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Heat pump, "B" stays energized

Feel like I'm losing my mind. 
I have wired hundreds, if not thousands of heat pump systems And I have never noticed the "B" terminal always closed with the thermostat set in heat mode.
No call for heat. B and R always closed.
  I checked this with 5 different thermostats. (3) honeywell T6, (1) PRO IAQ 725 and a Whalen thermostat that is made for the Whalen water source heat pump I'm working on. 
 What makes this even more baffling to me is that this is the simplest kind of heat pump I've ever had to wire. It's only 4 wires. R, G, Y, B. 

I get the call yesterday evening. No heat, water source heat pump. 
When I walk in the door the owner tells me up front he replaced the thermostat when they moved in at the end of the summer. It Worked for cooling, Nothing for heating. He installed a T6, purchased from home depot. 
Walked over to the unit and heard a buzzing like a relay was on and the unit had a call for heating, but nothing was turning on.

I shut it down, checked the t-stat connection, cleaned them up, turn unit back on to take some voltage readings and check the parameters set up in the T6.

Turned out it was set up for a conventional system, not a heat pump. Easy right?
I make the adjustments, tell the thermostat it's working with a heat pump so the compressor ("Y" terminal) and reversing valve have power with a call for heat. Turn unit back on and as soon as I do.... buzzing. No call for heat. Power is going to the RV. 
I pull the thermostat, buzzing stops. I ring out the pins on the T6 (still no call for heat) and the circuit is closed between R and B. 
I switch the mode to off. Still R and B remain closed. 
I call honeywell tech for peace of mind that I'm not wrong and unless there a call for heat, I should not have power to the reversing valve. Especially with the thermostat in the off position. 
Honeywell tech support confirmed what I thought saying "there's no reason the B terminal should be energized without a call for heat. The thermostat must be defective." 
Straight from the horse's mouth. 
I didn't have a replacement on the truck and te owner didn't have a problem picking one up to day and plugging it in. I told him to call me if he had any trouble.  
11:00 today he called.  Said he got the same T6, set all the parameters I showed him in the book, plugged it in and got the same results.  Reversing valve energized without a call for heat. 
I told him I would be back with a different thermostats. I picked up 2 thermostats, another T6 (pro) and a PRO IAQ. 
Before going in I put batteries in both of then and tested in my truck. 

Stick with me because this is where things start getting wired.  

First I set up the T6. Not only was B energized even with the thermostat mode off.... the Y would not energize with a call for heat. 

No my heart is pounding and the migraine is starting. 

So I set up the PRO IAQ and for a moment, the world made sense again.  B  and Y terminals only energized with a call for heat. 
Relived, I go inside, mount the IAQ t-stat, power up and then the unit starts buzzing. 

F

Unplug the IAQ, ring out the pins, B is energized if the thermostat is switched to heat. 

Then I check the 2nd T6 the owner bought and I got the same results from the pro model I bought from Johnston supply. B energized constantly, Y had nothing with a call for heat. 

I'm at a complete loss for words as I kneel on the floor in front of this unit staring off into space trying to comprehend what's happening here.

After a few minutes, I asked the owner if I could look at the other system in his condo to see what that system was doing. 
All the condos in this building have 1 to 3 of these heat pumps. The other system in this condo still had the Whalen t-stat. 
To my surprise...my only saving grace... unless the thermostat was set to cool, the RV was buzzing. 
The owner, after being with me every step of the way was just as relived as I was.  Not happy, but relived that it appeared thats how the system operates. 

He thanked me for doing my job. I left with the units buzzing, my head spinning, still trying to fathom wtf just happened. 
5 thermostats... all of them energizing a reversing valve without reason.  

Please... if you read this and you have a heat pump with a heating energized RV... can you check to see if the RV is energized without a call for heat? 


Happy new year 

Comments

  • WMno57
    WMno57 Member Posts: 278
    Does the thermostat send the call for heat directly to the RV relay?

    or

    Does the thermostat send the call for heat to a Whalen control board? And the Whalen control board controls the RV relay.

