What is causing this problem?Suddenly last night there was a loud knocking noise coming from the box attached to our geo. Have open loop system. System is about 12 years old.
A look at the nameplate would be useful , but looks to be the load side pump. Its a relatively low cost replacement.
Your open loop system has a motorized valve that opens to allow water flow through the unit while operating. Your motorized valve has a valve body, valve cartridge (available in many different sizes and configurations) and an actuator "small black box" Honeywell VC8114. https://customer.honeywell.com/resources/Techlit/TechLitDocuments/95C-00000s/95C-10920.pdf I have no experience with that valve but it has obviously failed. It could be any of the following- -Loose wiring connection or bad electric signal (I assume 24vac) -Failed actuator which consists of a motor, relay, switches and cam -Bad valve cartridge Some one who works with this type and brand valve might be able to diagnose over the Internet. If one is not familiar, it will take some onsite diagnosis to determine what has failed. If you don't mind and can afford "throwing parts at it until it works" (one of my HVAC tech pet peeves) my bet would be replace the actuator.
Looks like I won't be able to find one in town today. It's 90 degrees and the A/C can't keep up. Our geo guys will hopefully be out tomorrow.
Thank you for your time to share your expertise. Our GEO tech finally looked at it today. I wasn't the one who was home, but thought I'd update: I think I understand it was indeed a failed sensor/valve and actuator. Apparently there was lime built up in the valve which broke some plastic gears in the actuator? I don't understand this stuff. This brings me to the question of lime buildup in the main coils. With open loop, that stuff has got to be thick in there after a decade+?? Our original 20 year old propane hot water tank was half full of it... even with using a pre-tank...as we ran without softner. Yet my guys just keep saying they've never had to descale anyone's units. Does anyone have thoughts on lime buildup and efficiency? Is there an easy way to check it out? The guys had no inclination to peek at it, just basically told me not to worry. So, other than suffering from Murphy's law that things must break on the holidays or Friday nights, I'm happy we didn't have to dig up the supply line to the well (the original scare). Now, anxiously awaiting the invoice...
