5 or 6 ton split unit cycles.

[romac]

Hi. Some one worked on this unit before me and the unit cooled but not enough. Recovered 5.5lb of 22 instead of 9Lb 6oz. Replaced 2 rusty filter/dryers before condenser and after condenser. After recharging with correct amount the unit runs 4 seconds while the low side pressure drops to 25psi and the pressure switch cuts off. After pressure rises back it comes on and all same repeats. Don't know what I have done wrong. Thanks.:eek:

[Brian_UK]

Don't know what I have done wrong.

Well neither do we.

Did you pressure test it and did you pull a good vacuum?

[Grizzly]

romac
Assuming you have done everything correctly, as Brian suggests.

It sounds as if the LP side of the system as McM suggests is at fault.

That said It's a good compressor that will pump down in 4 seconds.
Also you say 2 Liquid line filters, 1 before the condenser (that's strange?). The 1 after, I can understand.

21psi is -20c which is a very low pressure temperature.
What type of filters did you fit.
Also check liquid line solenoid valve is working ( if fitted ) check your metering devise. what type is fitted.

Lastly have you proved the pressures you are quoting or have you a rogue sensor or transducer??
Sorry I cannot be more precise but you give very little info to work with.
Grizzly

[romac]

I did pressure test and good vacuum. One of those filter/driers was in reality a mufler where I by mistake installed another filter/dryer. I have to redo it tomorrow and then I post an update.
Thanks.:o