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Author Topic: Trane outdoor unit questions  (Read 2472 times)

Offline Jesster

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Trane outdoor unit questions
« on: July 14, 2015, 06:56:24 PM »

My AC system is a Trane XE900 Model TTD730A100A0.  It has been cooling pretty well since replacing the run capacitor but not 100% this year.  I replaced the run capacitor with a factory spec 35mfd 440v Genteq as the one that was in the unit (replaced by a tech in 2011 apparently with a used one and not original spec) was a smaller 370vac 30mfd originally for a Coleman heat pump from what I found on the internet.  When the outdoor temperature gets to around 96-98 degrees and the thermostat is set on 78, the indoor temperature usually goes up to around 80 or 81 degrees and the unit runs pretty much constant until evening.  The capacitor replacement seemed to help quite a bit, but not 100%.  I have cleaned the outdoor coils and the furnace air filter, but it feels as though the large R-22 (3/4") return pipe is not as cold as it should be.  I don't have a gas detector, but I know the schrader valves have never been replaced.  I see that I can buy a schrader (core) valve replacement tool so as to replace the high and low pressure valves.  I have a few questions for the experts on this site.

1.  Is there a valve core removal tool that is recommended, that will replace both high and low pressure valves?
2.  Is there a better brand than most, but more or less on the cheap $30-$40 on amazon, Mastercool, CPS, Robinaire, Yellowjacket?
3.  What size of schrader valves do I need, most of the information that I have found says 1/4" is standard but I didn't know if my unit was different, I have also read that high and low could be different sizes.
4. I believe I need the R-22 topped off and have found that R-44 (Capillary Tube) or R-45 (Thermal Expansion Valve) are good and reasonably priced replacement gases that can be added to the existing R-22.  My Trane Reddi Facts guide that came with the outdoor unit shows either of these or also something called FCCV.  How do I determine what I have?  Do I open up the sheet metal around the A-frame and look for a specific attached device?  I'm only asking because I want to know ahead of time so that when I call a few places for a tech to come out, I can get a decent price per pound rather than getting yanked for one of these gases or having expensive R-22 put back in.
« Last Edit: July 14, 2015, 07:11:34 PM by Jesster »

Offline mz3own

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Re: Trane outdoor unit questions
« Reply #1 on: July 14, 2015, 08:08:22 PM »
mixing refrigerants is a no-no and any tech that offers to do so is not a tech you want working on your home.
Every refrigerant has a different temp glide and requires potentially different oil in the compressor for it to work correctly.
Unless the schrader valve is leaking there is no need to replace it.
+/- 3-5% mf on a cap is ok.
mo99 (r438a) is the closest to r22 in temp glide but, if a tech has to make a repair to the unit and the unit is not rebranded that m099 has been put in place of r22 it can potentially KILL that tech as it has butane in it.

NO you can not "top off" your system with anything other than r22.
If you want to switch refrigerants you will need to have a service company come out reclaim the existing refrigerant. Do a flush, pressure test for leaks, pull a vac and recharge.
« Last Edit: July 14, 2015, 08:18:00 PM by mz3own »