Cut Off
MMI Machine Interface- Control Interface
OTC Outdoor Temperature Sensor
PCB Printed Circuit Board - Control board
Pulse width modulation - Used for
PWM
modulating pumps and motors
Part number 550-100-305/0118