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Boiler Piping question



In this picture I am asking about the flow of water from the boiler through the baseboard and back to the boiler. Does the circulator push the water through the baseboard, or does the circulator suck the water back into the burner?

Can you identify the two pipes for me?

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    edited March 4

    The circulator does not actually push or pull. It creates a difference in pressure. think of it like a bicycle chain. When one link moves they all move. So the pushing, if you want to call it that, is at the outlet of the pump and the pulling is at the inlet of the pump.

    You might get the impression that the water gets compressed on the discharge side of the pump and the water somehow gets stretched at the inlet. Water can not be compressed. It can make hydraulic pressure that can actually move things mechanically but a circulator pump is the wrong kind of pump for that operation. And water is not the best fluid for hydraulics.

    This division of physics is called Hydronics. And it has more to do with moving heat from one place to another and less to do with moving objects like front end loader buckets, or lifting cars at a mechanics shop.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99
  • Jamie Hall
    Jamie Hall Member Posts: 23,272
    If you have the two pipes labelled correctly, it looks like the circulator is pulling on the return.

    Which is probably the worst possible plumbing arrangement you could have...

    But you can double check pretty easily. Which pipe is hotter? That's the supply.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    docbar99
  • docbar99
    docbar99 Member Posts: 31
    Thank you both @EdTheHeaterMan and @Jamie Hall Hall. You both answered a question that I was not sure of.

    1- Since I keep my thermostat at 63 I am concerned that the returning water might be too cool and would want to place my temperature probe in a place that can detect that condition . I have learned on this forum about how a low temperature return can lead to condensation. Should my temperature probe be placed under or over the circulator to see if there is a likelihood of compensation?

    2- To Jamie's point, I did see in Boiler manual that the circulator should be on the supply side instead of the return side. What kind of issue can reversing this cause?



    3- Should I report this as an issue to the contractor that installed the system? If so, what is the technical reason ?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    edited March 4
    BOILERS
    You may want to read this post I made just the other day
    https://forum.heatinghelp.com/discussion/comment/1793949#Comment_1793949

    There are several other problems, The Air Separator or Air Scoop is not installed according to the manufacturer's instructions. It will be less effective as it is currently installed. And there is a dangerous condition with the hot water piping from the coil to the spigots and faucets. Water as hot as 180°F can be sent to a tap and a person washing their hands can get scalded. A mixing valve must be installed for that reason. It is also in the installation manual for that boiler.

    If the paperwork for purchasing your new boiler included any type of wording that resembles “installed according to the manufacturer’s instructions” then your contract was not fulfilled and you have grounds for the installer to complete the job correctly. Even if your contract does not say those words, many States have laws that make those words a part of any contract even if they are not specifically written in the document.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99Intplm.Alan (California Radiant) Forbes
  • Jamie Hall
    Jamie Hall Member Posts: 23,272
    The question isn't whether the circulator is on the supply side or the return side. The question is -- where is it in relation to the expansion tank? For goo results, the expansion tank -- and autofill pressure reducing valve and all that -- should be upstream from -- that is, on the suction side -- of the circulator. Nothing except some pipe -- and not all that much of that -- in between.

    And that is worth getting someone in to fix.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    On page 7 of the manual for your boiler (I believe you have a Peerless WBV) is this diagram of how to connect the hot and cold water pipes top your tankless coil.
    Now I have talked to professional plumbers that did not understand that the water in the coil can be as hot as 180° to 200°F. And when someone turns on a water tap, that extremely hot water will come out that tap. If your installer is that type of professional, then I would request that he do a test where he leave his hand in the hot water stream as the water comes from the hot tap. Then when he removes his hand from the scalding hot water, ask him to install the mixing valve.His response might be to lower the boiler temperature on the control. When he does that, then run the hot water for 10 minutes. "Only Hot". Then in 10 minutes after the boiler temperature drop to the new lower temperature setting, ask him to feel the hot water and see if it is hot enough to take a shower. It won't be. Then ask him to install the mixing valve.

    When the water is moving thru the coil, it will not get as hot as the boiler water. but when it is turned off, it will get to be the same temperature as the boiler and that is the problem. That is why you need an automatic mixing valve. This is the Boiler Manual where I found the illustration on page 7. https://www.peerlessboilers.com/wp-content/uploads/2017/08/PP8046-WBV-R39_IOM_web0622.pdf

    The Air scoop is not installed according the the manufacturer's instructions, and the manufacturer's instructions also show the circulator in the proper location on the supply pipe. Here is the illustration that shows at least 18" of strait pipe going into the air scoop.


