the compressor contactor load side while the compressor is operating. The most accurate way to measure what is occurring at the compressor is to read the voltage at the compressor terminals. For example, if: L1 to L2 is V, L2 to L3 = V., and L3 to L1 = V. the average is + + divided by 3 or V. Average. Manually when there is no solenoid valve in the system and the technician closes the liquid line valve manually for the pump down of refrigerant into the condenser. The compressor will pump refrigerant into the condenser and/or receiver, pumping it from the low side of the system.
The cause of the oil trapping should be identified and repaired in a timely fashion. If the additional oil returns to the compressor, it could cause damage as a result of oil slugging or excessive oil pumping.
Once the compressor is off, front pumpp its discharge service valve, which will completely isolate the compressor hermetix the system.
Carefully loosen the oil drain plug rown allow the oil to seep out of the compressor around the thread of the plug until enough oil has been removed. Note: Do not totally remove the plug from the compressor. Only allow the oil to seep around its threads. Attach a gauge manifold to the access ports of the suction and discharge service valves.
Using dry nitrogen, pressurize the compressor crankcase through the suction service valve's access port to about 5 psig. The oil should drain from the compressor. If what is a price checker, repressurize the crankcase what to do when appraisal comes in low refinance dry nitrogen.
This method is more time consuming, but it will allow oil to be removed from a compressor. Before using this procedure, make sure the compressor does not have an oil drain plug. Removing oil from a compressor using its oil drain plug is normally a much easier process. What does 4 factorial mean Marchese is owner of Coldtronics of Pittsburgh.
Learn More This website requires certain cookies to work and uses other cookies to help you have the best experience. Odwn Reprints. Occasionally a technician may need to temporarily add oil compresaor a semi-hermetic reciprocating compressor to maintain an adequate oil level, if the oil has been trapped out in the evaporator or suction line.
Pump down Failure on Liebert (Carlyle Semi hermetic)
Jun 11, · When the compressor cycles off, the control shuts the liquid line solenoid valve and runs the compressor until the low pressure switch opens. If the low pressure switch closes it re-pumps until the switch opens. After the seventh re-pump in . Apr 03, · Removing Oil From a Semi-Hermetic Compressor 1. Pump the system down to 1 to 2 psig. 2. Shut down the compressor. 3. Once the compressor is off, front seat its discharge service valve, which will completely isolate the compressor from 4. Carefully loosen the . Apr 17, · On most semi-hermetic comps there is an access plug to both HP and LP side of the head. they take there pressure from the low side and high side of the cylinder head. The compressor pump down was a success! Thanks for your help. KETTLER , AM # LRAC. View Profile View Forum Posts View Blog Entries View Articles.
Remember Me? What's New? Page 1 of 2 1 2 Last Jump to page: Results 1 to 50 of Thread: Compressor Pump Down. Compressor Pump Down. Q: Will the compressor trip the high pressure switch if the refrigerant is trapped in the liquid receiver?
Q: What is the procedure to recharge the compressor with refrigerant? Re: Compressor Pump Down Yes. Close the liquid outlet valve of the receiver and let the compressor run. Details: Have your gauges connected to both the low and high side of the compressor. Watch the high side to insure that the receiver does not fill up with liquid and cause your discharge pressure to rise above a reasonable level because it is rising into the condenser. Relieve the high side pressure into the suction and do another pump down cycle.
If all is well, you have a small amount of vapor to recover with your recovery unit. I am sure there are other techniques used by others. I will read their responses to see if there are better ways. Do I pull a micron vacuum on the compressor head and then charge it with some refrigerant after I install the new pressure switches? Re: Compressor Pump Down. Thanks Dan, Do I pull a micron vacuum on the compressor head and then charge it with some refrigerant after I install the new pressure switches?
Originally Posted by taz So, my proceedure seems to be as follows: 1. Run the compressor until a vacuum is achieved. Remove the existing pressure switch probes and replace them with the new switch probes.
Re: Compressor Pump Down g day kettler try this, put your gauges on the comp high and low sides I really like your idea to purge the air out of the compressor head using the HP gauge hose. Originally Posted by frank. How can you have the high and low pressure tappings connected to the compressor head?
