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Boiler not making temp.

MTR Member Posts: 8
We just completed a new installation at a commercial facility.  2 zones of radiant and 4 hydro air units.  As the outdoor temps have been dropping, the space hasn't been keeping temp.  The 2 areas with radiant also have 2 hydro air units w/erv's to temper the incoming fresh air.  Other 2 hydro air units serve office areas.  Radiant areas haven't been too much of a problem but the office areas are.

Was onsite last Friday.  Outdoor temp was 37*.  Indoors couldn't get the office above 64*.  Secondary loop 130*.

We have a WM Ultra 230 boiler.  First thought was boiler too small or piping messed up somehow.  The secondary loop temp wouldn't go above 130* with all zones calling.  Turned off all zones except one hydro air unit.  Secondary loop increased to 135* over the course of 10 minutes.  Delta T is 20*.  Boiler is calling for 160* water but only supplying 130*

Had the rep down today.  He thinks the boiler is undersized.  Not sure yet if that is the case but if it was, why would the boiler not be making temp. with only one air handler calling. 

Then said the pumps may be too small.  With the delta t 20* when all zones are calling or 1 zone calling, i don't think it's the problem.

Been scratching my head.  Only thing I can think of is something wrong with the boiler.


  • Eric L._2
    Eric L._2 Member Posts: 94
    That is exactly what is happening with the Solia in my post.

    Any ideas?
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    Fuel supply issue?

    Has anyone checked the fuel input to the boiler to make certain it is where its supposed to be? Has anyone done a combustion analysis?

    Was the fan running full speed?

    The other thing I have seen kill a heat load is infiltration. In your case, you have a mechanically induced infiltration factor, but with that off, the boiler should be able to achieve higher temperatures.

    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • MTR
    MTR Member Posts: 8
    The rep.

    called an engineer from WM with all the temps, delta t, gas pressures etc.  They said it's running at 100% and it's something wrong with the system.

    Didn't do a combustion analysis yet.

    I may have to swap out the boiler with another but wanted to see if I was missing anything before I spent the time & money.
  • R Mannino
    R Mannino Member Posts: 440

    Make sure the venting is clear, partial blockage with condensate or anything else will cause what's happening. Please don't ask how I know. :-)
  • CMadatMe
    CMadatMe Member Posts: 3,086

    Need more information. What size is both your primary and secondary loop piping? What is the tonage of the a/h's? Are they zoned with individual circs? What size piping to the a/h's? Is there a differential by-pass in the system piping? Could you provide a schematic of how the boiler is piped or better pictures?

    The last question I have it WHAT IS THE HEATLOSS of the building and each zone?
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • MTR
    MTR Member Posts: 8
    Flue is

    clear.  When we took the cover off there was a lot of dust/particles in the bottom of the boiler.  Also, the cond. drain was almost plugged with junk.  Cleaned it out and pulled the cover off the heat x.  The bottom 2/3 of the heat x looked dirty and had little particles stuck on the fins.  You need a 3/4" x 18" piece of sheemetal to clean in between the heat x fins.  Sticking the metal in straight from front to back was okay to clean.  Trying to get it on an angle to clean,  in some spots it wouldn't go all the way in.  I think about 1/3 of it is blocked.

    The rep. didn't think this was a problem but I would think it would affect heat transfer.
  • MTR
    MTR Member Posts: 8
    Primary loop

    is 1.5".  Secondary starts out 2", reduces to 1.5" after 1st fan coil.  Next feeds 2nd fan coil & 1 zone of radiant.  Main stays 1.5" then feeds 2nd radiant zone, and last 2 fan coils.  The branch lines for these are all within 6'.  Piping to each fan coil and radiant zones is 1".  There is a Taco 0011 on the mains serving the fan coils.  At each radiant manifold, there is a Viega mixing station w/diverting valve and circulator.

    Each fan coil has a 2 way control valve.  Upon a call from any fan coil or radiant, the main circulator is enabled.

    We found the radiant circulators didn't have enough head to pull from the mech room, through the mains, back to the radiant.   By enabling the main circulator, it solved the problem.

    I'll get the loads and a sketch when i get to work in the am.
  • icesailor
    icesailor Member Posts: 7,265

    How did you determine how many BTU's to add to the mix for this? I have found that something like this is very hard to engineer.

    Shut that thing off and see if the temps go up.

    That boiler is only good for 183,000 BTU net. What's your computed load?

    Are you sure that all the pumps on the boiler are working? I heard about one this weekend that a system pump wasn't working but it was blowing the fuse on the brain board.
  • World Plumber
    World Plumber Member Posts: 389

    The heatexchanger is partially blocked and the rep doesn't think that has any bearing. Scratching my head. 
This discussion has been closed.