Need appliance parts? Call 877-803-7957 now or use the parts search box:

Parts Search

Tired of guessing on service calls?

Click here to check out our structured, online appliance repair training courses for rookies and experienced techs.

FAQs | Repair Videos | Academy | Newsletter | Podcast | Contact

Stay connected with us...

Samurai on Facebook - become a fan today! Sign up for our free newsletter and keep up with all things Appliantology. Subscribe to our YouTube channel for lots of appliance repair tips and help! Follow the Samurai on Twitter and get timely morsels of Appliantological Wisdom! Subscribe to our MST Radio podcast to learn secrets of the trade.

KSSS42QJT00 - Proper Refrigerant Charge - How to verify/measure?

5 posts in this topic

I've been working on repairs to my Kitchenaid refrigerator (see ) and have become puzzled by the related topic of figuring out how to determine if the amount of refrigerant charge is too low, too high, or just right.


I have the following tools that would seem applicable:

  • Manifold gauge
  • High and low service ports (high is Schrader valve on the dryer, low is bullet piercing valve on the process port stub)
  • IR thermometer
  • Recharge adapter with "conceptually" calibrated gauge (i.e. too low, too high, nice, and something else as ranges).  This little gizmo screws on top of a small R134a container and also into the low service port.

I also have an evacuator pump, as well as a small digital scale, which I'm hoping NOTto have to use.


What I'm missing is the process for determining the proper amount of refrigerant.  In theory I could evac, then recharge using the scale to determine if the 6.7 oz requred had be inserted.  But that seems like overkill, and further is not really useful as a way to spot check given the suspect very slow leak in the system.


Are there any quantitative measurements and procedures I could use to figure this out?  I assume there must be, I just haven't been able to find them.

Share this post

Link to post
Share on other sites

Need appliance parts? Call 877-803-7957 now!

Well,if you do not want to do it correctly,you are only guessing anyway.

The guessing way would be to charge to a low side PSI of 5.

Share this post

Link to post
Share on other sites

Oh yes, this might be relevant.  After coming home from vacation to a warm freezer, I eventually (after some false starts), recharged the system (while obviously slugging the compressor since I had the refrigerant bottle upside down - DOH!).  Anyway, the freezer is now nice and cold - YEAH.  But I was monitoring the high side pressure and after a day it changed from the 130-160 PSI range to around 250 PSI.  I freaked out thinking I had too much refrigerant and/or maybe the capillary tube was blocked by freezing water or other bad stuff I introduced.


So I drained some of the charge at the low process port.  I as surpised to get a few cc's of greasy water (or very very thin oll) along with the warm vapor.  After this the high pressure was more consistent (around 150 PSI).  I also replaced the failed condensor fan.  The unit is currently behaving nicely (hard ice cream!).


So I am left with many questions.  What was that thin oily stuff anyway?  Was removing it good bad or indifferent?  How do I check the charge?

Share this post

Link to post
Share on other sites

The thin oily stuff was oil and other contaminants in the system.

There may also be a high side restriction.

A 134a refrigerator system running correctly would be about1-5 low side psi and 105 or so on the high side.

Share this post

Link to post
Share on other sites

Thanks for the response.  Let me expose more of my ignorance:


Low side Pressure:


  • When you say (for example) 5 PSI on the low side, is that 5 PSI above standard atmospheric pressure, or 5 PSI over a full vacuum?
  • Secondly, I assume this is when the compressor is running (since when it is not the pressure tends to equalize between the low and high side) -- Am I understanding this correctly?
  • I seem to remember when I had the manifold gauge hooked up that the compressor pulled a vacuum on the low side (and the gauge switched from PSI(g) to measuring inches of mercury (I guess to avoid negative numbers of something -- it seemed odd until I realized this must be a common convention in the industry).  How eactly does this relate to the recharging process, or was this vacuum simply a side effect of far too little refrigerant in the system?

"The thin oily stuff was oil and other contaminants in the system"

  • Does that mean that letting it flow out was a GOOD thing?  Or is the oil something that should be replaced at some point?

Thanks for your help!!!

Share this post

Link to post
Share on other sites