Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Weil Mclain Hot Water Boiler Issue with Heat Not Reaching 2nd Floor

ashishm02
ashishm02 Member Posts: 6
in Gas Heating

Hi guys,

Long time watcher, 1st time poster here. Hoping you guys can help, like you have countless others…

I have a Weil-Mclain boiler (CGa-5, Series 1). It was working completely fine for many years, but this year, heat is not reaching 2nd floor baseboards at all. It perfectly heats up my basement and 1st floor. Below is what has been done so far in my investigation:

  • There are no error codes on the control board
  • Honeywell zone valves have been replaced on all 3 zones.
  • Backflow preventer, Pressure Reducing Valve, Circulator pump have been replaced.
  • The psi gauge on top of the boiler is accurate, because tested by buying another gauge and hooking up to the spigot on the return line.
  • I don't have any bleeder valves, but did push water thru the 2nd floor piping and drained it using spigot on the return line.
  • Verified that the damper is working as expected.

I had a hvac guy come out and he said that the heat exchanger is bad, so it is causing the flow rate to be reduced, hence water is not reaching 2nd floor. He increased the pressure on the boiler by closing the shut off valves on both the supply and return line on top of the boiler, so the relief valve would blow and push all the gunk out. When he did that, the heat did reach the 2nd floor for a few minutes. So he is saying that the entire boiler needs to be replaced.

Before I go that route, I wanted to ask here if you guys feel the same? Can it be anything else? I have no other issues with this boiler, so don't want to replace the whole thing, if not absolutely necessary. I am handy, so am willing to try anything else that you guys can think of. Also, is the heat exchanger something that can be replaced?

Thanks,

John M.

Comments

  • neilc
    neilc Member Posts: 2,841

    if it were the boiler, you would have no heat,

    post a picture or 2, general view of boiler, circ(s), valve(s), and where you drained from, general wide angle view,

    seems like 2nd floor is still air bound, and need a purge,

    let's see what you got

    known to beat dead horses
    IronmanHomerJSmith
  • neilc
    neilc Member Posts: 2,841

    and what pressure are you reading on the gages?

    known to beat dead horses
  • HVACNUT
    HVACNUT Member Posts: 6,298

    Maybe the boiler is a mess. We don't know. But if you have heat on the first floor and basement, then it's likely zone related, not boiler related. Has anyone removed the second floor thermostat and jumped the wires going to R and W? Is there also air conditioning on that thermostat? When the zone valves were replaced, was 24 volts to the motors verified when the thermostats were raised above room temperature? Could be air locked, but even thats an easy fix if it's a simple loop. Is it? This is basic stuff. Find a new tech.

  • ashishm02
    ashishm02 Member Posts: 6
    edited November 30

    The pressure gauge is reading about 18 PSI (I put it a little higher then the 15 PSI, since my circ pump is mounted vertically). Also, I have put the high limit to 200F.

    Attached are the pics.

    When you say, "if it were the boiler, you would have no heat," - Are you saying if the heat exchanger piping had reduced flow due to gunk I wouldn't get any heat at all?

    Thanks,

    John M.

    IMG-20241130-WA0004.jpg
    IMG-20241130-WA0005.jpg
    IMG-20241130-WA0006.jpg
    IMG-20241130-WA0003.jpg
    IMG-20241130-WA0002.jpg

  • ashishm02
    ashishm02 Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1823403#Comment_1823403

    Has anyone removed the second floor thermostat and jumped the wires going to R and W? —> Yes, I jumped the wires on the 2nd floor thermostat and confirmed that the zone valve opened. Also, the zone valve is brand new (replaced 2 weeks ago), however this issue started 3 weeks ago.

    Is there also air conditioning on that thermostat? —> Yes, there is air conditioning on the thermostat also.

    When the zone valves were replaced, was 24 volts to the motors verified when the thermostats were raised above room temperature? —> Yes I did that and 24 volts to motors was there, when the thermostat called for heat.

    Could be air locked, but even thats an easy fix if it's a simple loop. Is it? —> It still could be air locked, but how do I fix that?

    Thanks,

    John M.

  • Ironman
    Ironman Member Posts: 7,539

    Most likely an air binding issue if the zone valve is opening and the circulator is working.

    I’ve never seen a heat exchanger plugged where water wouldn’t circulate on a cast iron boiler.

    The mounting position of the circulator has nothing to do with the required pressure; its location in regards to the Point Of No Pressure Change does.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • HomerJSmith
    HomerJSmith Member Posts: 2,635

    I'm reminded about a feller that went to a Doctor about a pain and the Doctor told him he had cancer and the feller said that he wanted a second opinion, so, the Doctor said, "Your ugly, too."

    You need a second opinion. Don't just believe what you're told.

    Ironman
  • neilc
    neilc Member Posts: 2,841

    try purging the 2nd floor again,

    turn the boiler off at the service switch,

    shut the ball valve under the hose drain.

    shut the 2 working zones, thermostats all the way down, resistance on the manual levers, (these should be closed when you power down the boiler)

    manually open the 2nd floor valve, lock it in the manual notch,

    open the hose drain, using the fast fill, get and maintain system pressure up around 20-25, (don't get closer to 30 or you may test your safety valve),

    let it run a few minutes and make sure no air bubbles, or run it till bubbling stops and you have steady water only,

    close down hose drain, and release fast fill, set pressure back down to 12ish,

    reopen the ball valve below hose drain,

    release manual position on second floor zone valve,

    restart boiler,

    success(?)

    known to beat dead horses
    HVACNUT
  • neilc
    neilc Member Posts: 2,841

    what I said about "not the boiler",

    if you have heat circulating to the 2 bottom zones then you have circulation thru the boiler also, it's making that heat, just need to get circulation to the second floor,

    known to beat dead horses
    HVACNUT
  • neilc
    neilc Member Posts: 2,841

    don't forget to set that boiler temp back down to 180, 170, ish,

    where are you located?

    known to beat dead horses
  • ashishm02
    ashishm02 Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1823429#Comment_1823429

    Will try those steps tonight. Also, I am located in Central NJ. I just set it to 200F for testing and will set it back to 180 after finish testing. Thank you so much for your help.

  • ashishm02
    ashishm02 Member Posts: 6

    NeilC - Thank you, Thank you, Thank you, Thank you, Thank you, Thank you!!!

    Your steps solved the issue that I had been struggling for the past month. I can't believe it. I am finally getting heat upstairs! You guys rock!!!

    HVACNUT
  • pedmec
    pedmec Member Posts: 1,060

    You might need to check after 30 minutes. When you purge you manually putting hot water thru the loop. fools people into thinking they have heat when they really don't.

    I'm assuming you have baseboard heat?

  • ashishm02
    ashishm02 Member Posts: 6
    https://forum.heatinghelp.com/discussion/comment/1823555#Comment_1823555

    Hi - Yes, it's been working for a few days now. It is baseboard heat and I am so glad it's fully working again :).

    You guys rock!!!

Categories