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bypass valve woes

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by shoeboxlen, Oct 20, 2013.

  1. shoeboxlen

    shoeboxlen Member

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    I think my danfoss bypass valve has taken a dirt nap on me it seems like the heated water is not making it over to the heating system and just keeps circulating in the boiler. can I replace the guts of it or do I need to buy a whole new unit. I have pictures of the front and back side of it any help would be greatly appreciated the sooner I get the wood boiler repaired the better. thanks in advance for your help.

    Len

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  2. shoeboxlen

    shoeboxlen Member

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    a suitable replacement recommendation would also be most welcome been searching all nite and I cannot even find the one I have let alone parts for it.
  3. Fred61

    Fred61 Minister of Fire

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    I assume it has been working fine since you installed it and I assume you haven't removed it or have not done any re-plumbing in that area. The thermostat is just an automotive wax bulb gadget that is manufactured to actuate at a specific temperature.

    The first thing I would do is remove it and test it in a pot of water heated to the value of the unit, typically 140 degrees F. If it fails I would try to find a phone number or email address for the company first and if you have no luck at that you could try to match it up with one from an automotive parts store. I believe only two parameters need to match and those would be the diameter of the large flange that seats on the mounting surface and the temperature value. It may be difficult to find one down to 140 in an auto store but 160 is acceptable and used by many on their boilers.
  4. stee6043

    stee6043 Minister of Fire

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  5. shoeboxlen

    shoeboxlen Member

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    thanks guys I ordered the one from pex. I will replace it with that one for now but take the bad one to the auto store and see if i can match it up so I have a spare just in case. I searched using the numbers on the casting to no avail found some replacement ones but was unable to finde a proper seller. will be bookmarking the pexsupply.com address for sure. thanks again for saveing my behind on this.

    Len
  6. shoeboxlen

    shoeboxlen Member

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    well I got the part in today. it was actually just the small center piece of the thermostat so I had to disassemble the thermostat and put it in the center. btw not an easy job. was not expecting there to be so much presure behind the cover of the housing so I got a pretty good bath. I put it all together and reassembled it used rtv on the cover as the paper gasket was not looking to good after I took it apart so I am now just waiting for that to cure before I fire everything up. crossing my fingers it will do the trick. will let ya know if I got heat again real soon I hope. thanks again. to everyone.

    Len
  7. woodsmaster

    woodsmaster Minister of Fire

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    You can buy sheets of gasket at the automotive store and cut out your own gasket.
  8. shoeboxlen

    shoeboxlen Member

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    that did not work out at all the boiler overheated used a laser thermometer and it looked like the water was going where it should but it was not reaching the zones for some unknown reason. I am calling in an expert at this point reached e3 on the controller. so I had to shovel out the burning logs luckily there was not much left but enough to make a mess and a lot of smoke. water in a wheel barrow to kill the flames and we are all good but man I am a little downhearted at this point. oh well I guess we all cant be hvac guys.
  9. mr.fixit

    mr.fixit Member

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    Is it possible that your bypass/balance valve inadvertently was closed down to far?
  10. maple1

    maple1 Minister of Fire

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    If it's not getting to the zones then it's not going where it should - so there's still some detective work to do. Not sure what we can do to help since we don't know anything about your system and aren't there - but you (or someone) should be able to find the problem by heat-tracing all your plumbing while things are up to temp & loads are calling. Could be a circ gone bad or stuck, could be an airlock, could be a bad or stuck stuck zone valve, could be a few things.

    Smaller fire next time maybe? _g
  11. shoeboxlen

    shoeboxlen Member

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    I made a video of the configuration on the piping. it is here http://corp.parsonscenter.org/stuff/boiler.mp4 (work website) any chance you guys can take a peak at the piping and tell me where I am going wrong here. I picked up a replacement circulator just in case. my uncle is a plummer and he says the circulator is backward it should be pushing the hot watter towards the oil boiler no the wood boiler. I keep looking at it and I don't se how that should be the case the return water coming in the top of the boiler seems kinda backwards to me but hopefully you guys can make sense of it. any help would be greatly appreciated.
    Last edited: Oct 24, 2013
  12. maple1

    maple1 Minister of Fire

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    Is this a new setup?

