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monoflo convection rads house 65 Degrees

kirk42
kirk42 Member Posts: 9
in THE MAIN WALL
Hi Guys  Changed out an old National hot water boiler mono flo system w/ recessed convection rads with a Weil Mclain CGA-4 with a Taco 007 on supply.Cannot get temp in house over 65 degrees on a cold day(below 35F) Bled rads multi times,vacuumed fins,bled again and again.Boiler reaching temp no problem,135 degrees coming out of top of rad.cover.Changed thermostat three times. Circulator facing correct direction. Any Ideas would be great!  Thanks

Comments

  • Paul48
    Paul48 Member Posts: 4,469
    Hi-Limit

    What is the hi-limit set to on the boiler?
  • kirk42
    kirk42 Member Posts: 9
    limit temp

    Limit is set for 180 degrees and unit is running at 190 per the temp.gauge.
  • icesailor
    icesailor Member Posts: 7,265
    Water flow:

    Is the water flowing in the correct direction after you changed the boiler and re-connected the system?

    If it worked before you shut it off and changed it, and it doesn't work now, what changed?
  • kirk42
    kirk42 Member Posts: 9
    Circulator direction

    Yes the circ.is going the proper direction off the supply,old unit was a B & G 100 off the return.Old steel expansion tank in ceiling is now a #30.
  • kirk42
    kirk42 Member Posts: 9
    #30 expansion tank

    And the #30 expansion tank is off a tee on the return.
  • Paul48
    Paul48 Member Posts: 4,469
    Different

    The 100 series at 6 ft/hd is pumping 20 gpm. The 007 at 6 ft/hd is pumping 13 gpm. I don't know how to calculate which circ would be best for your application. I'm sure there are some people here that would be capable, but the calculations are like a different language for me.The calculations change depending on the position and quantity of tees.
  • kirk42
    kirk42 Member Posts: 9
    B&G 100

    I was considering moving the circ.back to the return thinking it was some kind of pressure loss situation.Think you may be onto something with the 100 series,maybe this monoflo needs the velocity.
  • Paul48
    Paul48 Member Posts: 4,469
    If

    it worked before. The Taco 0010 pump curve is very close to the b&g 100series.I think all the "00" series housings are the same, but you could drop an e-mail to Taco, to be sure.
  • kirk42
    kirk42 Member Posts: 9
    Thanks

    I will check out the Taco 0010 flow rate or find something compatible to a series 100 pump.Whats your thoughts on keeping the circ on the supply? 
  • Paul48
    Paul48 Member Posts: 4,469
    edited January 2014
    Supply

    It belongs on the supply. I'd leave it there.Still got the 100 series? I think its housing is only 1/8" longer, flange to flange. If nothing else, it would confirm the problem.Better question...did you have the foresight to use isolation flanges or valves with the new circ?
  • kirk42
    kirk42 Member Posts: 9
    B&G

    I have a new 100 pump I'll install this weekend,like you said it will fix the problem or take it off the possible cause list. I've installed dozens of these boilers on monoflo systems without a hitch but this must be that 1 in 100.  Thanks for input I will update this thread next week with the results.
  • kirk42
    kirk42 Member Posts: 9
    Isolation flanges

    And yes I have 2 full port ball valves,1 before circ and one right out of boiler to make future circ changes easy,just didnt think it would be so soon haha.  Thanks again
  • Paul48
    Paul48 Member Posts: 4,469
    Good Luck

    Keep us posted. There have been a couple other (twin) posts, just like yours.Same conditions...mono flow, replaced b&g 100.
  • Jake from state farm
    Jake from state farm Member Posts: 12
    edited January 2014
    I wonder what the return temp Is?

    If the supply is 190. And what is supply and return water temp at each convector? Hope you can figure it out in short order. Good Luck!
  • kirk42
    kirk42 Member Posts: 9
    Success

    Took a compressor with me and before I changed pumps I blasted each convector radiator with 100 psi with much success. Seems even though I vacuumed and brushed each rad.and they appeared clean and clear there was a 50 yr build up of dust and pet hair on top of each individual 1/2" pipe between each fin on the rad.

    Hard see until I blew it away. Rad.and room temp increased nicely and have not had a callback since January.   Thanks for all your help.   Hope this saves someone some time in the future.
  • icesailor
    icesailor Member Posts: 7,265
    edited March 2014
    Air compressors are a beautiful thing:

    Air compressors are a beautiful thing. I never left the shop without mine. I have one here with me. They don't have to be heavy of big.

    They are really handy for blowing animal hair and dander out of the air inlets of oil burners.

    There's no limit to the handy things you can find for them to do.



    Too many people look for complicated solutions to simple problems.

    I always look for a simple solution to a problem and go from there.

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