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Liner leaking?

Hello all,

I had a new heat pump with a back-up 80% furnace installed a 18 mo ago.

The only issue I have is condensation/slush build up. The condensation pools at the bottom of the liner where its flexed 90* to exit the chimney in the basement. On the coldest days its slushy and melts, draining back towards the furnace. Where is seeps out the collar, across the floor and into the drain.

I never had this issue with my old furnace which was almost twice the capacity though.

I had the company that rebuilt the chimney from the roof up come take a look and he didnt have a solution. He checked the draft and did a visual inspection with a camera and noted no issues. Still looked almost new.

Is the liner over sized? should it be replaced with an insulated liner?


Comments

  • random12345
    random12345 Member Posts: 299
    I'm not a pro. What is the btu input rating of the furnace? gas, oil, propane? Looks like you have a water heater there as well...what is its btu rating? What is the diameter of the liner, height of the chimney, length of the vent connectors from the water heater and furnace to chimney? They look to be single walled...are they? Is the vent connector pitched up at least 1/4" rise per foot? Is it an external chimney (3 sides exposed to the outside)?
    Bob HarperEdTheHeaterMan
  • Jamie Hall
    Jamie Hall Member Posts: 20,417
    Flexed 90 degrees to sit the chimney? I don't like. My guess is that it is flexed in such a way as to create a pocket which can trap condensate. That won't last long...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Bob HarperEdTheHeaterMan
  • Bob Harper
    Bob Harper Member Posts: 955
    You need to run combustion analysis to see if the unit is underfired and if the draft pressure is too weak. The code and most listings do allow for the base of the liner to sweep into the Combustion Appliance Zone (CAZ) but it must slope downwards 1/4" per LF as noted. If it traps condensate, as Jaime said, it will eat up that liner in short order. BTW, no foil tape on the connector joints. You can have the chimney contractor install a stainless-steel tee at the base of the vertical liner as a condensate trap, but it will act as a bucket and fill up. You could have them fabricate and install a ss wye where it exists the wall with the upper branch to the vent connector and the lower leg into a removable stainless-steel cap. Here, you can install a condensate drain to silicone tubing looped into a trap and channel that off for proper disposal. You can install a tee with a double acting barometric damper on the furnace and a bullhead tee with double baro. on the WH and protect them with spill switches.
    Does your unit sit for prolonged standby times? Set back t'stat?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,913
    edited October 2022
    Any venting system that is connected to a Category III (3) appliance should not develop so much condensation that it will leak liquid regularly. There is an incorrect appliance BTUh to vent size ratio. You need to correct the appliance size or the vent size so they match. @random12345 is asking all the right questions. The charts are in the NFPA 54 book for a reason. This is one of them.

    Who is responsible for this?... depends on what was there first. If the Liner was there first, then the furnace installer needed to do their homework. If they did not do their homework, then they are responsible for this problem and the resolution of it. Did you pay in full yet?

    If the liner was installed to match the new furnace, then the liner installer is responsible to make the proper size selection. Is that paid in full?

    Were permits pulled for this work? Did the work pass inspection? If so, there is another party to get involved in the dispute, and ultimate resolution.

    If no permits were secured, then you might ask the installer(s) what might happen to their license if you asked the inspectors to get involved? But careful, this could backfire if you do get the inspectors involved. You may need to pay the permit fee and fines involved. Then Lawyers get to take more money, and you still have the problem while this all gets settled.
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • rconkling
    rconkling Member Posts: 49
    Its a z-flex aluminum liner I installed 10ish years ago. I dont remember the size, i sized it to meet the demand of the old furnace and water heater. I was unemployed and did it as cheaply as I could, with minimal knowledge and skill. Im impressed it was in tip top shape, per the camera scope, at its age. Since the reading I did back then was that it would only last 5ish years.

    I replaced the 28yr old water heater with a new hybrid heat pump. Then I had the HVAC replaced with a heat pump and 48k btu output back-up furnace. If I were to do it all over, i dould sized the HP to not require backup heat.

    Maybe the HVAC was replaced before the water heater. I dont remember. Though that might explain why the HVAC installer didnt think it needed to be replaced.

    The liner drafts fine, tested by the chimney guy. Slope is also fine, verified by the chimney guy.

    The chimney is a dual flue, one for the fireplace, the other for HVAC. Slightly over 1/4 of the surface area is exposed.

    Appreciate the help. It appears I need a smaller liner.

