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Subzero 690 fridge freezer. There is about 10 inches of uninsulated suction line leading to the compressor. This frosts up and every few hours defrost
- Thread starter Aalbie
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Cut out for that unit is 1" vacuum. Can you see light thru the condenser, lots of dust in your pic.
Cleaned the condenser its super clean. Replaced the condenser fan last year. I have no idea if the fan inside the freezer is turning on. Was also thinking maybe the wife over packed the freezer with bags and chocked out the airflow. Fridge is 22yrs old but replacement is not an option. Do you think I should lower the pressure to closer to 1-2 or so.
Adding & removing freon is guesswork. To be sure you would have to evacuate, change dryer & recharge. The evap fan is behind the evap which is behind the ice maker. Two switch's up top, left lites, right fan. Again can you see lite thru the condenser(flashlite)
Although I vacuumed the condenser with the flashlight I can see there is still a lot of dust. I cleaned it with a qtip last year. So I’m going to grab a few cans of compressed air. Also confirmed the fan is working in the freezer.
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In all the years I've serviced Sub Zero I have never seen frost back forming enough water to make it down to the floor. In your case I would check the drain trough in the ref section to see if it's over flowing. Not gonna solve the frost back issue but might be the cause of water on the floor. After 22 years that is remarkably clear
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Already checked the drain it’s clear. The ice falls off puddles on top and makes its way down under the fridge.
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I lowered the pressure to 1.5psi and raised the temp from -3 to 0. It still frosts but not enough to melt and puddle. Seems like a Bandaid for now
With a guage hooked up to the freezer I never see the pressure move. It just sits at 1.5. What is the on and off for the fridge? Because the pressure measures 30psi and isn’t moving. Last question. Do you recommend anyone for repair in the Hudson Valley Ulster County NY?
Like I said cutout is 1" vacuum, cut in depends on how long it's been off to equalize. Since you've fooled with adding and removing freon, at this point not knowing if the proper amount is in the system it's impossible to diagnose. If the low side is at 30PSI either the compressor isn't running or if it is it's shot.
harrowgate
Premium Member
Hi, I have this exact same problem on the fridge side, model 642. I've had a tech who thought it was overcharged remove some refrigerant, but still have the problem.
Did you ever figure out what was causing it? Was it a separated cap tube? Any insight would be appreciated!
Did you ever figure out what was causing it? Was it a separated cap tube? Any insight would be appreciated!
He thought? What were his readings? How did it get over charged?
harrowgate
Premium Member
@paulhl you're spot on - I didn't have a chance to be present while he was taking his readings, so I didn't get a chance to record them. He'll be back on Saturday and I'll make sure I get those readings (in all states - with compressor on, off and with cabinet at temp). Tech suspects it got overcharged when the evap/compressor/heat exchanger were replaced several years ago and that tech charged too much, and has just been doing this ever since then -- and water stains in compressor compartment would support this.
Fridge also takes a long time for evap to warm up to the required temp (38f) in off-cycle defrost for compressor to cut in -- cabinet ends up at 45-46f (set for 37) before it comes back on -- could that also reflect overcharge?
After reading this thread, my concern is that it could be a separated cap tube instead of overcharge, but no way to confirm that other than by removing armaflex and inspecting the heat exchanger OR having the tech confirm with pressure/temp readings (which I understand is why you asked your question).
I've asked the tech to remove all refrigerant and then weigh in a new charge, but he's very resistant to doing that. If his next visit doesn't fix it, I'll post the readings he takes, and maybe find someone who will weigh it in properly.
Thanks!
Fridge also takes a long time for evap to warm up to the required temp (38f) in off-cycle defrost for compressor to cut in -- cabinet ends up at 45-46f (set for 37) before it comes back on -- could that also reflect overcharge?
After reading this thread, my concern is that it could be a separated cap tube instead of overcharge, but no way to confirm that other than by removing armaflex and inspecting the heat exchanger OR having the tech confirm with pressure/temp readings (which I understand is why you asked your question).
I've asked the tech to remove all refrigerant and then weigh in a new charge, but he's very resistant to doing that. If his next visit doesn't fix it, I'll post the readings he takes, and maybe find someone who will weigh it in properly.
Thanks!
That 38 temp is the evap temp, not compartment temp. If those items were replaced there should be a small sticker over freon tag with new amount. How much $ is too much. I doubt if cap tube is separated
harrowgate
Premium Member
Understood the 38 temp is the evap temp -- at compressor cut-out, evap temp is 20f, and by the time it comes up to 38f, compartment is at 46f or higher. A new unit costs $15k and is unavailable for 8 months, so I guess anything less than that is do-able. But hoping not to replace entire sealed system on fridge side again, since it was last done in 2017 and those components should still be good.
Don't forget if you are monitoring the temps the door is open and the compartment will rise quicker than the evap. No reason to replace system. your tech has to evacuate system, run a vac pump and recharge with correct amount. With new evap it's different than the sticker says.
harrowgate
Premium Member
Thanks - good to know. (re: monitoring temps, I realize that -- it'll often be at 46-47 in the morning after nobody has opened the door for 10+ hours...)
I'll push my tech to do an evacuation and recharge, or hire one who will. Interesting about the sticker -- the door tag still has the original amounts on it, they haven't been stickered over. This unit was R134a from new and hasn't been converted from R12 -- would the proper charge still be different for a new evap?
If so, most of them that I've seen with stickers have a HIGHER charge called for on the sticker than original -- maybe the tech who replaced evap got confused and charged with higher amount but should have charged with amount on original tag?
In any event, only 1 way to find out
Thanks for all your help.
I'll push my tech to do an evacuation and recharge, or hire one who will. Interesting about the sticker -- the door tag still has the original amounts on it, they haven't been stickered over. This unit was R134a from new and hasn't been converted from R12 -- would the proper charge still be different for a new evap?
If so, most of them that I've seen with stickers have a HIGHER charge called for on the sticker than original -- maybe the tech who replaced evap got confused and charged with higher amount but should have charged with amount on original tag?
In any event, only 1 way to find out
Thanks for all your help.SZ doesn't convert, no reason to. All 600 series are 134A. The newer style replacement evaps usually have less than original amount on the 600 series and the same or a little more on the 500 series. It varies with each model.
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