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boiler output

John_224 Member Posts: 4
nothing has changed that I know of it just doesn't seem to be able to keep up, do I need a new boiler


  • John_224
    John_224 Member Posts: 4
    boiler output

    I have a weil-mclain cast iron boiler serving one zone of radiant heat. The boiler is piped in primary secondary. On a call for heat the primary circuit runs and when it reaches 140 a strap on aquastat turns on the secondary loop circulator serving the radiant, which in under a minute drops the temperature of the boiler loop to around 100 degrees, and it takes at least five minutes for it to get back to temp., which starts the process all over. It will run like this forever and never get heat to floor. It seems as if the boiler is undersized but it has worked in years past. Is there something that would lower boiler output? I placed my hand on the flue pipe six inches above boiler it gets fairly hot, but above it the smoke pipe only gets lukewarm. The vent damper seems to open and close fine. It seems that the flue pipes should get hot but they don't I'm not sure. When I Looked in the boiler there was a pile of what looks like chunks of rust in the burner tray, and the flame seems to roll out through a gap between the boiler block and the top of a piece of metal with a hole to view the pilot through. I shut the boiler off since I have forced hot air as a backup, I'm just wasting gas. Is there something wrong with my boiler that would cause it not to create enough heat to keep up, It is only six years old.
  • Mark Custis
    Mark Custis Member Posts: 539
    In floor radiant

    is the way to go.

    The back up is just that, back up.

    What has changed?
  • Brad White_191
    Brad White_191 Member Posts: 252
    John, get a pro in there NOW

    If you have flame roll-out, forget heating your house. You have a dangerous condition, possibly a collapsed chimney liner (from years of below-dewpoint operation). Just a guess but I would rather be safe than sorry.

    I want you to see 2009, all of it and more.

    Please let us know what you are doing about this.

    At least you have another source of heat...but is it into the same chimney?

    To that boiler, what is the heating load and boiler capacity relative to that? If the boiler can handle the load, the temperatures need better management- a return water protection setup for example. We should also look at your flow rates in each loop. But check the combustion aspects and chimney with a pro first.
  • Mark Custis
    Mark Custis Member Posts: 539
    New Boiler?

    Maybe, but I guess not. You need someone that is qualified to examine the system and stop the flame roll out. My guess is the chunks of stuff is soot.

    Get the machine serviced and cleaned asap. Then you can get someone to rework the piping and install proper control system for the floor.
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