    If the control board is in the middle, then either the RV relay is supposed to buzz, or all five control boards have a problem.
  • ratio
    ratio Member Posts: 3,046
    I always though it could go either way, energized for the duration of the call or the duration of the mode change. I do recall some oddball piece of equip. (maybe a PTAC) that specifically said it needed a stat that held the reversing valve active during the entire time the mode was active vs just during a heat/cool call. I also know the house I'm in the middle of buying switches the reversing valve during a cooling call (It's quite audiable…), but I suspect it's got a non-heatpump thermostat on it, as it's dual fuel but I've never seen it in heating mode. I can't wait to get a chance to fool around with it!
  • AMservices
    AMservices Member Posts: 601
    WMno57 said:
    Does the thermostat send the call for heat directly to the RV relay? or Does the thermostat send the call for heat to a Whalen control board? And the Whalen control board controls the RV relay. If the control board is in the middle, then either the RV relay is supposed to buzz, or all five control boards have a problem.
    From t-stat, directly to RV. 
  • Ironman
    Ironman Member Posts: 6,705
    Every heat pump stat that I know of - back to the old mecury ones - energizes "O" when it's turned to "cool" or "B" when it's turned to "heat". They have to do this or the reversing valve would shift with every cycle - an undesirable situation.

    There has been a recall on the first and second generation T6 stats because of them doing wired things. You need to look on the side of the box for wording that's says something like "revision 2" or similar.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • AMservices
    AMservices Member Posts: 601
    I called honeywell when I found the first T6 energizing the RV, even when the t-stat was off. 
    Tech support said that shouldn't be happening.  
    Only time the RV isn't powered is when t-stat is in cooling mode. 

    And yes, "O" powers RV for cooling, "B" for heating. That hasn't changed. 

    If anyone has a heat pump t-stat on there truck and it board today, check if R and B is closed without a call for heat. Make sure the t-stat is set up for heat pump, B energized for heating, no aux heat. 
    I'd really like to know what you find. 
  • Illinoisfarmer
    Illinoisfarmer Member Posts: 17
    edited January 2021
    Not sure if this helps, but I'm bored so here goes. 5 ton, 2 stage GSHP. Robertshaw Thermostat.

    No Call, Stat set to heat: R25v; Br2v; O,Y1Y2,G,W all 0 volts
    Heat Stage 1: R,Y1,G all 25v; Br2v; O,Y2,W all 0 volts
    Heat Stage 2: R,Y1,Y2,G all 25v; Br2v; O,W 0 volts

    Cool Stage 1: R,Y1,O,G all 25v; Br2v, Y2, W 0 volts.

    I quit trying at that point. I can check something else if you want.

    Interestingly, when testing Cool Stage 1, there was a sudden, loud whining noise from the second floor of the house. Upon investigation, I discovered that son #2 had his blanket routed over one of the heat vents while he played video games. He was not prepared for the blast of air conditioning apparently, and was somewhat startled, and a bit of a wimp about his now cold bare feet.

    Have a good New Year!
  • AMservices
    AMservices Member Posts: 601

    Not sure if this helps, but I'm bored so here goes. 5 ton, 2 stage GSHP. Robertshaw Thermostat.

    No Call, Stat set to heat: R25v; Br2v; O,Y1Y2,G,W all 0 volts
    Heat Stage 1: R,Y1,G all 25v; Br2v; O,Y2,W all 0 volts
    Heat Stage 2: R,Y1,Y2,G all 25v; Br2v; O,W 0 volts

    Cool Stage 1: R,Y1,O,G all 25v; Br2v, Y2, W 0 volts.

    I quit trying at that point. I can check something else if you want.

