INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

System Pressure R-410A

System Pressure R-410A

(OP)
HI Everyone ,

I have Gree Concealed duct type AC units , runing on R-410a , what are the working pressures for the 410a on the liquid side and on the suction side ( all tech have there own ideas what the pressure should be ) , how we come to a conclusion that the system charge is ok


the problem is that the units are not cooling at all ( thermostat set at 16-18C and room temp stays at 30-31C
the other day i took the following reading on a 4 ton ac unit

high side pressure : 250 psi
high side actual line temp near the indoor unit : 25 C

low side 150 psi
low side actual line temp on suction : 10 C

lets say i have a freshly vacuum unit i need to charge , what parameters should i be looking at inorder to now that chrage is ok ,

the unit have electric expansion valves

plus the outdoor unit have no details for subcooling and the mentioned opr/press id very high , * Attachment *

please advice

RE: System Pressure R-410A

First thing, convert psi to MPa. Better yet use a pressure gauge that reads in Pa/MPa. Using the same system of units solves so many problems and answers so many questions that get posted here.

4.2 MPa is the operating pressure (right on the nameplate). If the pressure you are getting is down 10-15%, you probably need more refrigerant. Consult your user's manual to be sure or call Gree Electric Appliances, Inc. of Zhuhai.

Second, you are looking at a heat pump. Verify the system is in cooling mode.

RE: System Pressure R-410A

http://www.hvaceducationaustralia.com/Resources/PD... states that the working pressure should be around 410 psig, which is consistent with 4.2 MPa maximum allowable pressure.

Note that your picture of the nameplate also clearly shows an operating pressure (hi/lo) rating = 4.2 MPa/2.5 MPa, which implies the operating pressure is supposed to be between 609 psig and 363 psig, so your measured pressure is well below the manufacturer's nameplate pressure.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: System Pressure R-410A

(OP)
1st i could not find any datasheet or user guide online ( regarding the unit charge for the specific unit ) ,

and the mentioned pressure are way to high , since i already tried to charge on these pressure and it give continuous error for high pressure ,

RE: System Pressure R-410A

What is the outdoor temperature around the condenser?

PT chart for R-410A. http://www.arkema.com/export/shared/.content/media...

If your low-side readings are accurate it seems your expansion valves are not working correctly. Are their temperature sensors installed correctly?

RE: System Pressure R-410A

"and the mentioned pressure are way to high , since i already tried to charge on these pressure and it give continuous error for high pressure ,"

Your high side temperature is basically room temp, so you're essentially doing zero compression. Otherwise, the high side would be quite hot, from the work added by the compression process.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: System Pressure R-410A

(OP)
@MintJulep

the out door temp was around 47-48c * very hOt *

@IRstuff

But as high as mentioned in the nameplate i believe its way other the operating pressure for 410

RE: System Pressure R-410A

Condenser temperature is 25C while outdoor temperature is 45.

First law. No heat is leaving.

Read dbill74,'s post again.

RE: System Pressure R-410A

You need to have a tool that measures pressures and the lien temperatures. That tool has a database and calculates superheat and subcooling. the device manufacturer tells you what subcooling or superheat you need to have. You should do that under load.

Hope you are not charging yourself, you need to be EPA certified and need to know what you are doing. Testo and other companies have the tools.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close