Ravelli RV80 - Problem: Air Flow Meter

[DaveInMaine]

Thanks for the info on the thermistor. I had narrowed it down to a Panasonic one that I thought should work, but I went with the one you used, since that one now has a proven track record. I had measured the resistance of one of the working old ones at room temperature, and again when sitting on an ice cube, in order to get an idea of the response range I should be looking for. But tried and true is always better than a guess, so thanks again for the point in the right direction.

 

[DaveInMaine]

Update - The repaired component has been working well for the past few weeks. I wanted to mention a theory I had as to a possible cause of the frequent failure of the airflow sensor. When removing the bad thermistors, I noticed that the thin metal ends of the tiny thermistors seemed to separate from the main body of the part very easily. On one of the failed units, one of the thermistors was completely missing upon removal from the stove. Under magnification, there appeared to be some corrosion on the remaining solder on the board. I also noticed that the failures (at least on mine) always happened over summer. The stove would work great all winter, then when starting it for the fist time the following fall, it would get the airflow sensor error.

So my theory is that perhaps over the summer, when it is hot and humid outside (and nice and cool inside the air conditioned home), the moist air outside could blow in though the outside air intake on windy days, and condense inside the cooler intake pipe - where the sensor is, leaving the sensor moist with condensation. This could eventually lead to corrosion of the connections on the delicate parts by fall. So, I am thinking it might help to cover (or disconnect) the outside air intake over the summer to prevent possible condensation issues. It's just a guess, but it can't hurt to try it if you are also experiencing frequent airflow sensor failures every year. Maybe it will help them last longer.

 

[Pelleting In NJ]

Interesting theory, but I would not expect the metal ends, or the solder, to corrode from moisture.

Are you saying that one of the thermistors was completely missing from the board?

Do you have any pictures?

One of the failed airflow meters I got from Manly, had evidence of high temperature damage (browning of the edge of the board finger that faces the firebox), which I concluded happened when there was a strong wind induced backdraft, that could force hot exhaust gases from the firebox to flow backwards thru the intake air pipe, past the airflow meter, cooking it a bit.