Reachin produce cooler problems
I have a reachin produce cooler that is shutting down. The high pressure control is shutting the compressor down. Here are the symptoms. The cooler is a r404 unit. It was 95 dg. Ambient.
High head pressure, should be 330 but was reading 380
High low pressure, should be 50 but was reading 68
High superheat, it was 20 dg to high
Low sub cooling, about 2 dg low.
The cooler should be around 38 dg but it keeps shutting down and warming up.
I'm thinking that there is air or non condensables in the system. I'm thinking I should recover the refrigerant, evacuate and change change the filter drier. Then recharge with virgin refrigerant.
Any opinions would help.
I hate to ask, but have you cleaned the condenser. Even if it looks ok from the outside, it still may be dirty. Also, what kind of expansion devise, tev or cap tube?
It has a tev valve. And yes iv cleaned the condenser. It's a older unit. It's been retrofitted to r404. And I forgot to mention it has a lot of bubbles in the sight glass. Almost looks like the refrigerant is boiling. There that much bubbles. Thanks for your reply.
You need more 404a. Add until u have no more bubbles.
Where is your high side gauge manifold hose connected, liquid line, discharge line?
If you have a restriction upstream from the sight glass, it will flash.
Possible you have a restriction - plugged drier or other restriction. If it was retrofitted to 404a, the oil may have been changed to polyol ester. Polyol ester oil acts like a detergent, so if there was any crap in the system it will loosen it up and plug driers and cause other problems. Could be non-condensables as well.
Is there a noticeable temperature drop across the drier right now?
I think you're on par, pull charge, change drier, blow out system with nitrogen to ensure no other restrictions. Pull a good vacuum and weigh in the correct charge (if applicable).
Another thing too, I see your post count is 49. If you haven't already, apply for pro membership. We can get into a better technical discussion in the pro forum.
My high side is connected to the receiver. If its low on refrigerant the pressures should be low, right? So I don't think it's low. I really think its a restriction of sorts. Thanks for the help.
What is the control set for? If it's set for 380, it's set too low. I'm also not understanding how you are determining what the pressures "should" be, unless you are familiar with this unit and if that's the case, how did the non condensables get inside? Also, the SH being 20* too high. Where are you checking your SH at? If it's not at the coil, it doesn't really matter as there are a number of other reasons the SH at the pump could be high. Does the unit have a headmaster?
Officially, Down for the count
YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET
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You aren't getting rid of the heat. Airflow, dirty coil. No restriction since the subcooling isn't high. No air in the system for the same reason.
Originally Posted by bigbucks
Post actual temps. Gives a better picture.
Out of curiosity. What are you looking for, for subcooling and superheat? Where are you measuring both?
If you suspect non condensables, pump the unit down......if you can....if you can't pump down then shut the king valve and then shut off the unit. Disconnect the compressor and allow the condenser fan to run for half an hour. Measure your ambient temp and check it against your hi side pressure. If they don't match you have crap gas.
is there a shroud on the fan ?? I bet not
I've made my own shrouds from those cheap alum foil pans they have in most kitchens .... with layers of foil tape and zip ties
Or plexi glass if you really want to get fancy
Or you can be a sissy and order one from manufacturer
If it does have a shroud already , might need a bigger pitch blade
Low subcooling almost rules out non condensibles.
You'll tend to see higher subcooling with non condensibles in the system.
Clean the condenser, check the condenser fans, etc.
with this being a retro fit ..... he may need to retro some other stuff , like a fan blade that pulls little more air , possibly motor too