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Hot water heating system problem

Jack_2Jack_2 Posts: 21Member
I recently replaced finned aluminum to cast iron but when I turned on the heat to test, it was not getting hot. I have a mixed finned and cast iron hot water system where the other units were getting hot but not the ones I replaced. I have one supply and one return system on boiler but don't know rest of piping as it's in the walls. House was built appx. 1950. Any ideas? Thanks.

Comments

  • ZmanZman Posts: 4,969Member
    We are going to need a lot more info. It sounds like you may have modified an old monoflow system.
    Do you have pictures or a drawing?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,577Member
    I bet it's a monoflo and you will need to bleed bleed bleed!
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
  • Jack_2Jack_2 Posts: 21Member




    The first pic is the piping in the boiler. The second and third is the original aluminum fins and the last is the cast iron convectors I had installed as a replacement. Thanks
  • Intplm.Intplm. Posts: 760Member
    You most likely have air in your system. You will need to replace that air with water.
    Purge the system and bleed the air out of the radiators. You should get heat when you do that.
  • Jack_2Jack_2 Posts: 21Member
    It was already bled. Is it possible that the guys who did this missed turning a valve back on that supplies those radiators??
  • Intplm.Intplm. Posts: 760Member
    Its possible. You have two circulators. That should mean you have two zones. Do you actually have two heating zones or is one circ. used for a indirect water heater?
  • Intplm.Intplm. Posts: 760Member
    Also. Those types of rads can be a bear to purge. Patients and determination is key to getting all of the air out.
  • ZmanZman Posts: 4,969Member
    Do you have pictures of the tees underneath? A picture of the boiler from farther back?
    I am thinking you have a monoflow and you are pumping into the expansion tank. Kind of a frustration setup to get purged.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • HVACNUTHVACNUT Posts: 2,254Member
    The pic of the CI rads is not wide enough. Do the rads themselves have air vents?
    If it is a monoflo system, they need them, just like the old ones had.
    And if it is a monoflo system, was any piping changed at the branch Tee's?
  • Jack_2Jack_2 Posts: 21Member
    It was a 2 zone at one time but I made it into one zone with both pumps controlled by one thermostat. I will post a wider pic of boiler but clearance in very limited in very small boiler room. I'm not familiar with tees and branching since all that stuff is the walls and between floors. The CI has air vents on supply and return sides. Will post pis of that as well. Thanks.
  • Alan WelchAlan Welch Posts: 148Member
    Make sure both blue handles in the first picture are open.
  • STEVEusaPASTEVEusaPA Posts: 2,979Member
    edited August 5
    Did it get warm as you were bleeding it?
    steve
  • Jack_2Jack_2 Posts: 21Member



    The first pic probably is not so clear as to which pipe goes where but you can see the purge tank on top left. The second pic is the air valves on both sides of the new CI rads. I was wondering since the piping on the new rads is not exactly straight like the previous aluminum slants, could this cause weak flow and necessitate a more powerful pump?
  • Jack_2Jack_2 Posts: 21Member
    So anything with a blue valve should be open, correct?
  • Jack_2Jack_2 Posts: 21Member
    Should the purge tank valve be open as well?
  • Jack_2Jack_2 Posts: 21Member
    I'm assuming blue means cold water and red is hot water?
  • Alan WelchAlan Welch Posts: 148Member
    I mean the two blue handles (round wheels) above the black circulator on the horizontal pipe, and above the red circulator on the vertical pipe. the expansion tank appears to be in the upper RIGHT , and the silver handle to the left of the union should be open as well. ( or just call the installer and have them take care of it because you aren't heating)
  • Jack_2Jack_2 Posts: 21Member
    Alan, I moved into this house about 4 years ago and this boiler with its piping is the way I got it. I know I'm going out on a limb here, but do you see anything that is strange or could be improved? Thanks.
  • Alan WelchAlan Welch Posts: 148Member
    My point is that if someone else did the job it should be there responsibility to make sure it heats. Did you tell them how to do it? They may have left a valve shut , they may have piped it wrong. I can't tell how they looped the 2 units together, maybe they kinked a pipe, maybe you didn't give it enough time to heat. Cast iron and baseboard don't work well together on the same zone.
  • Jack_2Jack_2 Posts: 21Member
    They didn't test it after they finished the job. I think because of the issues I'm having now. One large CI rad they replaced is working perfectly since a smaller CI rad was there already. I'm assuming the piping for that one was done correctly before I moved in 4 years ago. So, I already had mixed CI with aluminum slants BB and they worked well with a stronger pump I installed about 3 years ago. Th reason I replaced some BBs is because they tended to cool down much faster than the CIs I already had when the boiler cycled off. But I will test this weekend by air purging all the units i have (about 25) and will let you know how it goes. The installers suggested I should also consider a stronger pump because the piping for the new rads are not as straight as the old BBs they replaced.
  • Alan WelchAlan Welch Posts: 148Member
    Can you remove the lower panels on the 2 radiators and post a picture of the piping?
  • Jack_2Jack_2 Posts: 21Member
    Yeah. I figured you might want that. Will post tonight when I get home. Thanks.
  • Jamie HallJamie Hall Posts: 10,548Member
    "Th reason I replaced some BBs is because they tended to cool down much faster than the CIs I already had when the boiler cycled off."

