Boiler and tank on 1/2" copper

Discussion in 'Boiler Forum' started by wallygater, Feb 13, 2010.

  1. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    I would like to re-pipe my current boiler setup from 1/2 to 3/4. The supply from the meter is 3/4 copper pipe. For some reason it was reduced to 1/2 for everything in the house including the feed to the boiler. I would like to re-pipe the system so that the boiler will be fed by 3/4. Attached to my boiler is a hot water holding tank. In between the two is a circulating pump. All of this is currently piped in i/2 copper.

    My goal is to feed the brand new high flow shower with 3/4 copper.
    the cold was easy, all I had to do was tee off the main and run a dedicated line to the shower mixing valve.
    The hot is obviously more difficult
    So far I have been able to run a dedicated 3/4" hot feed from the top of the hot water tank to that shower mixing valve
    My problem is the boiler and hot water tank is all fed by 1/2". This is what I would like to correct
    The pictures show the boiler and circulating pump and tank
    the pump is a little giant model # CMD-1003B
    The hot water tank a Rheem model # 666H-300
    I think I will need a different pump because this one only has 1/2" connections. Or does the pump matter?
    The boiler is no problem, there are 3/4" connections that can be utilized on that
    The hot water tank has 3/4" connections on the top, but the bottom nipple where the pump is connected is 1/2". Does this mater? Will that pump affect the pressure and volume, or does it just circulate when needed.

    Like I said, My goal is to feed that new high flow shower with a dedicated 3/4" hot water line.
    The rest of the house I will be leaving on 1/2"
    Does this sound like it can be done?
    Can you offer me any advise or opinion on this?

    Attached Files:

    Last edited: Feb 13, 2010
  2. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    It won't help as you are feeding the hot water supply through the coil first. That's where your getting your flow restriction. You need to re pipe the setup so you are feeding the water tank and using the coil to circulate the water from the tank through the coil.

    John
  3. nhmaster

    nhmaster Master Plumber

    Messages:
    3,189
    Location:
    S. Maine
    John is correct. there's no point and no advantage to re-piping that. The best thing you could possibly do, would be to tear that old dinosaur out and replace it with something that gets better that 50% efficiency. A new boiler and indirect would pay for itself in about 5 years.
  4. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    Maybe this will help

    There is a coil in the old boiler. The water heater next to the boiler, I have been told, is an indirect (storage tank)
    I can feed the boiler with cold water on 3/4 copper
    I can feed the storage tank with hot water from the boiler on 3/4 copper
    the hot water output from the storage tank has already been changed to 3/4 copper
    The only place I cant seem to change is from the storage tank, thru the pump, and then back into to boiler.
    The nipple that comes out of the bottom of the storage tank is 1/2". It turns into the pump, with is also 1/2", and then goes through that flow check valve, and then tee`s into the proposed 3/4 cold water feed into the boiler.
    I hope I was able to explain that well. It seems to my amateur eyes, that the only thing that will be restricted is the return of water from the tank to the boiler. It seems it might somewhat restrict my recovery time. keep in mind that the return would be first teeing into a 3/4 copper pipe that actually enters the boiler as the cold feed.
    Everything has an available 3/4 tap. boiler, in and out. storage tank, in and out.
    The only place I see trouble is, bottom of tank return to boiler/thru pump. Is this what you mean John?
    Thank you both for the replies. Its a lot of work if I`m just wasting my time.
    Changing out the old girl is not an option at the present time.
    I will try to post a better picture.

    Attached Files:

    Last edited: Feb 13, 2010
  5. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    What you have is a old boiler with a coil that some one has tried to pipe through a water heater as a pre heater. They have also added a circulation loop from the coil to the heater. Your domestic hot water travels through the coil into the heater then out to the fixtures. It dose not go through the cir. loop that ties into the bottom of the water heater. If your looking for a quick fix, eliminate the coil altogether and just use the water heater. As I said before the coil is where the flow restriction is coming from. As Peter said give some series thought to replacing the boiler.

