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  1. #1
    Join Date
    Apr 2012
    Posts
    9

    Thumbs up Desert aire becoming a headache

    Ive got a desert aire pd0500. Going off memory. 500 is right. 2006 model. A txv was put in last year. I replaced the txv under warr. Would work fine in dehum go into cool and would shut off on high pressure. Blew out system good deep vac.3 months later unit shutting off on low pressure in both cooling and dehum. Replaced all driers blew out system. Found metal at txv. Looked like sight glass came apart. Replaced it and liquid line solenoid valve with driers. Added one on discharge line and before solenoid valve. Has a factory one on discharge line. Used suction driers for future diagnostics. Anyway i caught it cycling on low press switcch again. No drop across filters. Running great now for 3 days. Only thing i didnt change was solenoid coil. Last time it went down low side was near zero. Put it into cooling and it hasnt acted up in either function since. Something is up short of replacing everthing again without being sure im at a loss. I know its txv or soldnoid. What else could give me an intermittent problem like that? 49' lineset added 26 additional lbs r22. Usually do t see 0 on the gauge. Switch opens at35 closes at 55 or 60. Thinking about removing solenoid as a way of eliminating a possible problem. Readd later. Anyone see a problem with this. Unit rarely shuts off. Txv bulb just like my wife clean tight and on top. Itis a 7/8 line. Scratchin my head thought i had it whipped ( twice). Just started my own biz and this one is kIckin me. Havin to give too much already on this one. Thats why Im proposIng temporarily removing solenoid. Ive always had good luck with these units so im open to advice. Prolly loOkIn me right in the face. Hate intermittent problems. When running outside temp 78 88 inside 55% humidity. Hi 245 lo72. Will bring it back into perameters in no time when out of whack.

  2. #2
    Join Date
    Sep 2006
    Location
    River Forest IL
    Posts
    70
    As far as it going off on high pressure, is it possible the condenser wasn't being energized at the time? Seen that happen before where a relay hung up at times and didn't pull in. Does it have a fan cycling control that might have decided to hiccup? Could be a three way valve not opening fast enough.
    As for low pressure, I'd suspect the LLS. What energizes it? Could that relay be hanging up? You could try bypassing it with a coil magnet (Don't forget to disconnect a coil wire-been there and bought the t-shirt). Could possibly moisture in the system gumming up at the txv, but it sounds like you've covered that with your driers.

  3. #3
    Join Date
    Apr 2012
    Posts
    9
    Not going on off on high pressure anymore. Outdoor unit is running fine. It does have a head pressure control but i can see that cycling with my pressures inside. I have thought about wiring outdoor fan hot. Another temporary thing. Just hate taking so many stabs in the dark. Headed there now. Gonna recover and open lls and replace drier. Get a visual of whats going on inside the sysem. Couple more tanks of nitrogen and a few hours of vac. Show some face at least. Happens again i guess i will eat a txv and HOPE that was it.

  4. #4
    Join Date
    Apr 2012
    Posts
    9
    Got Ahold of factory rep( top notch guy) explained to me the zero reading was telling. Basically when it would satisfy freon would leak out. Been having cooler evenings here. So sometimes it would take off depending on call. Told me to look for low side leak and low and behold hidden behind distributor tubes i found a pinner. When cycled down long enough would lose pressure just on low side thats why it would be working when i showed up only saw the zero once. Said he would bet when i recovered it would be less than th e 51lbs i put in it. Had lost about 9. Staring me right in the face. Always obvious when they are fixed. Keep you posted if more problems arise. Thanks for the help good to have someone to bounce thoughts around with. Fresh eyes can make all the difference sometimes.

  5. #5
    Join Date
    Sep 2006
    Location
    River Forest IL
    Posts
    70
    Just out of curiosity-who did ya deal with? (used to do startups/warranty work on Desert Aire, and dealt with the factory folks quite a bit-great group to deal with. Worked with a couple of them in the field on some head scratchers, and got to meet them on some training up in Wisconsin)

  6. #6
    Join Date
    Nov 2004
    Location
    up in the hizzy
    Posts
    1,375
    seems like a common problem with the newest 410a units licking at the distributor and around the 3 way valve. I think the quality dropped some time ago, even the blower motor mounts are crappy.

  7. #7
    Join Date
    Jan 2007
    Location
    Stongsville Oh
    Posts
    893
    I hate to even bring this up but after your repair, how could you acheive proper evac. I will never charge a system unless I acheive 500 microns or better, even if I have to leave my pump on over night. What equipment do you use for evac? This has been talked about repeatedly on this sight but evacs should not be done with manifold gauges. Tree and evac hses only with shreaders removed. Micron readings with pump isolated from system. Pressure test before evac, leak checking after evac with micron gauge is not a good idea for obvious reasons.
    ckartson
    I didn't write the book I just read it!

  8. #8
    Join Date
    Sep 2006
    Location
    River Forest IL
    Posts
    70

    Evac

    Definitely with you as per proper evac. I've got two 6 cfm pumps that really earn their keep- I shoot for 500 microns too. Had a McQuay rooftop unit that was so contaminated once (evaporative condenser leak, took water in the refrigerant side) that we had 2 pumps on 24 hrs a day for a solid week, stopped in every day to change the oil-this was after doing a flush with RX11. Never did see it lower than 1200 mics. Finally was told to damn the torpedoes-run it. Which we did, followed by 6 suction/liquid line drier changes, as well as oil changes in the compressors. Ultimately lost two compressors.
    One problem is that some bosses have little idea as to what an evacuation is actually for-it's as if they think you're pulling dust out of the piping with a hoover. I know guys that I'd consider to be good techs that shoot for 28" on the gauge, and that's it-never used a micron gauge.
    Oh well, I know sparkys that test 120 circuits with wet fingers...not for me though.