    Here is the instructions sheet: https://www.tacocomfort.com/documents/FileLibrary/101-007.pdf
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99STEAM DOCTORSuperTechLong Beach Ed
  • hot_rod
    hot_rod Member Posts: 22,105

    On page 7 of the manual for your boiler (I believe you have a Peerless WBV) is this diagram of how to connect the hot and cold water pipes top your tankless coil.
    Now I have talked to professional plumbers that did not understand that the water in the coil can be as hot as 180° to 200°F. And when someone turns on a water tap, that extremely hot water will come out that tap. If your installer is that type of professional, then I would request that he do a test where he leave his hand in the hot water stream as the water comes from the hot tap. Then when he removes his hand from the scalding hot water, ask him to install the mixing valve.His response might be to lower the boiler temperature on the control. When he does that, then run the hot water for 10 minutes. "Only Hot". Then in 10 minutes after the boiler temperature drop to the new lower temperature setting, ask him to feel the hot water and see if it is hot enough to take a shower. It won't be. Then ask him to install the mixing valve.

    When the water is moving thru the coil, it will not get as hot as the boiler water. but when it is turned off, it will get to be the same temperature as the boiler and that is the problem. That is why you need an automatic mixing valve. This is the Boiler Manual where I found the illustration on page 7. https://www.peerlessboilers.com/wp-content/uploads/2017/08/PP8046-WBV-R39_IOM_web0622.pdf

    The Air scoop is not installed according the the manufacturer's instructions, and the manufacturer's instructions also show the circulator in the proper location on the supply pipe. Here is the illustration that shows at least 18" of strait pipe going into the air scoop.


    Here is the instructions sheet: https://www.tacocomfort.com/documents/FileLibrary/101-007.pdf

    That is an unusual piping configuration on that mixing valve where the hot goes into the tee.
    Usually H and C are across from one another, mix out the tee.

    Here is an excellent valve for tankless, fast responding, fails safe if cold drops off, and a straight through angle pattern makes piping simple.

    8 fps max. Velocity in that scoop purger, good luck with that even if you can find a piping material to handle hot water at that speed
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Intplm.docbar99
  • docbar99
    docbar99 Member Posts: 31
    @EdTheHeaterMan and @Jamie Hall - You guys have been so helpful, I can't thank you enough. I will report this to the contractor and see if he will fix some of these issues. I understand about the location of the circulator and the mixing valve, but I am not sure I can explain the issue with the location of the taco air scoop and the need for 18" of strait pipe. I see it on the diagram, but not sure how to explain the need for 18" of strait pipe.

    Can you explain that one a little more to me about the 18" ?

    I read your article from the link. It is a little too advanced for me, but I will study it and eventually understand it. What I did get from it (I think) is that if the circulator is not placed in the right spot, you wind up with more air in the baseboards and more water in the expansion tank, both unwanted.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    @hot_rod said
    That is an unusual piping configuration on that mixing valve where the hot goes into the tee.
    Usually H and C are across from one another, mix out the tee.


    i agree, unusual configuration... that is an illustration from the Peerless I/O manual that I marked up. I didn't really look that closely. I just looked at the photograph @docbar99 posted and did not see the required valve. If the installers of these things only would read the instructions and learn about the hazards of what they omit. The world would be a better place.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99
  • Intplm.
    Intplm. Member Posts: 1,937
    docbar99 said:

    @EdTheHeaterMan and @Jamie Hall - You guys have been so helpful, I can't thank you enough. I will report this to the contractor and see if he will fix some of these issues. I understand about the location of the circulator and the mixing valve, but I am not sure I can explain the issue with the location of the taco air scoop and the need for 18" of strait pipe. I see it on the diagram, but not sure how to explain the need for 18" of strait pipe.

    Can you explain that one a little more to me about the 18" ?

    I read your article from the link. It is a little too advanced for me, but I will study it and eventually understand it. What I did get from it (I think) is that if the circulator is not placed in the right spot, you wind up with more air in the baseboards and more water in the expansion tank, both unwanted.

    The air scoop needs at least 18" of full pipe diameter entering it as water will, in theory, roll through the pipe leaving air space on the top of that length of 18" of pipe. This allows air to escape from the system as it flows from the supply side of the boiler.
    This is also old technology and not the best way to remove air. I have stopped using air scoops and will only install micro bubble air separators on all hot water boiler installations.
    If you can get one installed rather then the air scoop you have now it will be a much better functioning system.


    This is an example ( below ) of a Spirovent brand micro bubble air separator. There are other brands that work as well.

    If you go to the trouble of having your system taken apart, I would use one of these and also have the makeup water fed at the point of no pressure change.





















