Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-15-2011, 01:38 PM   #1
Member
 
Join Date: Jul 2011
Posts: 150
Rewards Points: 0
Share |
Default

Charging Procedure


Hi Guys,

YASQ ( Yet Another Stupid Question )

So after leak checking and triple evacuating this system, it'll be time to charge it. The spec for the Goodman 2.5ton R22 condenser is 88 ounces, AKA 1.5 pounds.

The big refrigeration book is just a little vague about the procedure. They talk about vapor or liquid charging into the low side. Vapor charging sounds safer. But will it take so long as to exhaust even my extreme patience?

Of course, there is no "low side" or "high side" until you start the compressor. Which I imagine you must NOT do until there is a decent amount of refrigerant in the system, because the motor depends on the refrigerant for cooling. How much refrigerant do you put in before starting the motor?

I like that this system has a TXV, so I don't have to muck about with "desired superheats" and wet bulb temperatures.... The checking procedure seems very precise.

- JerryK

jerryk1234 is offline   Reply With Quote
Old 08-15-2011, 01:55 PM   #2
Member
 
Join Date: May 2010
Location: San Antonio
Posts: 391
Rewards Points: 0
Default

Charging Procedure


as a novice, i take the time to charge from the low (vapor) side because i'm not an expert and i can take my time that way. with a TXV, you focus on subcooling for charging because superheat is controlled by the TXV.

you do charge the system when it is running, i'm not sure if there is any initial procedure to take when there is no gas in the system at all. i've always worked on the evaporator side of the system so was able to pump it down (store all the remaining refrigerant in the condensor) and then let it loose once i pulled a vacuum. so there was always some amount of gas in the system before i charged it up.

NitroNate is offline   Reply With Quote
Old 08-15-2011, 02:00 PM   #3
fabrk8r
 
fabrk8r's Avatar
 
Join Date: Feb 2010
Location: Iowa
Posts: 849
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by jerryk1234 View Post
The spec for the Goodman 2.5ton R22 condenser is 88 ounces, AKA 1.5 pounds.

88 oz. = 5.5 lbs

Also, take into account any extra line set over the 15' already accounted for in the initial charge. Usually add .6 oz. per foot of line set over 15'. The condensing unit installation manual will have the specifics.
__________________
"The physician can bury his mistakes, but the architect can only advise his clients to plant vines." -- Frank Lloyd Wright
fabrk8r is offline   Reply With Quote
Old 08-15-2011, 02:06 PM   #4
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 9,421
Rewards Points: 64
Default

Charging Procedure


it comes precharged with the entire charge inside the condensor unless you buy a special unit which is dry charged/empty and I am not sure why they sell those but some brands do (AireFlo apparently). you still need to check the subcooling with a TX valve or ANY type of metering device /superheat on orifice units( except for minisplits which are weighed in).
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 08-15-2011, 02:07 PM   #5
Member
 
JJboy's Avatar
 
Join Date: Oct 2010
Location: Austin - Texas
Posts: 1,402
Rewards Points: 0
Default

Charging Procedure


Unit is under vacuum, R22 cylinder on top of digital scale, scale properly reset. Just open the R22 cylinder, refrigerant will travel from high pressure to low pressure until equalize. Turn on the A/C unit until scale shows 5.5 pounds. After that, you need to do fine adjustment with subcooling.
__________________

**Always kill the power ** Hot air rises, but heat will always move from higher to lower temperatures. ** Real man shoot in manual. ** If it ain't grounded, it ain't dead.
JJboy is offline   Reply With Quote
Old 08-15-2011, 02:26 PM   #6
Member
 
Join Date: Mar 2010
Location: S.E Michigan
Posts: 62
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by JJboy View Post
Unit is under vacuum, R22 cylinder on top of digital scale, scale properly reset. Just open the R22 cylinder, refrigerant will travel from high pressure to low pressure until equalize. Turn on the A/C unit until scale shows 5.5 pounds. After that, you need to do fine adjustment with subcooling.
Yep, That's how you do it. Digital scale. I doubt the compressor will run with no freon in it. Don't forget to add the line-set capacity.