    John
  6. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    coil and flow restiction

    Good morning John, Thanks for taking a look at those pictures. I am not a plumber. I am just a homeowner who is trying to understand how the hot water gets to my shower. Please bear with me. Even If I cant increase the flow of hot water at least I would like to learn how it all works.
    In the photo that I have attached, I have indicated with arrows, the direction that the water flows. Can you tell me if this is correct?

    The hot water heater as far as I know is not powered up. It says 220 volts on it. That wire is only 110. I followed the wire through the hot water heater. It looks like it is attached to a thermostat and then exits the bottom to connect to the pump.

    When you say ; "The coil is where the flow restriction is coming from" Do you mean the coil in the boiler? That coil has a 3/4 tap in and a 3/4 tap out. Please explain how that is a flow restiction?

    When you say ; "It does not go through the cir. loop that ties into the bottom of the water heater" Can you explain that to me further? What goes through that pump and back into the boiler? Are my arrows in the picture all wrong?

    This is a boiler from 1945. 65 years young and still going strong. It produces steam for my heating system..

    Attached Files:

  7. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    The direction of flow is it enters the coil on the bottom exits the coil on the top to the water tank. From there it feeds the system. The circulation loop runs from the coil to the taping on the top of the tank that is marked cold, then out the bottom taping in the tank back to the coil. This is done just to heat the water in the tank. If you look you will see a check valve in that loop to prevent the cold water from entering the bottom of the tank. It sounds like they are using the thermostat in the heater to control the circulator. The problem is you have to maintain temperature in that old boiler weather it is calling for heat or not just to make hot water. As far as the coil being 3/4" the tapings may be 3/4" but the coil it self is more then likely so plugged the opening is smaller then a 1/2". There is another way to pipe it that would give you more volume of water but it's just not worth the time or effort.

    John
  8. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    Direction of water

    So it sounds like the arrows I made are correct. It also sounds like the hot water heater is in fact being used as a storage only tank. It is true that the steam boiler runs all summer long to make hot water. It is also true that the old coil in the boiler is most likely very plugged up. I plan to install a new coil into that old boiler if I can find one. Or take it out and get it cleaned?

    The fact that the coil in the boiler is all plugged up, is that what you meant by; "the coil is where the flow restriction is coming from" Or did you mean something else?

    One more thing, If I were to get a new boiler with an indirect tank, wouldn't the boiler still run all summer?

    I am also very curious about the other way to pipe it to increase flow that you mentioned. Could I ask you to elaborate on that?

    I need to drain the water in the boiler. It is very dirty. While I have all the water out of the system I thought it would be a good time to change out all of that 1/2" copper to 3/4". The fittings are cheap, I have the time, what could it hurt? The only thing I wont be able to change would be the return that goes through the pump at the bottom. I thought that would be the deal killer. From what you are saying its not. Do I have that correct?

    Attached Files:

  9. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    The re-pipe is not that much of a change. I'm just not sure of how the circulator is wired. For it to work it should be controlled by the lower thermostat on the heater. What needs to be done is to remove the cold water feed from the coil and feed the top right taping on the heater. This line should be 3/4". Put a 3/4" x 1/2" tee in that line and connect the existing 1/2' line that is coming from the top of the coil to it. Above that tee on the cold water feed you will need a check valve with the arrow on it pointing to the heater. Piping it this way eliminates the water going through the coil before going to the fixtures. The circulator will circulate the water between the coil and the tank to heat your water. The lower thermostat should control the circulator if that is how it's wired. I recommend that you get a professional to do this re-pipe.
    THIS IS NOT A DIY JOB.
    There also should be a thermal expansion tank installed on the heater. It also looks like the relief valve is piped with 1/2" and it must be 3/4".

