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14/05/2024

Abnormal Fire. The boiler does not start. Troubleshooting

Greetings! Today our boiler does not start, there is an “Abnormal Fire” signal on the panel, and a “Boiler Total Alarm” on the alarm monitoring system in the ECR. The main switchboard has low insulation 440V, but no alarm.

Abnormal Fire on the boiler
Abnormal Fire on the boiler

There can be many reasons for this problem; in this article we will look at some of them. And we will analyze our case in detail.

Boiler Total Alarm
Boiler Total Alarm

The first thing you should pay attention to is the low insulation of 440V and check the entire power part of the 440 volt boiler. This includes electric motors for auxiliary fuel and feed pumps, a fan, and a heater. In addition, you should pay attention to the distribution cable and terminal boxes.

Power section contactors
Power section contactors
Boiler power section diagram
Boiler power section diagram

Most often, the insulation is reduced in the heater, which “operates” on heavy fuel. The heater operates when the boiler uses heavy fuel.

In this case, the heater insulation really dropped significantly (some elements burned out and showed almost 0 MOhm), the temperature of the fuel in the “glass” dropped to 80°C, despite the fact that the minimum temperature for proper combustion of this fuel should be in the range of 110 - 120°C.

Heater insulation
Heater insulation

We can see the temperature on the controller, which controls the heater contactor.

Heater controller (low temperature)
Heater controller (low temperature)
Heater controller (correct temperature)
Heater controller (correct temperature)

Why didn't the low fuel temperature alarm work? The boiler fuel mode switch was in the DO - FO position. Which means heating the fuel mix to 120°C without a low temperature alarm. So after switching the boiler from diesel to heavy fuel, the toggle switch was not switched to FO.

Heater operating mode switch
Heater operating mode switch

Opening the heater showed that there was a poor flow of fuel in the glass (clogged with asphalt), the heating elements were heated unevenly and gradually burned out.

Asphalt in the heater glass
Asphalt in the heater "glass"
Old heater (remains after removal)
Old heater (remains after removal)
Cleaning the heater "cup"
Cleaning the heater "cup"
Remains of heating elements
Remains of heating elements

At the same time, a thermostat jumper to the final protection of the heater 180°C was also discovered.

Old thermostat after removal
Old thermostat after removal

It is not difficult to conclude that the "glass" began to become almost clogged with tar and the thermostat failed (someone installed a jumper and ordered the new thermostat), but pevious crew did not pay due attention to this.

Heater operation in the circuit
Heater operation in the circuit

As a result, the heater, thermostat, and also the contactor (which was in poor condition) were replaced.

Old heater contactor
Old heater contactor
Old heater contactor
New boiler heater

New boiler heater

The boiler was successfully restarted and all protections were checked. Cleaning the heater and "glass" should be done at least once a year.

Let's return to the "Abnormal Fire" alarm and see what the maker offers in this case.

Abnormal Fire boiler

Abnormal Fire boiler
Abnormal Fire boiler
Total alarm
Total alarm

As can be seen from the diagrams, the “Abnormal Fire” alarm is general and there are no details (even in the instructions) to solve this problem. If the low fuel temperature alarm was turned on, this would suggest the direction of the search.

But despite this, there is monitoring of the operating temperature on the controller, which helps to understand the cause of the “wrong flame” and the failure of the flame in the boiler furnace.

General view of the boiler
General view of the boiler

Boiler model: Miura GK-2230-1400

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