I have a 3-ton scroll split system with the condensing unit on the ground and evap in the (hot) attic. In my climate, this unit sits idle for 9+ months, so the 1st start is always flooded, since the condensing unit is colder than the evaporator (and lower, if gravity has anything to do with it). The compressor noise on that 1st startup is painful to hear! Today I installed a soft starter and it's amazing how well that works! The unit hadn't run since last September (July today), and 1st startup sound had none of the previous clattering noise as was normal after sitting for so long. I didn't expect this to work as well as it does. Yes, the "correct" way to combat this would be a crankcase heater (or bump starter as I learned from you today), but it's hard to justify expending all that power for the heater when the unit sits idle for so much of the year.
If you have a liquid line valve, you can close it, run the system to lower the LP side presure to just a little bit above the atmospheric pressure (to prevent air infiltration in the system), and put an electical protection to prevent anyone else to run it. When needed for the hot season, you just have to reopen de valve and run it normally (sort of a manual pump down).
I attended Trevor Matthews for a week compressor class it was worth every penny. As I was attending class I was just going through one of my jobsite locations that on one system the previous technician burnt out for compressors. And I’m just following all the procedures that are in the manual to prevent a reoccurrence.
Thank you T lech! If anyone is interested at learning more about Refrigeration Mentor paid and free training events like t lech attended go the the events pages at refrigerationmentor.com
Great video. I replaced a grounded 3D semi 10 hp on a boat the other day. It had a 7/8 hot gas bypass solonoid on the discharge to suction before accumlator. It was controlled by a bypass timer and set for 10 seconds upon startup. I found out the old bypass timer was getting stuck some cycles. I replaced the timer. I wonder if someone installed this at sometime to prevent flooded start? Not really sure.
What of liquid at SH's below 20F for extended period of time at the compressor the oil droplets displacing oil on the internal surfaces causing friction points, thus scoring & eventually failure.
Great question. It all depends on the refrigerant. Some can run at lower superheats so cannot. Always check the compressor manufactures superheat tolerances.
So I dumbly charged the unit r22 thru the suction as a liquid before I started the compressor up. I’m thinking that i flooded the compressor because it turned on for 5 seconds then tripped the breaker. Would I have to wait for the gas to turn into vapor as it’s been 2 days since I’ve started it, or should I reclaim some of the refrigerant from the suction side?
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It’s amazing how much insight can be packed into a short, 14 minute video.
Thank you Kyle
I have a 3-ton scroll split system with the condensing unit on the ground and evap in the (hot) attic. In my climate, this unit sits idle for 9+ months, so the 1st start is always flooded, since the condensing unit is colder than the evaporator (and lower, if gravity has anything to do with it). The compressor noise on that 1st startup is painful to hear! Today I installed a soft starter and it's amazing how well that works! The unit hadn't run since last September (July today), and 1st startup sound had none of the previous clattering noise as was normal after sitting for so long. I didn't expect this to work as well as it does.
Yes, the "correct" way to combat this would be a crankcase heater (or bump starter as I learned from you today), but it's hard to justify expending all that power for the heater when the unit sits idle for so much of the year.
Put the CCH on a switch or a time delay relay and turn it on 24 hours before you start it.
If you have a liquid line valve, you can close it, run the system to lower the LP side presure to just a little bit above the atmospheric pressure (to prevent air infiltration in the system), and put an electical protection to prevent anyone else to run it. When needed for the hot season, you just have to reopen de valve and run it normally (sort of a manual pump down).
Thank you for the great effort in making this training.
Glad you enjoy it!
I attended Trevor Matthews for a week compressor class it was worth every penny.
As I was attending class I was just going through one of my jobsite locations that on one system the previous technician burnt out for compressors. And I’m just following all the procedures that are in the manual to prevent a reoccurrence.
Thank you T lech! If anyone is interested at learning more about Refrigeration Mentor paid and free training events like t lech attended go the the events pages at refrigerationmentor.com
Thank you trevor I had been following your trainings. they are very informative
Thanks!
Excelent Video. You hit all key points. Congratulation!
Thank you for commenting. We have many more great things from Refrigeration Mentor here linktr.ee/refrigerationmentor
Great info as always Trevor. You are the best!
Robert thank you! Keep up the learning.
Thank u, Trevor.
Your welcome
Thank you for sharing your knowledge
You are welcome. Please share with others.
Another great video! Keep em coming
Thank you. Will do.
Great video. I replaced a grounded 3D semi 10 hp on a boat the other day. It had a 7/8 hot gas bypass solonoid on the discharge to suction before accumlator. It was controlled by a bypass timer and set for 10 seconds upon startup. I found out the old bypass timer was getting stuck some cycles. I replaced the timer. I wonder if someone installed this at sometime to prevent flooded start? Not really sure.
To reduce the amount of inrush current to start up I would assume.
Thank you Trevor!
My pleasure!
Thanks Trevor!
My pleasure!
Great content. Why is it that manufacturers don't use crankcase heaters on rotary compressors?
Great question. I don’t have that answer for you. Reach out to the system manufacturer and ask them.
What of liquid at SH's below 20F for extended period of time at the compressor the oil droplets displacing oil on the internal surfaces causing friction points, thus scoring & eventually failure.
Great question. It all depends on the refrigerant. Some can run at lower superheats so cannot. Always check the compressor manufactures superheat tolerances.
So I dumbly charged the unit r22 thru the suction as a liquid before I started the compressor up. I’m thinking that i flooded the compressor because it turned on for 5 seconds then tripped the breaker. Would I have to wait for the gas to turn into vapor as it’s been 2 days since I’ve started it, or should I reclaim some of the refrigerant from the suction side?
If you really think you have liquid in your suction line, just use your recovery machine and pump it to the liquid side…
Sorry I didn’t get to this question quick enough. What did you do and what was the result?
Great Information ...
Thank you.
Good ❤
I'm glad you like it
What’s your thoughts on pumping down a scroll compressor to store refrigerant in condenser coil for a t.x.v. Repair
I have done it before but I do prefer to pull the gas out.
@@RefrigerationMentor thanks for responding have a great day
@@eastcoast186 anytime.