    Cheers

  • random12345
    random12345 Member Posts: 299
    edited October 2022
    rconkling said:

    Its a z-flex aluminum liner I installed 10ish years ago. I dont remember the size, i sized it to meet the demand of the old furnace and water heater. I was unemployed and did it as cheaply as I could, with minimal knowledge and skill. Im impressed it was in tip top shape, per the camera scope, at its age. Since the reading I did back then was that it would only last 5ish years.

    Good for you. Not sure how tall your chimney is. I would not have dared to attempt this on our house. I thought about it, but we're on a hill and 40-60 ft drop onto pavement was not a risk I was willing to take. I too have heard aluminum liners are best avoided.
    I replaced the 28yr old water heater with a new hybrid heat pump. Then I had the HVAC replaced with a heat pump and 48k btu output back-up furnace. If I were to do it all over, i dould sized the HP to not require backup heat.
    If you live in my town with $0.3219/kwh rate, you would have gotten killed on your electric bill though. How is the heat pump water heater working out for you? Noisy? I'm thinking about getting one.
    Maybe the HVAC was replaced before the water heater. I dont remember. Though that might explain why the HVAC installer didnt think it needed to be replaced.

    The liner drafts fine, tested by the chimney guy. Slope is also fine, verified by the chimney guy.

    The chimney is a dual flue, one for the fireplace, the other for HVAC. Slightly over 1/4 of the surface area is exposed.

    Appreciate the help. It appears I need a smaller liner.

    Cheers
    48k btu is not a lot. The NFPA 54 tables will tell you.



    rconkling
  • rconkling
    rconkling Member Posts: 49



    Good for you. Not sure how tall your chimney is. I would not have dared to attempt this on our house. I thought about it, but we're on a hill and 40-60 ft drop onto pavement was not a risk I was willing to take.

    Im tempted to do it again with the same unit, smaller diameter. Since they are so cheap and lasted so well. Ill have to see what they quote me.

    I wont be doing it on the new house, 2+ stories, much steeper pitch.

  • pedmec
    pedmec Member Posts: 712
    can you take better pics? almost feel your trying to hide something. please move back and take full view. need good pics to give you good feed back.
  • rconkling
    rconkling Member Posts: 49
    Its a z-flex aluminum liner I installed 10ish years ago. I dont remember the size, i sized it to meet the demand of the old furnace and water heater. I was unemployed and did it as cheaply as I could, with minimal knowledge and skill. Im impressed it was in tip top shape, per the camera scope, at its age. Since the reading I did back then was that it would only last 5ish years.
    Good for you. Not sure how tall your chimney is. I would not have dared to attempt this on our house. I thought about it, but we're on a hill and 40-60 ft drop onto pavement was not a risk I was willing to take. I too have heard aluminum liners are best avoided.
    I replaced the 28yr old water heater with a new hybrid heat pump. Then I had the HVAC replaced with a heat pump and 48k btu output back-up furnace. If I were to do it all over, i dould sized the HP to not require backup heat.
    If you live in my town with $0.3219/kwh rate, you would have gotten killed on your electric bill though. How is the heat pump water heater working out for you? Noisy? I'm thinking about getting one.
    Maybe the HVAC was replaced before the water heater. I dont remember. Though that might explain why the HVAC installer didnt think it needed to be replaced. The liner drafts fine, tested by the chimney guy. Slope is also fine, verified by the chimney guy. The chimney is a dual flue, one for the fireplace, the other for HVAC. Slightly over 1/4 of the surface area is exposed. Appreciate the help. It appears I need a smaller liner. Cheers
    48k btu is not a lot. The NFPA 54 tables will tell you.
    48k is the max. It’s a 2 stage furnace. Running on low most of the time. 
  • rconkling
    rconkling Member Posts: 49
    You need to run combustion analysis to see if the unit is underfired and if the draft pressure is too weak. The code and most listings do allow for the base of the liner to sweep into the Combustion Appliance Zone (CAZ) but it must slope downwards 1/4" per LF as noted. If it traps condensate, as Jaime said, it will eat up that liner in short order. BTW, no foil tape on the connector joints. You can have the chimney contractor install a stainless-steel tee at the base of the vertical liner as a condensate trap, but it will act as a bucket and fill up. You could have them fabricate and install a ss wye where it exists the wall with the upper branch to the vent connector and the lower leg into a removable stainless-steel cap. Here, you can install a condensate drain to silicone tubing looped into a trap and channel that off for proper disposal. You can install a tee with a double acting barometric damper on the furnace and a bullhead tee with double baro. on the WH and protect them with spill switches. Does your unit sit for prolonged standby times? Set back t'stat?
    It’s idle 75% of the winter, it’s the back-up for a heat pump. And firing at 60% power most of the time.