    Ooops. That's the nature of finned baseboards. Can't fixt that.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Jack_2Jack_2 Posts: 21Member



    Alan, sorry I didn't get back to you earlier. Here are the pics you requested but don't know if you can make anything out of it. I'm assuming the supply is on the right while the return is on left of the second smaller CI. The piping in the middle is to attach the larger CI on right to the smaller one on the left. When I open the purge valve on either side, only water comes out. Thanks.
  • pecmsgpecmsg Posts: 797Member
    Assuming the supply is on the right you could have AIR trapped in the high point!
  • pecmsgpecmsg Posts: 797Member
    Even if its the return it could still be air bound
  • Jack_2Jack_2 Posts: 21Member
    pecmsg, "high point" meaning what, exactly? I have purge valves on both rads and only water comes out so don't know where the air might be trapped. From what you see, is the piping correct? Thanks.
  • Alan WelchAlan Welch Posts: 148Member
    I think what you are calling a purge valve is a bleeder, meant to get air out of the top of the radiator. what pecmsg is referring to is the piping on the lower right hand radiator. the piping coming out of the floor pitches down to the left, and air can get trapped there and stop the water from circulating.
    even if you get the air out i'm not sure it would heat well, a lot of restriction in the piping. it would have been better to make each radiator its own loop off the main.
  • ZmanZman Posts: 4,969Member
    If it is is a typical monoflow with just 1 venturi, there may be too much resistance in all that piping to allow flow to radiators.

    Do you have pictures of the tees under the floor? What size circulator and piping?
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Jack_2Jack_2 Posts: 21Member
    Zman, all the connections and tees to the mains are inside walls and floors and I would have to break into them to see what's going on. But the guys who did the above also changed another CI rad into a larger size with the same connections but no pipe pitching like above and that works great. I will post pics of that rad maybe tonight and you'll see it's more or less the same. The original piping going into the aluminum slants looks to be 1/4" although not certain. About 3 years ago, I changed the circulator pump into a much more powerful one and that solved my heating problems then because some of the aluminum slants weren't getting hot. I don't why the installers slanted that pipe when they should've raised the rad accordingly.
  • Jack_2Jack_2 Posts: 21Member
    Does anyone here know if the Walabot can see thru pipes and detect air pockets? Or some similar device that can do this? Thanks.
  • CanuckerCanucker Posts: 534Member
    Infrared camera might show you where the heat is stopping. Never used walabot
    You can have it good, fast or cheap. Pick two
  • ratioratio Posts: 2,033Member
    I don't think a Walabot will see through a metal pipe. Perhaps plastic, IDK. Mine hasn't performed as well as I had hoped, but I've only played with it so far.

    I second the IR camera, though. I've got a Fluke VT-04 that has preformed admirably in chasing a leak in a radiant floor; & I recently purchased a FLIR One after seeing video made with one here. (I'm on a phone, else I'd add links & @mentions, sorry.)

  • ratioratio Posts: 2,033Member
    Come to think of it, @Canucker might want to tell us about his phone, maybe? :sunglasses: :sunglasses: :sunglasses:
  • CanuckerCanucker Posts: 534Member
    > @ratio said:
    > Come to think of it, @Canucker might want to tell us about his phone, maybe? :sunglasses: :sunglasses: :sunglasses:

    You know you want one. Write it off as a business expense? :p
    You can have it good, fast or cheap. Pick two
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