  9. #9
    Join Date
    Apr 2012
    Posts
    9
    Dealt with a guy named pete.
    Legit question on the vacuum.when i said deep vac (eating my words here) i press tested my fittings and ran vac while cleaning up and checking other units.well over an hour on indoor. I isolate condenser early on and ran it for hours. Problem is its a residential unit. The people have no concept of time. Im told to show at 10 call at 9:30. Asked to get there at noon then at 1:30 told she has to pick her mom up at 2. This is a for instance. Basically gotta do a lot of winging it.(cant let gauges sit long)They dont complain about the call backs but they dont want you at their house long.make it work before you leave. Kind of a little honey hole.they have multiple systems. I charge my full price for refrigerant everytime. I dont warranty freon. Not at least on a fitting or part i didnt braze. Im not a hack i do take pride but i gotta work in her time frame. Thats why i would eat a txv or lls if i overheated it lets say i wouldnt b.s. them. There's money to be made here. Use to do work at the husbands office building he owned with a compny i worked for and he HOOKED me up every Christmas. Back to the question lack of time.
    I borrowed an appion tez 8 for this job ( older ) it wouldnt pull below 20 on my gauge. Are they worth the $800? I know the one i borrowed was damaged but my 5 cfm seems to do pretty good showed 200 on a new cps gauge(this last trip). Im leaning more of a residential market in my own biz. Payday everyday. Worth the investment there?

  10. #10
    Join Date
    Apr 2012
    Posts
    9
    Ckartson- just fully read your post. Like i said started my own company i gave up alot of the quality equipment you described for now.babysteps here. Im pulling through my manifold gauges with basic hoses. Have the depressers out and pull through a couple schrader core tools. Bought the appion g5 recovery. Appion rep is coming was told can get a deal on the hose and tree kit then. Just not sure bout the tez8 in the djrection im going. I know Speed is everything but going back to mainly residential and light commercial im not quite sold yet. The accessorries im down with. Good prices. Can someone tell me why a new $ 159 robin aire 5 cfm wouldnt suffice. Or something in the $300 range. What is the difference in a 2 stage 5 cfm unit that is double the price with the same rating? Never really understood. What am i missing. I believe in quality but smart money. Keep in mind im a 1 man show for family reasons i prolly wont get much bigger. Going for small personalized service. Good rates but you might have to wait depending on what i have going on. Make it worth their while. Lived here awhile and know a lot of people and things have really taken off. Also any bookeeping reommendations or ipad apps or threads here?

  11. #11
    Join Date
    Sep 2006
    Location
    River Forest IL
    Posts
    70
    I was crazy enough to go out on my own years back-best of luck to you. I used Quick Books Pro for book keeping-found it to be easy to use with lots of useful features-would make your accountant's job-and therefore your life-easier. HVAC Calc is a great program for load calcs-very user friendly-Don Sleeth did a great job making that program practical.

  12. #12
    Join Date
    Apr 2012
    Posts
    9
    Will- thanks for the tips. Been a worker bee my whole life this is going to be interesting. Not to bore you with details but had to do it out of necessity. Wife of 20 yrs dealing with some issues found out they are genetic so now toss a 6 and 11 yr old in the mix. Why not put everything on the line roll the dice and hope its not snake eyes? LOL. Needing some control of my schedule. Money is secondary. Fortunately wife was a personal banker. Loves numbers. Actually be good for her. Nothing life threatening but life altering. Worst case i go get a job again. Actually having fun right now. The pressure of not working 2700 hrs a year like the last 5 years is a huge relief. Kids are digging it. Gettting to see dad everyday. You guys know how it is. Do appreciate all the fast responses. So far so good on my headache. Slowly working my way back to the quality equip. I once had.Nice knowing there is some quality advice and technical experience out there.

  13. #13
    Join Date
    Jan 2007
    Location
    Stongsville Oh
    Posts
    893
    Hi creek1, sorry, I wasn't questioning your vaccum pump when I asked about the equipment used. Today our vac pumps are usually two stage and capable of 25 microns. CFM should be sized to the system we are servicing but we can't buy new pumps for every occasion. I did have two vac pumps at one company, 1.5 cfm for very small refer systems. It was very light and small. We did some very small stuff like ice machines and waterfountains. then the 6 cfm for normal service. What I was refering to is the use of tree and evac hoses and not using manifold for evac. I know this has been brought up here before but it is a very important point. Back when a lot of us went to school trees and deep evacs where not really taught other than double and triple evac. But now technology has improved and equipment and methods have been upgraded. Robinaires website shows graet combinations of equipment. The customer doesn't know if a company uses the latest or not. Some companies get service jobs because nitrogen for example may not enter into their quote while others costs are higher because of these items. The company I am with bills for an evac charge, reclaim charge, basically the use of the tool and the cost of fresh oil for each use. I wish you luck with your business
    ckartson
    I didn't write the book I just read it!

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