    Or is it one that worked right at one time, but now doesn't?
  13. rkusek

    rkusek Minister of Fire

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    I didn't see one on the video but do you have a Y-strainer somewhere that could be plugged. I had a similar problem on startup last season where the boiler was going into idle not getting hot water to the system. I hadn't checked it for a couple years and it was plugged good. Funny thing is the system worked fine until it was shut down the previous spring.
    ewdudley likes this.
  14. Fred61

    Fred61 Minister of Fire

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    It appears that you have your Danfoss on the output of the boiler. I know that the instructions say that it may be installed on the output or input but I don't know what problems can arise if something goes haywire. I also noticed that the ball valve in the bypass is wide open for what it's worth.
    Also:
    Is there a way you can purge your zones to see if you can push out a bubble?
  15. shoeboxlen

    shoeboxlen Member

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    put a new preasure relief falve on as mine started leaking when I used it to purge air. also put a new auto bleeder on so hopefully I wont need to do that again. the danfos has a new thermo stat sensor in it. the system has been working for years with no issues. I put a new circulator on it as the one I put on was labeled as good but when I pulled it I could not turn the impeller with a screwdriver on a fin. so I figured may as well put a fresh one in as well. so all parts on boiler side are new at this point. firing now hope I can get a working boiler tonight.
  16. shoeboxlen

    shoeboxlen Member

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    Fred61, yes the bypass is wide open I tried closing it half way to see if that would force water through the thermostatic. but I have it back to wide open as that is the way it was should it be partially closed off or something? SO far so good the thermostatic valve popped open and the temp of the boiler dropped right away so I think I had a bad thermostat then put a bad circulator on and compounded my issue.

    boiler went to temp jacked the thermostat in my basement which uses a circulator and old iron radiators which I use for a heat dump in case the boiler gets too hot and it worked as it should so I am officially back in business! thank you again guys. but I am still interested about the valve thing on the bypass line.
  17. maple1

    maple1 Minister of Fire

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    The valve thing in the bypass line is a thing that has always puzzled me. Having had no direct experience with a Danfoss, I have just ignored it. If it is there, there is no sense in leaving it open all the time - or else there is no sense in having it there. Right? And seems to me that having to have it there to use is just a make-shift fix for a design flaw in the operation of the Danfoss. Having said all that, I think there is a newer (relaltively), or later version of the Danfoss, that works as one would expect & wouldn't need a bypass valve.

    But someone with direct experience should jump in & clarify....
  18. woodsmaster

    woodsmaster Minister of Fire

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    I leave the valve on mine slightly closed and never touch it. I agree it shouldn't need a valve on it, but I didn't have the extra money for one of those fancy loading valves so I went with the danfoss and it works fine so far.
  19. Fred61

    Fred61 Minister of Fire

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    Only a small amount of flow is needed through the bypass to actuate the thermostat. That being said, a little more flow will help keep the thermostat open for a longer period of time as it will mix the warmer recirculating boiler with the colder water coming from the system. I suggest you start with 50% open and adjust from there over time. No hurry, don't over compensate. I found my "sweet spot" 5 years ago and haven't adjusted it since. Full open in not the right place to be.

    I understand they have emerged from the dark ages technically and now have a unit that works without the need to throttle the bypass flow.
  20. B-Mod

    B-Mod Member

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    What is a better thermo boiler protection valve than the danfoss? Caleffi?
  21. rkusek

    rkusek Minister of Fire

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    +1 on what Fred said. Start at 1/2 way and adjust from there. I think mine might be 2/3 closed, definitely don't want wide open. The laddermat loading valves and the new style danfoss valves don't need this. But since you already have this one, I wouldn't change it, but the new one is definitely the way it should have been designed in the first place.
  22. shoeboxlen

    shoeboxlen Member

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    thanks guys I have set mine to halfway closed now I guess I have had it wrong for years as I have always left it wide open. thanks for clarifying. sure feels good to have the house nice and warm. the wife likes the house a at least 73 degrees and with fuel oil that gets expensive. thank god for the eko or I would be toast with fuel bills being what they are.
  23. maple1

    maple1 Minister of Fire

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    There's a ton of different techniques & equipment used on here, but the end purpose is the same - take FULL control of your fuel supply, and enjoy the results. Oil is a very good thing to get off of.
  24. shoeboxlen

    shoeboxlen Member

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    Second week and all is running perfectly thanks again for everyone's help
  25. Fred61

    Fred61 Minister of Fire

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    You're welcome. Now that you have a pretty good idea as to what's going on with your Danfoss you can start experimenting with the flow through your bypass. Remember, if your bypass is the route of least resistance, your flow will just circulate within the boiler through the bypass and the flow through your zones will be diminished. Could cause more idling and lower efficiency.

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