Hello all.
To be completely transparent, I'm not an HVACR tech. I own a bakery, so I guess I'm usually the customer. So please forgive my ignorance and any guidance is very much appreciated.
We have a walk-in freezer (amerikooler) that's about 20 years old but is a workhorse. Normal setpoint is -10F and it does a pretty good job of staying there year-round although over the last few years it sits at more like 6F in the summer. The unit is located in a non-climate-controlled storage space outside.
Until last week things were good, but then the evap coils started icing up. The only change is that we just hit summer in Texas. Our tech who we trust and who has been servicing this unit for quite a few years came out and said that it was likely the defrost timer/controller (Paragon erc2-151111-303 so it's all combined) was likely the culprit.
He manually de-iced the evap and it got down to 2F overnight. He said charge was fine but we needed a new controller.
Supply chain issues abound but I pulled some strings and got a new ERC2-212111-370 through a personal connection at a parts distributor. This took about three days. In the meantime, the freezer of course started icing up again and here's where I think I messed up. I should have just turned it off/cut the breaker. Unfortunately I was dealing with other issues and didn't realize it had gotten up to 70F inside. An employee noticed and flipped the condenser lock-out switch (the one that connects to the side of the contactor and says "ON OFF") but not the breaker so fans were still running. By the time I got there about 4 hours later the inside of the walk-in was about 98F (hotter than ambient by about 10 degrees).
I turned off the breaker and swapped the controller. (Yes I own a bakery but it's a family business that I took over when Dad passed a couple years ago, my background is in electronics.) My tech knew I was doing this. I set all of the parameters on the new controller according to the factory defaults in the heatcraft manual for a Pro3 with a Paragon controller at low temp -10F. I had also checked the settings of the old controller before removing and they were the same. I triple-checked the wiring and turned it on. Condenser and evap fans spun up, and after a couple minute delay compressor started up. (I assume there's a built-in minimum off time? Would make sense for short power outages.) Sounded no different than before when it was working, overall vibrations felt the same. Inside the unit, it sounded a little more...hissy?
But there's no cooling happening. One thing I noticed was that, when working and at proper temp, I was reading about 4kW at the breaker (I have an energy monitor on most breakers, an Emporia Vue) and now is about 3kW. I also noticed that when it went from working to iced up, the draw steadily decreased over the couple of days down to that level.
My tech is out of town until tomorrow, and will be coming out of course, but I'm just very curious about what could be happening and/or what went wrong. Why would amp draw decrease over time when I would expect that it should increase as the evap coils ice up?
Sorry for the wall of text, and even with that I hope I didn't leave out anything important.
Any explanations or guidance appreciated very much. Thank you in advance.
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