How did you paste that pic in your message? What about diagrams, bmp's, etc? Originally Posted by slingblade. Vent high to low through the manifold set.
On most semi-hermetic comps there is an access plug to both HP and LP side of the head. Cheers taz. Re: Compressor Pump Down g day kettler i dont want to be rude or offend but this is basic friggie stuff mate I like to thoroughly think things through before I start turning wrenches. I think you can see from this string that there are many ways to 'skin a cat'. Thanks MRC Guts. Re: Compressor Pump Down I have been following this thread with interest.
I choose not to respond to this initially because of the nature of the basic question. One of the members mentioned this is "first year stuff" and he is exactly right. If a person has been working on refrigeration systems for some time and does not know how to pump down a compressor, something is wrong with this picture.
If all else fails, ask for help. We don't need schools, university and educator now do we. As sherlock says, ''Elementary my dear Watson''.
Good luck ya all Adios Amigo. Because I smell a rat. Re: Compressor Pump Down hi there! Option 1. If there is a shut-oof valve on both inlet and outlet of receiver then apply this procedure Option 2. Pumpdown the refigerant. Use a vacuum pump to remove air from the gauge lines with the compressor valves front- seated close.
Then open the valves to almost intermediate position which will allow reading to be registerred on the gauge scale and also allow you to quickly close them later. Run the unit and pumpdown will begin if the compressor cut-out too early on the LP swith , then readjust the cut-out pressure to cut out at a pressure under vacuum. Close Frontseat inlet of receiver. Then the decision is left with you 7. When the compressor cuts-out on a pressure below vacuum, then quickly front-seat both compressor valves.
Re: Compressor Pump Down Thank you. My research has led to the adoption of the following procedure: 1. Jumper the LP switch. Run the compressor. Ive seen danfoss ones replaced with ranco and on one the lp is on the lefthand side and on the other it was on the rigthhand side, so when changed it had the Lp hose going to the Hp switch and vice versa. And any connections you disturb really need pressure testing with OFN to be sure you have no leaks and the evacuating.
Cheers Jon. I'll add the following step to my procedure: 8a. Thanks Jon, I appreciate the heads-up! What's an "OFN"? Thanks Taz. Thanks for your help. Re: Compressor Pump Down You must be one of the most fortunate forum members who has scrapped through on the information supplied to carry out out a simple pumpdown on a compressor. Do yourself a favour and get some proper training in this trade, if you have a certificate it must have been done on your computer.
It's impossible to make anything foolproof because fools are so ingenious Don't ever underestimate the power of stupid people when they are in large groups. Please, don't teach me how to be stupid No job is as important as to jeopardize the safety of you or those that you work with. Re: Compressor Pump Down So true, oh so true. Re: Compressor Pump Down Hi Kettler Your opinion of me is'nt me, its just your opinion Out of the six billion people on the planet surely one will think i'm an idiot, now he's got a name Cheers Jon.
What kind of people are YOU? I thought this was a dignified website! Do you conduct business in the manner I experienced? Very poor. I think you people are the amatures! Join Date Jun Location N. Ireland Age 47 Posts 1, Rep Power First off, I made no sarcastic comments.
It was YOU folks who used my inexperience and simple questions to validate yourselves by shamming me. Second, step 8 is intended to purge the air from the compressor head, and, was given to me by someone else on this thread. I actually purged the air from the head using an R22 bottle. I fed the refrigerant through the suction service valve access port and bled it out from the discharge service valve access port.
Originally Posted by US Iceman. Just because you get multiple opinions on how to do something does not mean they are all correct. Re: Compressor Pump Down I hate to see a good discussion go down the drain such as this one has. I saw some good advice and I saw you accepting it. Perhaps too much good advice caused the confusion. Let's not be angry with one another. I would just shut the suction valve while the comp is running.
Then when the comp shuts down shut the discharge valve. The amount of gas in the comp will be minimal. To get the pressure even lower short out the lp switch and let the comp run into a vac. When all valves are closed vent the discharge gas from the comp head back to the suction and that will reduce further any gas loses.
Change the switches and then test like normal.