Post a reply to the thread: High pressure trip w/ low charge
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Originally Posted by Dallas Duster You do what ever you want to it It's the customers machine and he can pay you to make any modifications to it that he wants. For all I care you can put a TXV on it and go with it. Yeah, it'll be a good learning experience!!!
Carrene #2 you made the most sense. I figured a plugged drier but couldn't figure high pressure trips. I also assumed a pressure switch not a DDC controller. I am not familiar with the equpment being described. Was this an actual pressure switch shutting the comp down or a program in the controller? What brand?
You do what ever you want to it It's the customers machine and he can pay you to make any modifications to it that he wants. For all I care you can put a TXV on it and go with it. Originally Posted by KB Cool Ok i'll keep that in mine if i have to go back!! I figured i couldn't go wrong by following the manual's charging instructions!
Ok i'll keep that in mine if i have to go back!! I figured i couldn't go wrong by following the manual's charging instructions!
Originally Posted by KB Cool Come on! Who's to say my thermocoupler aint off by 2 degrees!!! With the microchannel coils I pretty much always go to the low side, and I don't think 15-17 degrees SC is correct for the microchannel unit, I may be wrong but I don't think so. Sounds right for the standard copper/aluminum coils though. If you haven't seen just what the MC coils look like, you really need to take a look. What you have is pretty much a 1"x 1/8" flat piece of aluminum with say 10 to 15 capillary tubes running the length of the aluminum bar. They don't hold very much refrigerant in them. It is very easy to trip the HP switch with even a slight overcharge. ...Ron
Originally Posted by Carrene #2 Damn, I swore to myself that I was done with this. I'm weak. Do the words "critical charge" ring a bell? Best of Luck : Dick Come on! Who's to say my thermocoupler aint off by 2 degrees!!!
Originally Posted by KB Cool Why? IOM says 15°-17°. I figured 1 degree over aint gonna matter. Damn, I swore to myself that I was done with this. I'm weak. Do the words "critical charge" ring a bell? Best of Luck : Dick
The digital scroll is actually a cool device. It allows a greater range of capacity control than traditional unloaders on a recip. It is designed to load / unload frequently to deliver a specific output. 40% load time = 40% capacity. Better load matching. Most units are sized for peak load and run there a small percentage of time. So you have an oversized 10 ton scroll cycling on and off. Over and over. Hard on the compressor for sure. This compressor can stay running and stay healthy. Oil management with these is a whole different topic.
Originally Posted by rscamaro Too much subcooling for a 410a unit with microchannel coils. ...Ron Why? IOM says 15°-17°. I figured 1 degree over aint gonna matter.
Sometimes EEV controls condenser fans. This could do it.
Originally Posted by KB Cool Yeah i blocked off the condensor to 120° CST and gave it 18° SC. Too much subcooling for a 410a unit with microchannel coils. ...Ron
Originally Posted by Dallas Duster I guess the boss wins over common sense what is there a whopping 9 pounds or refrigerant in that machine. 8.6 lbs. There's about eleven in it now!!!!
I guess the boss wins over common sense what is there a whopping 9 pounds or refrigerant in that machine. Originally Posted by KB Cool I know i didn't want to add the dryer. Would have been much easier just to go back in w/ the 165s. But, my Boss talked the owner into doing the replacable core as thier maintenace men will be able to replace it on the fly as needed!!!
Originally Posted by Carrene #2 Thanks, but no thanks. What a D!ck!!! Nah, he aint a bad guy afterall!! Thanks for the 33% tip Carrene. Well definetly look into it if this compressor decides to lock up!!!
Originally Posted by Dallas Duster He might be ok charging it up now since he added a small receiver to the system. I know i didn't want to add the dryer. Would have been much easier just to go back in w/ the 165s. But, my Boss talked the owner into doing the replacable core as thier maintenace men will be able to replace it on the fly as needed!!!
Originally Posted by chilbrig With the Micro coils the head will spike at startup then come back down to normal operating conditions. On a hot day it should not spike much over five hundred psig. If you must weigh in the charge subtact about five percent of what it says on the tag. If you overcharge just a little, it will trip. There should be a charging procedure in the OM book, that is the best way to charge it up. Again, if you have any restriction in the drier you will have problems. Yeah i blocked off the condensor to 120° CST and gave it 18° SC.
He might be ok charging it up now since he added a small receiver to the system. Originally Posted by chilbrig With the Micro coils the head will spike at startup then come back down to normal operating conditions. On a hot day it should not spike much over five hundred psig. If you must weigh in the charge subtact about five percent of what it says on the tag. If you overcharge just a little, it will trip. There should be a charging procedure in the OM book, that is the best way to charge it up. Again, if you have any restriction in the drier you will have problems.
With the Micro coils the head will spike at startup then come back down to normal operating conditions. On a hot day it should not spike much over five hundred psig. If you must weigh in the charge subtact about five percent of what it says on the tag. If you overcharge just a little, it will trip. There should be a charging procedure in the OM book, that is the best way to charge it up. Again, if you have any restriction in the drier you will have problems.
Originally Posted by KB Cool Well, the customer knew they could not possibly run a 10 ten system on 1" pipe. But, they did think the unit was a true varible speed "digital" scroll and it would be ok ! Serious!!! P.S. I just saw your edit a little bit ago!! I'll tell them to call you next time!! Thanks, but no thanks.
Originally Posted by Carrene #2 Just got one like that! Misapplied! Well, the customer knew they could not possibly run a 10 ten system on 1" pipe. But, they did think the unit was a true varible speed "digital" scroll and it would be ok ! Serious!!! P.S. I just saw your edit a little bit ago!! I'll tell them to call you next time!!
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