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B&G Series 100 randomly shuts off?
Hello, been a regular browser here for some time, great site. And now finally i would love the help of some people if they could.
I bought my home almost 4 years from a union pipe fitter so needless to say this homes heating system is extremely complex and very overbuilt. I have radiant floor heat, baseboard radiators, an oil boiler (Viessmann), an outdoor wood boiler (Greenwood Aspen, heavily modified), Aos roof mounted hydronic panels, 3 hot water tanks and all sorts of commercial grade expansion tanks, pumps, heat exchangers, etc. I don't even understand. I had a residential heating guy come out here to look at my system so i could have a better understanding of it and he gave up and told me to call a commercial level tech.
Than being said, my current issue is on my outdoor wood boiler. Mounted at the boiler is a B&G series 100 bronze circulator pump that pumps the water from the boiler to the heat exchanger in my garage and then back to the boiler. I have used my wood boiler every winter with zero issues until last year. Within a few days of starting up the boiler for the year last winter the water was not getting very hot at the heat exchanger despite the temp at the boiler being 180. This was never an issue in the past. Then the boiler started boiling over and dumping water out the top (open system) very often. I noticed the circulator pump was turning on and off randomly. Which certainly explains why i was having the issues. The boiler was overheating because when the pump would stop the boiler had no way to get rid of the excess heat. Then the pump would kick on the boiler would cool down enough and id have heat and things would be fine. Then it would happen again. This was happening multiple times a day. I finally shut the system down until now when i finally have time to hopefully fix it.
My outdoor boiler has one power circuit. When the breaker is switched on the circulator pump runs continuously and the electronic boiler temp control is on. The only thing the temp control does is turn the fan for the firebox on and off. Their is no Aquastat on the pump. Its directly wired to AC. The pump always ran 24/7. I removed the pump yesterday and used a Supco motor tester and it instantly failed the test. The pump looks to be at least 25+years old. So i'm not surprised. But when i wired the pump on my workbench it kicks on and seems to run fine (granted, not under any load) and its quiet. I could pretty easily spin the pump shaft on the bearing housing on the boiler. So i know that's not seized.
So all of the above being said, the simple question is.... Would a B&G pump randomly turn on and off despite having power constantly applied? Even when the pump was not running the boiler control was still on. So i know their was power there. Is their some sort of thermal overload inside the pump motor? Could the pump perhaps be seizing up and then un-seizing itself despite not doing enough damage to itself to allow it to still work on my bench test?
Any help from you experts would be appreciated. I searched every source i could find about these pumps and have not seen anyone talking about this issue. Thanks!