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Pitching exhaust towards termination.

tibDeltT
tibDeltT Member Posts: 1
in Chimneys & Flues

I recently installed a new IBC boiler. I failed inspection on the venting. Because of the location of the unit and the house being finished I had to run the venting up and then down to its final termination. I left no bellies in the pipe for condensate to accumulate but it's not exactly to the manufacturers recommendation. I don't understand what could possibly happen. Sure you will have water dripping out of the exhaust pipe. But other than that what's the problem. I've had the unit installed for a month now and no error codes. I've done this before no call back. I'm in San Francisco California and no chance of freezing weather. Please some show me the light or tell me I've broken the matrix.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 25,190

    Bottom line, if it failed inspection and your installation is not in accordance with the manufacturer's requirements… you're stuck.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,765

    All boilers are supposed to be installed to the vent slopes up from the boiler. They want the condensate to run back to the boiler to drain.

    They are not going to re right the boiler manuals or codes just because you live in an area not subject to freezing.

    The MFG install instructions take precedence over any local codes

  • JMWHVAC
    JMWHVAC Member Posts: 57

    You are correct, mechanically it will work fine sloping out. I have done it and we have freezing temperatures. (As long as the location of the block of ice below the exhaust doesn't bother anybody!) But yes, inspection is inspection. In my area, inspectors seem to spend very little time on boilers unless it is a commercial application.

  • Kickstand55
    Kickstand55 Member Posts: 112

    Always best to check all pertinent information before installing. That way, you get paid. If the equipment doesn't

    fit the application, modifications may be needed to the structure or system relocated to another area.

    Sometimes it can't be done.

  • Long Beach Ed
    Long Beach Ed Member Posts: 1,411

    Depending on your state, you may be able to have a professional engineer write a statement that the installation is sufficient, safe and correct. In many,if not most areas, that would suffice.

    PC7060
  • hot_rod
    hot_rod Member Posts: 23,736

    that condensate running back to the boiler helps keep the HX surfaces clean. It runs across the surfaces to get down to the condensate drain.

    Depending on operating temperature and hours if run time, you could have a bit of water to deal with outside

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Boring
    Boring Member Posts: 48

    I was just looking through my Knight boiler installation manual to see if there were any slope specs for intake and exhaust….I didn't see anything…however, if vents/intakes are vertical it's a no brainer where condensate will go….but in my case. I have a PVC Concentric vent going through a wall…it started howling a few years ago…and someone suggested that condensate may be collecting in the vent pipe causing a resonate when combustion gases go past the condensate….I placed a level on the hot gas exhaust and its pretty much level….should it be sloped towards the boiler? I don't believe the intake should matter or does it?

    Boring

  • Bob Harper
    Bob Harper Member Posts: 1,095

    The hump creates a flow restriction- period. The unit is designed for a certain static pressure in the venting. This is clearly illustrated by the manual offering approved configurations of venting depending upon lengths, elbows, etc. They run a few minimum and maximum iterations then calculate in between.
    Aside from the legal obligation to install per the manual, which becomes the DeFacto code, running combustion analysis is the only way to know if there is adverse effect or not.

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