Any refrigeration guys here?
- Thread starter Redmt
- Start date
Redmt
Well-known member
The whole HVAC is smoke and magic. It talks about super heat and stuff that will remain a mystery to me.
Wait!! I think there's a knob on the other side of the cooling fan. I never messed with it because it runs all the time around 12* or so when it was cooling better.
Redmt
Well-known member
It still ran all the time when it would get down to 10-12*. It would have been nice if it would cycle at temperature instead of running 24/7. Now that the temperature jumped up, it's definitely running all the time. I'm fortunate the amp consumption is low on the 120v compressor
Redmt
Well-known member
I may be dumb but I ain't stupid. There's no way I would bet you but I would go for a shot or two.
Can it have a low charge and not have bubbles in the sight glass? Like I said I have gauges but have no idea what the pressures should read. I just charged it until the bubbles went away then bled it of through the Schrader valve a bit at a time over a couple days until I got an occasional bubble.
Can it have a low charge and not have bubbles in the sight glass? Like I said I have gauges but have no idea what the pressures should read. I just charged it until the bubbles went away then bled it of through the Schrader valve a bit at a time over a couple days until I got an occasional bubble.
The sight glass is a very unreliable way of determining charge, unfortunately. Pressure gauges are the only sure bet. Suction should read around 20 pounds, discharge should read around 250. There's a bit of margin of error there, but that's the ball park.
Redmt
Well-known member
I'm going to check the pressure before I do anything tomorrow.
I used the bubble thing because when you don't know, you don't know. Someone said that a long time ago and it sounded reasonable to me!
I used the bubble thing because when you don't know, you don't know. Someone said that a long time ago and it sounded reasonable to me!
Redmt
Well-known member
I can't thank you enough. I've been fiddling with this box for years. I have a walk-in cooler and it's been flawless forever. I bought both the boxes years ago used and completely disassembled. I'm pretty happy with them but the freezer has never been correct. I had a guy a few years ago that was going to check the freezer out but he wanted $1000.00 travel time. If he didn't have something he needed then he would charge me another $1000.00 to come back. I passed on that one.
Redmt
Well-known member
I have always tried to charge people by how I would want to be charged if the table was turned.
warmer
Well-known member
Rule #1- take everything an engineer says with a grain of salt. Guys with 40 years of experience and no degree are much more reliable.
Redmt
Well-known member
I checked pressure this morning.
The valve at high pressure side was stuck, maybe not stuck but couldn't get it open in the tight area. I took reading at output side of what I'm guessing is an accumulator. It was 185#. The low-pressure at the manifold was maybe 18. I lost a BUNCH of Freon disconnecting the high pressure hose probably to the 160# range. The sight glass appeared to be empty. I'm adding 404 to the low side working to get it stabilized at 20#. I'm ordering another cylinder of 404 today.
The capillary tube goes from the low pressure manifold to the pressure switch.
Should I clear the ice off of the expansion valve?
The valve at high pressure side was stuck, maybe not stuck but couldn't get it open in the tight area. I took reading at output side of what I'm guessing is an accumulator. It was 185#. The low-pressure at the manifold was maybe 18. I lost a BUNCH of Freon disconnecting the high pressure hose probably to the 160# range. The sight glass appeared to be empty. I'm adding 404 to the low side working to get it stabilized at 20#. I'm ordering another cylinder of 404 today.
The capillary tube goes from the low pressure manifold to the pressure switch.
Should I clear the ice off of the expansion valve?
Yes, clear the ice off of the expansion valve.
When adding the 404, add a little at a time and let the expansion valve have a chance to react to the freon coming in. The sight glass will often look "full" when adding freon, even in small amounts for a couple of minutes after it's added. So add some, wait a few minutes, add some more, wait a few minutes, etc. Once you get to the point where you've waited a few minutes and there's no longer any bubbles, it should be pretty full. It also depends on what the maximum charge is, there can be some variance there.
Edit: If possible, take the high side reading from the discharge valve. Sometimes it's hard to get open, but it's a good place to take the measurement.
Redmt
Well-known member
I followed the procedure you laid out. I charged it very slowly and let it equalize each time I gave it a little. I gave it a 5 count on gauges valve open each time until the bubbles were gone. It's holding at 18* now.
I ordered a cylinder of 404a , a new suction side valve as well as a wrench to get a little bit more leverage on the high side valve at the compressor. With having a full cylinder of 404 I can be a little braver messing with the high side valve.
When I first checked it this morning the high side was only 185 PSI. What would cause the lower pressure?
Bigjay73
Well-known member
I've worked on everything from reach ins to ammonia systems, barely rarely have I seen a problem with a suction valve, other than leaking. You need way more info to figure out what is going on. Is there a receiver? What is you superheat at the coil? At the compressor? Coils free of ice? Frost is typically normal, ice on coils is definitely a problem. Ice between a TXV and coil isn't an issue, anything past the TXV that isn't in the airstream will Frost or freeze. Did you check for a temp drop across the drier? Take line temps and we can get you an answer. And use a clamp on sensor, nothing else will be accurate
Redmt
Well-known member
The suction valve is rusted so that it is stuck.
I don't know what a receiver is unless it's the cylinder between the cooling "radiator" and the sight glass on the high pressure side. I don't know how or have the equipment for checking temperatures unless my infrared gun for checking diesel exhaust temperature would work. I doubt it would be very accurate in an open atmosphere
I don't know what a receiver is unless it's the cylinder between the cooling "radiator" and the sight glass on the high pressure side. I don't know how or have the equipment for checking temperatures unless my infrared gun for checking diesel exhaust temperature would work. I doubt it would be very accurate in an open atmosphere
@Bigjay73 is spot on.
If you have a restricted drier, that will cause a temperature difference between inlet and outlet.
The temperature gun works in a pinch but isn't the best method - bigjay is right that clamp on sensor is the best method.
Edit: And that cylinder you were talking about is the receiver, yes.
If you have a restricted drier, that will cause a temperature difference between inlet and outlet.
The temperature gun works in a pinch but isn't the best method - bigjay is right that clamp on sensor is the best method.
Edit: And that cylinder you were talking about is the receiver, yes.
Redmt
Well-known member
Receiver?