D
StahlMaster is offline   Reply With Quote
Old 08-15-2011, 04:14 PM   #7
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Rewards Points: 0
Default

Charging Procedure


shut the disconnect off for the condenser...take a single refrig hose hook it up to the freon can and crack the valve on the freon slightly..to bleed the hose line....as it is bleed out the hose connect it to the liquid line then flip the freon can and go have a beer the vac will suck the liquid in and the condenser will pressurize and the evap section inside will equalize thru the TXV.after 30 minute flip the can uprite shut the valve and disconnect the hose off the LL...your still not charged.start the system and add ONLY GAS into the suction...never liquid nobody is in that much of a hurry....
biggles is offline   Reply With Quote
Old 08-15-2011, 04:40 PM   #8
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 25,101
Rewards Points: 98
Default

Charging Procedure


With system under vacuum. Connect your charging hose to the R22 cylinder, open the tanks valve, then loosen the hose at the manifold to purge out any air. only takes half a second of purge time. Then set tank upside down on scale and zero the scale. Open the high side gauge and add liquid until either you have the correct charge in, or it won't take anymore, which ever comes first.

Then start system. If additional charge is needed, you can add liquid through the vapor side safely by only opening the gauge enough to have 10 PSIG above what the vapor was reading(I haven't charged by vapor since I can't remember when, on systems that hold more then a few ounces(it would take me forever to get the last 30 to 50 pounds into some of the systems I work on).
beenthere is offline   Reply With Quote
Old 08-15-2011, 04:58 PM   #9
Member
 
Join Date: Jul 2011
Posts: 150
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by fabrk8r View Post
88 oz. = 5.5 lbs
*** Of course. Duhhh
Quote:
Originally Posted by fabrk8r View Post
Also, take into account any extra line set
*** I was thinking to disregard this in order to guarantee that the charge would be low. That way, I would sneak up on the correct charge by adding more - instead of having to recover some.

- JerryK
jerryk1234 is offline   Reply With Quote
Old 08-15-2011, 05:02 PM   #10
Member
 
Join Date: Jul 2011
Posts: 150
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by yuri View Post
it comes precharged with the entire charge inside the condensor unless you buy a special unit which is dry charged/empty and I am not sure why they sell those but some brands do
*** Goodman, for R22. I guess they don't want to sully their hands with the evil.

[quote=yuri;707930]you still need to check the subcooling with a TX valve [/quote

*** Of course. But it's so much simpler. Subcooling of 7F, superheat 8F - regardless of indoor temperature, outdoor temperature, wet bulb temperature, or any other temperature.

- JerryK
jerryk1234 is offline   Reply With Quote
Old 08-15-2011, 05:32 PM   #11
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 9,421
Rewards Points: 64
Default

Charging Procedure


Wait until we take you into the dark zone and tell you everything varies according to the cfms across the evap coil/duct size etc etc. The charging chart with the unit is based on the airflows Goodman expects. There is NO arbitrary rule of thumbs for superheat/subcooling. That is why people hire experienced Pros with many years experience to setup their unit properly. Unfortunately those are very hard to find and you may do as good or bad as some of those locals or hackers out there anyway.
__________________
"Cut it twice and it is still too short".

