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Replacing Circulator Pump

Aecom87
Aecom87 Member Posts: 3

I have to replace one circulator pump on a 3 pump system however I have No pump isolation valves. So I guess I have to drain the entire system from the bottom of the boiler? I only have zone vents above the pump with hose cocks, no vents on baseboard. Is this correct??

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,242

    Sorry. This is not going to be fun, but yes you have to drain below the pump.

    Maybe. First off, what part of the pump needs replacement? Make sure that it isn't something out of the water. Or, if you fancy getting wet and are replacing like for like and it's a flanged pump, you might get away with unbolting the old pump completely, arranging to separate the pipes just a bit — quarter inch would do — and with a helper separate the flanges, pull the old pump out and slip the new one in. You'll get drenched.

    Or… just drain it and go through the pain of purging the system when you get it hooked up again. Might be easier!

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Aecom87
    Aecom87 Member Posts: 3

    Thank you Jamie, so either do it on the fly by getting soaked or unfortunately drain the whole system. Thanks for your help

  • HVACNUT
    HVACNUT Member Posts: 6,101

    It's different depending on how the system is piped. If your able to shut off all valves above the boiler and circulators. Shut off the feeder. Shut off the valve to the extrol or expansion tank. Close the caps on any air eliminators. Drain from the bottom of the boiler ONLY until the water stops and there's no more pressure. Then Close the drain valve.

    Prep the circulator first. Make sure the nuts and bolts aren't seized. Remove the wiring from the old one. Do it on the fly. If you get some water, jam a rag in the pipe to give you a few extra minutes if you need it.

    Rewire. Start and check all zones after all valves are open.

    If the air eliminator(s) looks suspect, replace it as well.

  • retiredguy
    retiredguy Member Posts: 968
    edited October 7

    By the way, whose pump is it, the name brand, the model and just what is wrong with the pump. Please include a picture or two of the pump. Some pumps have built-in shut off valves.

    Intplm.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,796

    You can replace the "motor only" of some older pumps. If it is a wet rotor pump like the Taco 00 series pumps or the Grundfos UPS series pumps, you can leave the housing bolted to the pipes.

    1. Take the pump motor and impeller (cartridge) off of the housing (that has the flanges) of the new pump.
    2. Have the O ring or gasket ready from that new pump also
    3. remove the old pump motor and impeller off of the old pump (in the fly or dry either way) and put the new pump motor and impeller on the housing, be sure that the O ring or gasket is lined up properly.
    4. Bolt the new motor housing in place.

    I have found that is ofter an easier repair than trying to line up and bolt together the two separate flanges and getting the flange gaskets set properly.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    SuperTech
  • Aecom87
    Aecom87 Member Posts: 3

    it’s a B&G “little red booster pump” flanged. No longer available so I bought a B&G replacement. Motor is extremely noisy, this pump has oil ports which have been used. I can’t just replace motor using same pump casing because of different bolt holes.

    EdTheHeaterMan