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Pumps Suck? (I should know this but I don't)

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  • Pumps Suck? (I should know this but I don't)

    Next week, I'm replacing a boiler in an attic of a 5 story building. 20 years ago all the heat lines were repiped from the basement to the new boiler location. Closed loop, cast iron sectional radiators.

    I see 3 dead soldiers laying in the corner. 2 B&G 100's and a Taco 007. The boiler currently has 2 pumps installed. One on supply and one on return. Never seen that before 5 pumps in 20 years is a problem. New boiler comes with a Taco 007.

    New owner has no case history with this boiler but judging from what I see they have pump issues and possibly some radiators not heating.

    Now my question is should I be looking at a different type of pump that can 'suck' water up to the attic or maybe one with a higher head?

    This is a unique situation for me and just didn't want any problems down the road with this thing. He has several other apartment buildings and I'm looking to develop a relationship with him. I padded the boiler estimate an extra $1000 to cover a specialised pump.

    Trapped air is going to be an issue also...hmmmmm

    Any thoughts?


  • #2
    Re: Pumps Suck? (I should know this but I don't)

    First off , circulators don't technically suck or pump, they circulate. Without pressure on the system the circulator is not capable of moving water. When you do the change out make sure that the circulators are installed on the outlet of the boiler, pumping away from the boiler. They should be installed slightly after the expansion tank and fill valve. The fill valve should be installed at the same location as the expansion tank, typically tee'd in right above it along with the air eliminator. Most circulator failures are due to two things. Either the circ is subjected to too much heat and or it is forced to work agains high head pressures. If the circulators were piped on the return, which is typical because hell, that's where the manufacturer installed them on the packaged boiler, with the boiler mass in the attic they are having to work very hard indeed to pull through all that head. On the feed side they should last for many years.


    • #3
      Re: Pumps Suck? (I should know this but I don't)

      I don't know squat about boilers or what you are doing, but I can tell you that pumps work better at pushing liquids rather than pulling liquids. Don't know if that helps you any at all but just a thought.

      Sounds like a real fun job, hope you have a helper with a strong back.



      • #4
        Re: Pumps Suck? (I should know this but I don't)

        as mentioned. this is a circulating line. not a pump for a water fall.

        what goes up must come down. as water is pushed up, water will fall down. and vica versa.

        think about the fact that we have domestic hot water loops that work great just by thermal dynamics.

        hot water goes up and cold is heavier. thus creating a thermal loop. no pump and instant heat.

        phoebe it is