Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

A Circulator Is Not A Pump

HeatingHelp
HeatingHelp Posts: 464
edited September 2020 in THE MAIN WALL
A bicycle pump is a pump. So is an oil pump on an oil burner. When those machines start, you expect to get a pressure on the outlet side of the pump that’s greater than the pressure on the inlet side of the pump.

A circulator is different because it’s working within a closed, pressurized hydronic system. It doesn’t have to lift the water to the top of the system because the water is already up there. The circulator doesn’t lift anything; it circulates. It’s very similar to the motor on a Ferris wheel.

Read the full story here

Comments

  • PETE_38
    PETE_38 Member Posts: 4
    As I remember pumps produce flow not pressure, resistance to flow produces pressure.
    I believe the circulator is a pump.
  • Jamie Hall
    Jamie Hall Member Posts: 17,007
    Nice. Black marks on the walls reminds you of hydronic heat? Um... well... OK! And for @PETE_38 , yes, technically a circulator is a pump, but they are built with distinctive characteristics and it would be quite wrong to substitute one for another. As to flow vs. pressure, pumps produce a pressure difference, which in turn produces flow. They will still produce a pressure difference, whether there is flow or not. It's a little easier to demonstrate this with a piston pump, as they can generate much higher pressures, but it's pressure first, driving flow. I can think of lots of examples of this.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • unclejohn
    unclejohn Member Posts: 1,749
    Try lifting water up a pipe from a pond with a taco 007 and see what happens.
  • schreib
    schreib Member Posts: 125
    You make a good point about circulation, but if a rotating impeller creates a pressure differential . . . it IS a pump. Fluid will not move without a pressure differential or height differential. Pumps move fluids for BOTH reasons. There are many types of pumps: Positive displacement and centrifugal pumps cover 90% on the market. However, just because a CENTRIFIUGAL pump works to move water in a closed circuit does NOT make it a circulator. This type of pump is NAMED a circulator by marketing people responsible for selling low pressure head differential, centrifugal pumps to the HVAC industry. It is THAT simple.
  • Jamie Hall
    Jamie Hall Member Posts: 17,007
    To me -- being something of a pedant -- a centrifugal pump designed to be a circulator (it is not just marketing hype) is rather distinctive: it has, almost universally, a characteristically low, flat characteristic curve. Translation: the change in pressure differential with change in flow, which is inherent in all pumps which are not positive displacement, is relatively small (don't confuse this with constant flow or constant pressure, which is accomplished by varying the pump speed). This characteristic is achieved by the design of the impellor and diffuser of the pump.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zman
    Zman Member Posts: 6,957
    This is a little like when people get all worked up over politically correct terms. As long as everyone understands the conversation and no one is intentionally insulting someone, I am good with it.

    I have trouble not calling a big hole in the street with a steel cover a manhole. Probably because only a man would be stupid enough to go into one.

    Circulatory and pumps are different to professionals, the terms can be used interchangeably when talking with a layman. Oh shoot, I did it again, I mean Lay"person" ;)
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Dave H_2EdTheHeaterManHomerJSmith
  • Labenaqui
    Labenaqui Member Posts: 21
    edited September 2020
    Not mentioned is the innate high bypass feature of a volute driven hydronic circulator at rest. We have demonstrated this attribute as a heating continuity feature upon circulator failure on our "Beta Sites".
    Our recently patented "Neo-Gravity Hydronic (FHW) Heating Appliance(TM)" utilizes this attribute along with Delta-T Distribution Management to minimize energy consumption (8-13 Watts, typ.) in powered operation as well.
    Natural (Gravity) Convection is always there, whether we opt to use it or not.
  • mike585
    mike585 Member Posts: 8
    Pumps do work on a fluid. Pressure and flow depend on pump characteristics such as volute size and shape, speed, etc, and system characteristics. A circulator is a pump. When I worked in a nuke plant we had reactor coolant pumps in closed loops of pressurized water. They would be circulators given your definition. No difference.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,345
    PETE_38 said:

    As I remember pumps produce flow not pressure, resistance to flow produces pressure.
    I believe the circulator is a pump.

    I Believe that Pete missed the point.
    a PUMP on a closed system is called a circulator because the "head pressure" does not need to account for "Static Pressure"

    "Literary License" is used to make a point, however, the "Pumps" used to circulate water in a closed system can be far less powerful than one used to get that same water to fill up a swiming pool that is located on the roof of say... a hotel building.