    SuperTechdocbar99
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    docbar99 said:

    @EdTheHeaterMan and @Jamie Hall - You guys have been so helpful, I can't thank you enough. I will report this to the contractor and see if he will fix some of these issues. I understand about the location of the circulator and the mixing valve, but I am not sure I can explain the issue with the location of the taco air scoop and the need for 18" of strait pipe. I see it on the diagram, but not sure how to explain the need for 18" of strait pipe.

    Can you explain that one a little more to me about the 18" ?

    I read your article from the link. It is a little too advanced for me, but I will study it and eventually understand it. What I did get from it (I think) is that if the circulator is not placed in the right spot, you wind up with more air in the baseboards and more water in the expansion tank, both unwanted.


    Basically it is the difference between laminar flow and turbulent flow, but I do not believe that you need to know why, the only thing you need to know is that "because it says so" in the instructions, and the installer didn't follow the instructions.


    That being said, I agree with @Intplm. regarding the air scoop being old technology. however you probably don't get a choice in this part of the process. Your contract probably does not specify a "Micro-bubble air separator" so you can't ask for the one you have, to be replaced with a more expensive device. What you can ask for is the part supplied to be installed properly according to the instructions.


    As far as how the part works, Micro bubbles of air are not as buoyant as larger bubbles of air. That means that smaller bubbles will take more time to float to the top of the pipe. If there is a turn or baffle in the approaching pipe, the air bubbles will get agitated by the obstruction or change in direction causing turbulent flow. That will allow a large portion of the air bubbles to find their way to the bottom of the pipe. If there is a 90° elbow within a few inches of the air scoop, then that air near the bottom of the pipe will not be directed to the top of the scoop. By having 18” of approach piping, you will have what is known as laminar flow inside the pipe. All that means is the water at the top stays at the top, the water in the middle stays in the middle and the water at the bottom stays at the bottom.

    This laminar flow allows the lighter air bubbles to rise to the top of the pipe. When the air at the top of the pipe enters the scoop it will go in the top chamber above the internal baffle and be directed to the air vent at the top of the scoop. A good plumber will understand that. A parts changer may not, and just use the parts because that is how he was told to do it by his boss, when first started doing this work. I remember making that mistake many years ago.


    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99Intplm.SuperTech
  • docbar99
    docbar99 Member Posts: 31
    @EdTheHeaterMan- Thanks for your thoughtful and precise answers. You really know the science behind the scene that makes these things work. The crew that installed this burner knew how to solder pipes together but did not know how to configure the Hydrostat or answer questions properly. The boss never came to the house, and he takes weeks to answer an email. I think they just tried to copy the existing system without an understanding of basic principles or realizing that the system they replaced was 50 years old. I am going to ask that they make the corrections according the the WBV manual and the air scoop documentation.

    Do you think it is unreasonable to ask him to move the circulator to the supply side?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    edited March 6
    It is not unreasonable. It is the way it is pictured in the I/O manual for the boiler and it is in the documentation for the Air Scoop. Who are they to go against the manufacturer's instructions/ recommendations, and basic science?

    I would ask them to look closely at the manual. And if they are slow at getting back to you, Let me tell you that a Certified Letter from the United States Postal Service will get their attention. and send a copy to the licensing board in your state. It is proof that you want a reply and will be great in court if you ever need it. I can help you craft the letter if you Priv. Msg. me.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99MikeAmann
  • docbar99
    docbar99 Member Posts: 31
    @EdTheHeaterMan- Thanks again Ed, your support has been incredible. One one hand I don't want to keep bothering you with all my basic level questions, but on the other hand I feel that you love this industry and like to share your knowledge. I am trying to digest all the great information that you have given and write a report to send to the contractor. If you don't mind I will email you a copy to see if you agree with what I wrote.
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    I will be happy to review your letter. You should include this diagram with it.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99
  • docbar99
    docbar99 Member Posts: 31
    That is awesome. I really appreciate it
  • docbar99
    docbar99 Member Posts: 31
    @EdTheHeaterMan - Hi Ed I sent you the the letter to review in your email. Thanks again.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,818
    Your letter looks fine. I believe you should send it by certified mail with a return receipt. You will probably get a phone call the day the letter is delivered.


    Hopefully this will get you in a better place with a lower oil bill.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    docbar99
  • docbar99
    docbar99 Member Posts: 31
    @EdTheHeaterMan- Well the crew came today, but I could not be there due to work commitments, and they did the job, but not as you said.


    When I got home they were still there and had just packed up the truck. I asked him about the combustion anaylsis and they said they did not know anything about that, I should call the office.

    They totally missed the point about the 18" of strait pipe, and put the air scoop between 2 elbows. This is like a clown show, this the 4th time they were here.


    delcrossvSuperTech