    Interestingly, when testing Cool Stage 1, there was a sudden, loud whining noise from the second floor of the house. Upon investigation, I discovered that son #2 had his blanket routed over one of the heat vents while he played video games. He was not prepared for the blast of air conditioning apparently, and was somewhat startled, and a bit of a wimp about his now cold bare feet.

    Have a good New Year!

    Thanks for checking. All that makes sense.
    The difference with your system and the one I was working on is your RV is cooling energized.
    Can you see what readings you get with the t-stat set to cooling, no call, and tell me if the RV has power? That would be comparable to my nightmare.
  • Illinoisfarmer
    Illinoisfarmer Member Posts: 17
    Not a problem. Stat set to cool, setpoint at 72. Reading 70, no call for cool.

    R,O 25v; Br2v; Y1,Y2,W,G all 0v.

    Shortly after I switch the mode from 'auto' to 'cool', I hear a faint click from the stat. I'd bet that is the RV energizing. Good luck.
  • AMservices
    AMservices Member Posts: 601
    Thank you for confirming what I was finding.
    In conclusion, a thermostat will hold a reversing valve in the position needed for heating or cooling.
    I don't know why that bothers me so much. I suspect it's so the RV doesn't change over every time and would require a 5 minute delay any time there was a call for it to change over.

    @Illinoisfarmer you are a heating helper
  • GW
    GW Member Posts: 4,429
    I got jammed twice by the T6 last year on heat pumps. I have moved on. I enjoy the Ecobee, super easy setup. 

    Silly question but did you make a heat call by simply jumping wires? My brain would be unsettled until I felt some heat blowing. 
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • AMservices
    AMservices Member Posts: 601
    No jumping. This was all a function of the 5 thermostats I tested.
    Heat worked.
  • ratio
    ratio Member Posts: 3,046
    GW said:

    I got jammed twice by the T6 last year on heat pumps. I have moved on. I enjoy the Ecobee, super easy setup.

    @GW, can you share the problems you were having with the T6? We install them from time to time, I'd like to know if I need to watch for anything specific.
  • GW
    GW Member Posts: 4,429
    @ratio I recall it had something to do with the thermostat not sending adequate power to the reversing valve. I think we were getting about 14 V or so. I was told that there was some issue/recall. We replaced them and all was fine. I never actually received any notice on this; bugged me a little. 

    And I got tired or running wires to the north (dual fuel). As you probably know, sometimes it’s a pain getting wires a certain sides of the house.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • GW
    GW Member Posts: 4,429
    Coincidently, we did a quick heat pump AHU change out this past summer. Modern Honeywell 8000 series installed by previous hvac guy. A couple months later the homeowner calls us and says the electricity bills are out of sight. We go check it out, heat strips were firing on AC call. How the thermostat reverted to kicking on emergency heat while AC was calling, it’s still a mystery to this day. My guy grabs a brand new thermostat out of the truck, same 8000 series, guess what, same exact problem. My guy puts the original 8000 back on the wall, digs through the manual, makes some parameter change, everything goes back to normal. I was the most loyal Honeywell thermostat installer there has ever been. Installed hundreds.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • ratio
    ratio Member Posts: 3,046
    Wow. I've never really understood all the different names that are used for the various heat sources used in a heat pump, or the fact that most things on thermostats are named for what they're used for, vs what that actually do. "Gas/Electric" vs "fan on with heat call" drives me crazy. Seems to me that if they just said what everything did, we'd have an easier time of it all around.
  • GW
    GW Member Posts: 4,429
    I'm not a grizzled HP tech either (1980s plumber turned hvac guy), just know enough to keep our hp systems running normally! The switch on the stats simply makes the fan come on during a call- or not. AHUs often need the fan to come on (controlled by the stat), whereas a furnace generally kicks the fan on via timer/ control board.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • ratio
    ratio Member Posts: 3,046
    Right. We manage to get stuck with frankensystems that need the fan call with heat often enough that I'm worried about people swapping out the carefully programmed thermostat without understanding why it's programmed the way it is.
    GW