older Carrier reversing valve energized in cooling or heating?
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  1. #1
    Join Date
    Jul 2012
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    Albuquerque, NM...USA
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    30

    older Carrier reversing valve energized in cooling or heating?

    Model 50JX 060 ---301 I believe to be about 2001. Heat Pumps are uncommon in Albuquerque, NM and I need some help. Original call found a bad indoor blower capacitor that was replaced but I was suspicious of the heat pump operation (assumed it was operating on heat strips). Had another call within a month, I found the defrost thermostat wires were shorted to the frame popping the LV circuit breaker. Also the reversing valve wires had been or were shorting. My guess was that all the shorts probably fried something, but after all my bypassing and LV testing, now it decided to work - maybe. I downloaded an excellent article from ZenHVAC and I contacted my distributor and the conventional wisdom is that the reversing valve is energized for cooling. This one seems to be the opposite! After all the crap above, my question is simple: should the reversing valve be energized in heat as I suspect or cooling as others suggest? Additionally I could not get the heat relays to function independently and wonder if there is delay built into these relays? They are unlike the heat sequencers I have worked with. I have the factory literature and wiring diagrams and am still unsure of the exact sequence of operation because there is none.

  2. #2
    Join Date
    Jan 2011
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    Highland Park, CA
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    You can test the RV by just disconnecting the control wiring and see which mode it defaults into. Then make sure when you send 24V on your control wiring it switches modes. So whatever t-stat you're using should be wired appropriately (O or B). It should be energized for cooling, but unless you are the only tech who's ever worked on it you have to investigate.

  3. #3
    Join Date
    Jul 2007
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    Virginia
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    Quote Originally Posted by Kemp View Post
    Model 50JX 060 ---301 I believe to be about 2001. I contacted my distributor and the conventional wisdom is that the reversing valve is energized for cooling. This one seems to be the opposite! After all the crap above, my question is simple: should the reversing valve be energized in heat as I suspect or cooling as others suggest?

    I have the factory literature and wiring diagrams and am still unsure of the exact sequence of operation because there is none.
    The Reversing Valve Solenoid (RVS) is energized in cooling.

    Has some one changed the thermostat lately, and accidentally wired it to the "B" terminal, instead of "O"?
    Instead of learning the tricks of the trade, learn the trade.

  4. #4
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    Sep 2012
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    Missouri
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    I worked on a Ruud 2T, 1998 model last month that energized in heat mode. first one I have seen.

  5. #5
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    Jul 2007
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    Virginia
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    Quote Originally Posted by JES View Post
    I worked on a Ruud 2T, 1998 model last month that energized in heat mode. first one I have seen.

    All Ruud/Rheem energize the reversing valve in heat.
    Instead of learning the tricks of the trade, learn the trade.

  6. #6
    Join Date
    Jul 2012
    Location
    Albuquerque, NM...USA
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    Thanks for the help. I'm definitely not the first to work on it. Someone used a swamp cooler motor pigtail to hook up a crankcase heater although the diagram says only used for 3 ton. I tried to install a 2 stage HP w emergency heat t-stat and I could not even get the heat strips to energize. I have the wiring diagrams and I guarantee the low voltage was correct t-stat wise. I disconnected the low voltage at the transformer to board and TDR and put 24 volts straight to the heat strip relay(s) and they would not energize. The existing single stage Honeywell t-stat had w wired to the unit orange reversing valve wire. On call for heat the IBM immediately starts even with green disconnected. The reversing valve energizes but the compressor does not start immediately nor even after several minutes. I gave up and put the old stat back on wired as I found it and collected my tools and was off the roof before the compressor finally kicked in and I was soon getting 120 deg air. I never even got the compressor to energize while I was on the roof by jumpering the control wires to call for heat or cool, but I never waited 10 min. for something to happen either. I think the defrost board is screwy or maybe mis-wired; I did not check all the terminals to make sure - yet. I like to actually figure out what's wrong before I start just replacing things. It actually is heating, but it can't possibly be working as designed. I may have to do it on my own time, but I want to solve the problem. I will by-pass the D board and TDR and power the compr. contactor directly to check the reversing valve default position

  7. #7
    Join Date
    Jan 2004
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    Lancaster PA
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    67,588
    Quote Originally Posted by rundawg View Post
    All Ruud/Rheem energize the reversing valve in heat.
    Except their commercial 3 phase units(older ones that had the fans with the cables). Threw me for a loop some years ago.
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  8. #8
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    Jul 2007
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    Virginia
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    Quote Originally Posted by beenthere View Post
    Except their commercial 3 phase units(older ones that had the fans with the cables). Threw me for a loop some years ago.
    Thanks for that tip.

    Nothing worse then starting a job thinking you know how a system should operate, then an hour later you look at the wiring diagram and find out otherwise.
    Last edited by rundawg; 02-08-2013 at 06:48 AM.

  9. #9
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    Feb 2012
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    Durham, NC
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    Quote Originally Posted by rundawg View Post
    All Ruud/Rheem energize the reversing valve in heat.
    If I can correctly recall, they use blue as the reversing valve and brown as common also. Crazy ruud/rheems!

  10. #10
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    Feb 2009
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    Tallahassee, FL
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    Reversing valves - single inlet always true discharge.

    Middle of the three always true suction.

    Then depending which way you spin the valve (coil facing or away) is either energized in cool or heat.

  11. #11
    Join Date
    May 2009
    Location
    Savannah, Ga/H.H. Island, S.C.
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    1,392
    Someone could have replaced the reversing valve and put it in backwards! Haha.

    Saw that one a few years back on a HP split system at a church.

  12. #12
    Join Date
    Jul 2012
    Location
    Albuquerque, NM...USA
    Posts
    30
    Thanks again for the replies. From the tenant's point of view the thing is working, so why do I need to come back? I haven't been back on the roof since before the first post. I decided that the original single stage t-stat is probably still set to gas not HP. I think it is doing a 10 minute defrost although the compressor is not energized then the reversing valve is de-enrgized and the compressor starts. Possibly the terminals on the board are mis-wired. I don't know why it's heating at all. Again the initial issue was a grounded defrost t-stat wire popping the circuit breaker.

  13. #13
    Join Date
    Mar 2001
    Posts
    1,480
    i've got an old carrier control box with a bunch of leads and alligator clips on it that I bought back in the early 80s. Kind of an early precursor to a Zebra stat. I'd just disconnect all the Tstat connections at the unit, hook up my carrier gizmo, and run it thru it's paces. Sounds like control problem on roof, or Tstat. I remember older Carrier pumps that ran using a heat-cool T87 stat.
    One way to outthink people is to make them think you think. They'll think you're not really thinking what you're trying to get them to think you think...........

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