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Brivis ME20e flame continues to be lost

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  1. #1
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    Default Brivis ME20e flame continues to be lost

    Hi all
    I've been struggling with fixing my heater for about a week now. Brivis seem to be too busy and they wont come out for another 11 days.
    The best way to described my problem is through the attached flow chart I got the Brivis service manual. When the controller (Brivis calls it the networker) calls for heat, the combustion fan would start and the system will go through a pre-purging phase, follow by the ignitor (HSI) turning red, and with the gas value energized, the burner is lit up and the flame turns blue when HSI is powered down, the flue fan will slowly reduces speed, the flame usually goes out during the flaming proving stage. Occasionally it will go past that but the flame still goes out. The flame is never on for more than 30 seconds.
    I have replaced the flame sensors, cleaned the burner, but it didnt fix the problem. Most of the error codes are 65 lock out, when there are too many flame loss. I've checked the thermistor, it is 18Kohms. The manual says it should be 10. And when I red the info page from the lo module, it shows the the supply air thermistor is 70 - 80 degrees when the network is not calling for heat. Should the thermistor be showing room temperature instead. I am not sure if the thermistor is the cause of the flame loss. According the flow chart, the flame is lost even before the thermistor is calling for heat. Could it be the problem with the gas control value? How do you test that the gas value is faulty (It costs over $300)
    Any ideas welcome
    Cheers
    Paul.
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  2. #2
    2K Club Member chrisp's Avatar
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    Have a read of this thread for some possible tips: http://www.renovateforum.com/f193/br...g-issue-97868/ - particularly post #13
    There is no middle ground between facts and fallacies - argumentum ad temperantiam

  3. #3
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    Having just read that old thread Chrisp, they are a shocking heater to work on, and you really need to be Brivis trained in those heaters to fault find.

  4. #4
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    Hi,
    Thanks plum and Chrisp for your replies. I have read through the thread carefully and have checked the black rubber hose and can confirm it was fine. I have eventually rectified the problem and would like to share with others who might have the same problem.
    Not long after I posted last. I was getting an Thermistor overheat message on the lo module as soon as I powered up. This had also forced the fan into a permanent purge mode trying to cool down the overheating in the duct that wasn't there and it was a reasonable explanation why I couldn't switch off the heater fan from the controller.
    So I was pretty confident I had to replace the thermistor. I had a choice of crawling under the floor on my belly with a shuffle and dig myself a tunnel to get to the thermistor or accept the service of a ex brivis technician who happened to be around my neighbourhood in the next day or so. Without much hesitation. I accepted the latter.
    He confirmed that the thermistor was faulty but also said that was a separate problem from the the flame going out and solenoid value shutting down the gas supply. To bypass the thermistor problem, He took out the thermistor connection from the hi module. (Anybody who attempts this must first turn off the power supply to the heater unit). When I turned on the heater, the controller complained that the thermistor has an open circuit, you can override the message by pressing one of the buttons on the networker. Bypassing the thermistor problem, the controller called for heat, and combuston fan swung into action. Like I mentioned in the first post, the flame ran out and the solenoid value shut down the gas supply. We noticed that the flame near the backup flame sensor went out first, without sensing any flame, the lo module shut down the gas supply completely. Eventually, the solution was reasonably simple. The tech adjusted the gas amplification module, that is the module that has the rubber hose and aluminium tube connected to it (see attached picture). Its main function is to continuously adjust the gas supply pressure delivered to the burner based on the pressure drop across the orifice in the combustion air supply, so whenever more heat is called for, the lo module increases the speed of the flue fan and the gas supply to the burner is automatically increased by the amplifier. Adjustment can be made once the aluminium cover screw is removed. Do not adjust the screw by more than 1/8 of a turn each time because it rarely needs more than a minute adjustment. A word of warning, over adjusting the amplifier could make it un-serviceable. Also, it is possible to make the gas mixture too rich which would lead to incomplete combustion and carbon monoxide being emitted. The colour of a complete combustion should always be very light blue. It is also advisable to have a CO meter. I didnt have one, but the tech had.
    The tech also put a new thermistor in the ductwork by sticking his arm as far into the ductwork as possible after prising open the heater supply air flanged cover. It was much easier than I would have approached it.
    Thats all that was needed. I hope this is useful for someone who has a similar problem.
    Attached Thumbnails Attached Thumbnails brivis.jpg  

  5. #5
    Slow but rough Uncle Bob's Avatar
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    Thanks for posting back the resolution, others may find it very helpful

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