    John
  10. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    pump orientation

    I have another question. Is that pump in the picture installed correctly. Someone mentioned to me that the pump should be orientated with the motor facing up, as opposed to the way it is now. Is that true?
  11. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    Yep, you were right

    I changed out most of the 1/2" copper to 3/4. During this process I took a peek into the 3/4 taps that go into that coil. You were right. the coil appears to be only 1/2" on the inside. I have to agree that having the cold water feed go in to that coil first is hampering the flow. Like I said, I have no immediate plans to change out this old boiler. I would like to work with what I have and make it as best as possible. I like the Idea you have about feeding the cold water supply into the tank. I can see how this might make a big difference in my hot water flow(volume). I have recently installed a high flow shower in the master bathroom.
    Everything in this new shower is piped in 3/4 copper. It is capable of using 10+ gals. per min. Currently, the cold water supply is all 3/4", from the basement to the mixing valve. The hot water however is hampered by that coil. I have a felling that if I do the re-pipe as you suggested, I will achieve the flow that I want. What I`m worried about is I will only get a 3 min. shower, because that tank is only 30 gals.
    What exactly is an indirect tank, and how is it different that the hot water heater that I have?
    Why would the plumber that did my house use a hot water heater?
    i have much to learn before I purchase an indirect tank for this system
    Given all the info that you have, What advise could you give me as far as supplying that new shower?
  12. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    You will get more then a 3min. shower as your not using just hot when taking a shower. But a 10 gal. per min. ( that's more like a car wash not a shower) you will need more storage capacity. At this point your have reached the maximum with the system you have. I see a new system in your future.

    John
  13. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,313
    Location:
    New England
    An indirect WH tank is basically just a big tank with either a coil or jacket that is heated by your boiler rather than having an internal burner or electric coil. You configure it as a separate zone for your boiler. Since a boiler typically has a larger burner than a stand-alone WH, you get faster recovery and a longer 'sustained' use. At 10gpm, you'd have to start with a substantial tank if you want to keep it at that level for long.
  14. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    It seems the Indirect would come with its own coil. I would no longer be dependent on the old coil in the old boiler. Can anyone tell from looking at my boiler pictures how an indirect would hook up to it. What about the old coil? How do I get the water to the new tank without going through that old coil? I dont see any other way in or out of that boiler other that the taps on the old coil.
  15. ballvalve

    ballvalve General Engineering Contractor

    Messages:
    3,261
    Location:
    northfork, california
    If you are going to use a 10 gpm shower, I suggest you pack the whole family in and some of the neighbors too. The money you save will pay for the new boiler...
  16. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    Last comment

    That last comment is not helping me understand my hot water system. The re-pipe that was suggested by 02-14-2010 12:19 PMjohnjh2o1 is very interesting to me. I am considering making the change that john suggested. Opinions on this re-pipe are welcome. I would love to know how the rest of you feel about the re-pipe idea.
  17. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    New plan

    Is this going to work? I would end up with 3/4 cold water feed, and 3/4 supply out to shower. 1/2 feed from coil, and 1/2 thru pump back into coil.

    Attached Files:

    Last edited: Mar 5, 2010
  18. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    That's the way I would pipe it. But you MUST install a thermal expansion tank. Also the line coming of the relief valve MUST be 3/4" it looks to be 1/2".

    John
  19. wallygater

    wallygater New Member

    Messages:
    133
    Location:
    long island
    Ok. sounds good. I wonder why it was piped the way it is now?

    The new configuration will have the cold water feed going into the top tap of the coil. Does that matter?
    Can I eliminate the 3/4-1/2-3/4 tee and have it go all 3/4 into the top tap on that coil? Does that matter?
    Do I have the new location for the back-flow preventer in the right place?
    I have noticed that the pipes that run from the bottom of the tank, through the pump, and the into the coil, are ice cold. Only when the pump turns on do they heat up. Is that normal?
    Why would the water coming out of that tank be ice cold?
    When I do this new re-pipe I suspect that the water going into the tank will now be ice cold. As opposed to hot the way it is now. What effect will that have on my system overall? Will the pump run more often? Will It be less efficient that it is now? Will the boiler have to run more often than it does now to keep the water hot?
    This system has never had an expantion tank on it. I have never had a pressure problem, and that relief valve has never seen a drop of water. Will the new configuration effect that?
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