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Excuse the lack of knowledge...is this a 3-way mixing valve?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Gilby, Oct 26, 2012.

  1. Gilby

    Gilby Member

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    Hey guys! Tis the season! Random question...throughout some issues last winter, you all gave one consistent piece of advice...and that was protection in the way of a 3 way mixing valve. I purchased one a couple weeks back, but haven't installed it yet. As I fired up the Orlan 60 for the first time this season, I noticed something I hadn't paid much attention to before....

    I've included three photos to look at. I've circled what I thought might be the mixing valve. The bottom arrow is the return to the back of the boiler. I choked that ball valve up above to send more water to the pumps. If I open it all the way up, it seems as though the water flows right by the pumps and I don't get much to them. If I choke it down, I had much more hot water flowing directly to the two pumps.

    Any thoughts?

    Attached Files:

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  2. Fred61

    Fred61 Minister of Fire

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    I think what I'm seeing in the photo is a Danfoss boiler protection unit. Although it does mix boiler supply with return water, it's usually not referred to as a three way mixing valve. Is it on the return line to your boiler? In what context are you trying to identify a three way mixing valve?
  3. Medman

    Medman Feeling the Heat

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    It is indeed a Danfoss or three way mixing valve. It is unfortunate that it is installed with the access port toward the wall, because it looks like it would be hard to change the thermostatic element inside if needed. My Danfoss came from the factory with the element installed in the wrong direction! I did a lot of headscratching and asking questions here before I figured it out and reversed the element. You may have the same issue.
    I also have the ball valve choked down to a fairly low flow, as you do.
  4. Bob Rohr

    Bob Rohr Minister of Fire

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    Do you have some way of measuring temperature leaving the boiler supply, at the return to the boiler, return from the system? You can feel the pipes carefully with a bare hand to see where the flow is going, and get a general idea. Do youhave access to the cover onn the 3 way?

    Really you should not need a valve on the bypass, it's trying to force the 3 way to do something it was not designed to do. If the valve is the correct temperature 130- 140F, assembled and installed properly, it has a fairly simple task, bypass all the flow back to the boiler on cold start, slowly allow flow to the system. When the return to the boiler is at the valve setting, plus some differential, then the bypass should be 100% off.

    Different valve brands have different accuracy, only with some temperature gauges, strap on thermometers, or a point and shoot temperature gun, will you know what is going on.

    Attached Files:

  5. Gilby

    Gilby Member

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    What's unfortunate is I just spent $200 on a brand new one that I don't need!! Hopefully I can send that back. It is on the return line to the boiler. I have a plumber booked to come rework my system and everyone here said I needed the return protection...so I purchased the 3 way. As I fired it up last night and was adjusting valves, I stood there and stared at the whole loop. Not knowing anything last year, I wouldn't have had a clue. Knowing a wee bit more this year, some more things made sense last night that hadn't clicked before.


    What about the valves? I have the one leading down to the danfoss almost closed off and it seemed to send more hot water to the pumps. Is there any potential problems with that hot water still circulating past the pumps even when the furnace isn't calling for heat? If I open that valve all the way up, it appears that water just flows right by the pumps and goes back to the boiler. When I choked it down it seemed to function better and increased the hot water running through the pumps. Just not sure if it's hard on the pumps or anything else....
  6. Gilby

    Gilby Member

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    I don't have a specific way, no, but would be open to suggestions. One of my biggest issues is the cold start. Firing it up last night for the first time on a chilly evening always poses big issues. I started it at six...and by the time it was functioning and doing what it was supposed to...and my house was warm...it was 10 oclock. And I hadn't sat down or stopped fiddling with it the entire 4 hours. I can get the water temp up and circulating at 175...but as soon as any amount of air from my furnace blows on the coils, the water temp drops to 140-145 rapidly. Throughout this process, my pumps shut off randomly on their own. My furnace will be running, but I'll go check my pumps and they won't be circulating...all the while the water temp is climbing. I'll slide my controller up or down and you'll hear those pumps kick back on. Makes me wonder if I dont have an issue with my controller...but still doesn't help with my return water being so cold.
  7. Gilby

    Gilby Member

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    Just another thought...I purchased a Danfoss 3 way thermostatic valve from New Horizon.....should I keep it and use it? Or stick with what I have and get my $200 back?
  8. stee6043

    stee6043 Minister of Fire

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    I'll agree with the above that this looks like it might be the backside of a Danfoss brand mixing valve. If you paid to have that installed when your system was put in I'd recommend you call your plumber and have them come out and do it right. Installing that thing with the access panel facing a wall is just plain silly.

    Like Medman said there was a rash of Danfoss valves not too long ago with the stickers and/or guts installed incorrectly which made it nearly impossible to heat correctly with them installed in the "directed" fashion. It's easily fixed but you have to be able to pull the plate off and get to the thermostat inside.
  9. stee6043

    stee6043 Minister of Fire

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    Have you compared the back side of the Danfoss you bought to the unit circled in the photo? Grab a mirror and see if you can see what the sticker on the front of the valve says (the circled valve in your photo). It should have a sticker with directions/arrows on it. Although, that being said my sticker did fall off after year 3 or 4 I think...
  10. Gilby

    Gilby Member

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    I did not pay to have that one installed - I bought the house and the boiler pretty much sits as it came. The previous owner did all sorts of jacked up stuff to it when he installed it. The mixing valve is par for the course if it is installed backwards. Would it beign backwards have any adverse affect on how it functions??
  11. stee6043

    stee6043 Minister of Fire

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    The actual orientation of the valve is of no consequence, other than servicability. The problem is that you cannot tell if the valve is properly installed in terms of supply vs bypass orientation. The three ports on that valve are not interchangable. But they can be manipulated/corrected if you can access the thermostat inside (which you cannot, currently, because of it being installed facing the wall).
  12. Medman