Last edited by yuri; 08-15-2011 at 05:35 PM.
yuri is online now   Reply With Quote
Old 08-15-2011, 05:51 PM   #12
fabrk8r
 
fabrk8r's Avatar
 
Join Date: Feb 2010
Location: Iowa
Posts: 849
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by yuri View Post
That is why people hire experienced Pros with many years experience to setup their unit properly. Unfortunately those are very hard to find and you may do as good or bad as some of those locals or hackers out there anyway.
...or more better maybe.
__________________
"The physician can bury his mistakes, but the architect can only advise his clients to plant vines." -- Frank Lloyd Wright
fabrk8r is offline   Reply With Quote
Old 08-15-2011, 06:05 PM   #13
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 9,421
Rewards Points: 64
Default

Charging Procedure


BUT "only the Shadow knows what evil lurks in the heart of men" or the lines of that AC unit. Bwahhahahaha.
Attached Images
  
__________________
"Cut it twice and it is still too short".

Last edited by yuri; 08-15-2011 at 06:20 PM.
yuri is online now   Reply With Quote
Old 08-15-2011, 06:19 PM   #14
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by jerryk1234 View Post


*** I was thinking to disregard this in order to guarantee that the charge would be low. That way, I would sneak up on the correct charge by adding more - instead of having to recover some.

- JerryK
Good idea. I'd even stop at 4 lbs and SLOWLY add from there as needed. The last couple dry Goodmans I worked on took less then the name plate stated even with 20' lines.
Marty S. is offline   Reply With Quote
Old 08-16-2011, 08:56 AM   #15
Member
 
Join Date: Jul 2011
Posts: 150
Rewards Points: 0
Default

Charging Procedure


Quote:
Originally Posted by yuri View Post
Wait until we take you into the dark zone and tell you everything varies according to the cfms across the evap coil/duct size etc etc. The charging chart with the unit is based on the airflows Goodman expects. There is NO arbitrary rule of thumbs for superheat/subcooling.
*** Even with a TXV? According to both the Goodman install manual and the Big Book, a TXV actively regulates the superheat, compensating
for all of the above variables.

Moving to the dark side, the above assumes that the @#$# thing actually works. If it doesn't, or if it works intermittantly, I'm sure it can produce some mighty confusing symptoms.

Quote:
That is why people hire experienced Pros with many years experience to setup their unit properly. Unfortunately those are very hard to find and
Yes indeed. People who are skilled, honest, and caring are hard to find in any field. Let me tell you my Fresno story:

---------------------------- Fresno story starts here ---------------------
I own and operate an apartment complex in Fresno, CA. Fresno is known for it's hot summers and bad air. I have personally seen a wall thermometer (in the shade! ) showing 113F. AC is a big deal down there, and each of my apartments has a 2-ton Ruud with a roof mounted condenser. After two false starts, I found a really good AC contractor, a guy who fixes it once and fixes it right. His techs don't just "top it up", they find the leaks. In the off season, I have him do maintenance projects, like cleaning the condensers or replacing condenser fan motors.

The local power company has a program they call "Energy Partners" where they pay local contractors to install energy improvements in customers equipment. Mostly light fixtures, weatherstripping - but they also dabble in AC.

One day, a contractor showed up at my complex offering to seal all my ducts and top off my ACs for the cost of the power company rebate. In other words, they would do this for free and I would send them the rebate when I got it. They also offered to replace all my electrical fixtures with new fluorescents. Not knowing what I know now, I thought that sounded like a good deal, and signed on the dotted line.

Imagine my surprise when staff called me and told me that the compressor of one of my two-ton Ruuds had *exploded*. I then paid my contractor to walk the roofs and check every single unit by the superheat method. Several of them had been grossly overcharged.

I'm sure I can do better than those yahoos.
----------------------------- end of Fresno story -------------------------

- JerryK

jerryk1234 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Contractors Procedure for Quoting acerunner Off Topic 3 06-14-2010 03:20 PM
Dell Laptop Charging Cord. brokenknee PC Repairs & Upgrades 4 01-09-2010 07:56 AM
Is charging a R410a system the same as a R-22 system... paulie pizza HVAC 31 06-30-2009 10:20 AM
Sanyo mini-split install air purging procedure. s34n HVAC 3 06-09-2009 06:24 PM
Charging Split Systems Rskog586 HVAC 3 05-27-2009 12:12 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.