    Medman Feeling the Heat

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    The element inside can go in two of the three port positions. It looks like you can change yours around, if you can get at it. Your description of the operation of your system is familiar - almost exactly the same problems I had at first, with the element installed in the wrong direction. If you can get at the cover, the label might look correct (as mine did) but the element inside may be reversed.
  13. Gilby

    Gilby Member

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    So do you suppose at any point those pumps shutting off on their own is related to the controller since the only way I get them to kick back on is to slide/jiggle the controller up or down? Seems far fetched that my mixing valve might be screwing with my pumps, no?
  14. Fred61

    Fred61 Minister of Fire

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    Here I am, again being a contration. The only way the Danfoss will work correctly is if the automotive thermostat sensing bulb is toward the boiler. This allows it to sense the circulating temperature. If it were turned around and the sensing bulb was on the side of the returning water from the system it wouldn't be able to flow. I got alot of experience when installing my system as I was one of those that got one that was assembled backward. Look in the center bore and you should be able to see the sensing bulb. That bulb should be oriented toward the boiler. If you don't see the bulb, it is assembled backwards and water from supply will not activate thermostat.
  15. JP11

    JP11 Minister of Fire

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    The only way I can even THINK of the two being related is if they were new, high tech, temp sensing pumps.. but I'd bet that's not the case.

    Good Intel is what you need. What's happening at what time and what temp. Temps in many points will help.

    If you can provide good raw data.. labeled pictures and/or a nicely drawn schematic WILL get you the answers to fix your system here.

    There's lots of guys on here that have screwed up in every way imaginable. There's some pros on here two that are very generous with their expertise.

    JP
  16. mr.fixit

    mr.fixit Member

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    Seems to me when you posted with problems last time there was some odd plumbing with your system?
    You might want to post bigger view pics so everyone can see the complete plumbing system if possible.
    Or draw up a diagram.
    On the 3 way,the pic looks like my danfoss,backside.Mine is facing that way also but I mounted it closer to the boiler so you can access it.
    The pumps (other than the boiler loop)may be connected to a aquastat or temp controller to turn the furnace fan on and off so the fan doesn't run if the water isn't hot enough.
    The controller should be controlling the pump on boiler loop.
  17. Gilby

    Gilby Member

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    My furnace will continue to run in the house blowing cold air becuase the pumps shut off and there is no hot water circulating to my furnace coils. Once I shift the entire controller, the pumps kick back on. Random. It's like a wire is loose. BUT once the house is up to temp and all the water is warm enough, the pumps never have an issue. Only on a cold start.

    It is plumbed funny, I think. I have no way of knowing other than you guys telling me so. The worst part is without someone here looking at what I have, no one has been able to tell me what is exactly wrong. The plumber is set to come out next week...but he says it'll be a full days work at $78 an hour. I really, really don't want to spend a $1000 to have him rework something he's not even sure about only to have the same results.

    Here is what I had posted last winter. More pics and what I think is the direction of flow, etc. The little diamond is where the mixing valve is...with a ball valve above it. When I choke that upper valve, I seem to get more hot water to my pumps...but that doesn't solve the problem of them shutting down on their own....

    http://www.hearth.com/talk/threads/...no-hot-water-to-the-coils.80708/#post-1031107
  18. Morgan

    Morgan Member

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    $78 an hour!, I am living in the wrong area :) , hell, I would help you for a lot less if I was anywhere near Wyoming
  19. mr.fixit

    mr.fixit Member

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    As Heaterman pointed out in that past thread you linked to,your plumbing is a combination primary-secondary and manifold systems.Funny it works at all. I would say you need a shut-off valve(or a section taken out and plugged) installed in the vertical pipe just to the right of the 2 pumps(to work as a manifold system).Maybe someone else can try to study out your plumbing and see what they think.

    Where do the 2 red pex lines that go thru the sill board towards the rear of the boiler go?Overheat loop?

    If moving the controller around makes the pump go on or off sounds like you have a loose wire.
    You can pull the controller out and check the connections but first disconnect the power.
  20. I'd say tear out all the piping and start over. Give your plumber a diagram of a proven design and tell him that's what you want.

    You'll be money ahead by doing it all over instead of trying to fix up that mess.
    JP11 likes this.
  21. Bob Rohr

    Bob Rohr Minister of Fire

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    I'll second that, time for a sawzall level repipe. Something about lipstick and a pig...
  22. BoilerMan

    BoilerMan Minister of Fire

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    It's interesting the stuff we see that's "kinda right" looks like the PO had acess to some contractor-grade fittings and components, but totally failed to installe them in the right order or level and straight for that matter. Always "pump away" I think this is even more true in an almost boiling wood hydronic system. Hotter water can flash boil at the lower pressures that pumping toward the tank can create.....then we get cavitation and air locks, making the whole thing stop moving heat, or make it work intermittently.

    TS
  23. Gilby

    Gilby Member

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    I am all for repiping to make it right.... But I'm not sure where to get a diagram of a correct version?! Can anyone point me to one? I've had guys say "look at so and so's" but a different room with different components is hard to match.
  24. mr.fixit

    mr.fixit Member

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    It appears to me Gilby that your setup is plumbed very close to that diagram that Mike linked to,with one exception.
    It doesn't look like you have the check valve between the zone pumps supply and returns.
    It would prevent the zone pumps from recirculating their own return flow.

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