    I know for a fact that a circulator pump in a 5 story building has a head pressure of less than 8 feet even though the top radiator is over 45 feet above the circulator pump. In that same building, there is a Water Pump that produces over 65 ft of head pressure to get the water to the pool on the 5th floor.

    Sometimes we can't see the forrest for the trees, me included. I just learned that many of the Wallies I thought were "Expert Posters" are not in the Trades, but are hobbiests with systems of their own that allow them to help others. Cudos to them!

    Ed
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • PETE_38
    PETE_38 Member Posts: 4
    It’s a pump, variable displacement type.
  • PerryHolzman
    PerryHolzman Member Posts: 234
    Its a pump. Just with low pressure head capabilities.

    In the US Navy and in Power plants (not to mention Engineering School - I'm a mechanical engineer by training)... Circulating water pumps are common for cooling condensers, coolant system loops, Reactor Cooling in Pressurized Water Reactors (PWR), etc. They just have a low pressure head.

    You cannot move water or any gas without 1st creating a pressure differential large enough to overcome the system resistance. It takes a pump to do that.

    Have a great day,

    Perry
  • unclejohn
    unclejohn Member Posts: 1,749
    It's a circulator. It is not interchangeable with a pump. You can not replace it with a pump that sits on the side of a cooling tower now can you. I mean you could but you would soon find out you have two very different things.
  • Jamie Hall
    Jamie Hall Member Posts: 17,007
    It's all semantics, folks. A pump -- a very general term, by the way -- is any device intended to create a pressure differential in a liquid (so as to distinguish it from a fan or blower). A circulator is a particular type of centrifugal pump. So is a ten stage deep well turbine. So is... It really does help to call a particular class of pumps circulators, as we all know what we mean (I hope). But for the fussy, it is also good to remember that a circulator is a member of the class centrifugal pump, which in turn is a member of a the general class hydrodynamic pump, which in turn is a member of the general class pump.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ratio
    ratio Member Posts: 2,918
    Y'all are missing the point. @DanHolohan can talk to engineers, who know that a circulator is a pump, and a homeowner who doesn't know the difference between a pump and a circulator. Not a lot of people live with a foot in both camps.

    Dan (please forgive the familiarity), I enjoy your prose. Keep speaking to us!

  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,425
    Thanks for getting it, @ratio
    Retired and loving it.
    heathead
  • unclejohn
    unclejohn Member Posts: 1,749
    A jet engine and my lawn mower engine same thing right?
    Zman
  • hot_rod
    hot_rod Member Posts: 15,003
    And to add more fuel to the fire 🔥 , there is really no such thing as head pressure.

     Got a pumper to put out the fire😉

    What about a circulator pump? Covers both bases.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jamie Hall
    Jamie Hall Member Posts: 17,007
    unclejohn said:

    A jet engine and my lawn mower engine same thing right?

    Insofar as they are both internal combustion engines, yes... otherwise, I sort of hope not!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Larry Weingarten
    Larry Weingarten Member Posts: 2,278
    Hi, whether it's a jet engine or a lawn mower engine, the perspective from that blade of grass is probably a touch of apprehension. Not to try to put words in anybody's mouth, but I imagine Dan was sharing a different perspective also, in order to help people think and see the difference clearly. Good not to lose sight of that goal. I think perspective is a very powerful tool to carry around.

    Yours, Larry
  • PerryHolzman
    PerryHolzman Member Posts: 234
    Just put a differential pressure gauge across your "circulator" and you will see that it indeed increased pressure (even if that is measured in "Inches of Water" and fully meets the definition of a pump.
  • ChrisJ
    ChrisJ Member Posts: 11,966
    This might be the most painful thread I've read on this forum............Dan deserves a hell of a lot more respect than this.

    The entire point was the "pump" is moving a continuous loop, just like a belt or a bicycle chain. It's not lifting water. It's not behaving like a well pump. It's rotating a huge loop, what goes up goes back down etc. Of course the pressure on the outlet is higher than the inlet, otherwise nothing would move.

    The point was to explain what it's doing to those who do not know or understand, not define a word.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    SuperTechratioLarry Weingarten
  • Steve Minnich
    Steve Minnich Member Posts: 2,673
    There’s head added and head loss. No head pressure. The circulator is the only thing that adds head. Everything else plays a part in head loss. Head loss and pressure drop are not the same thing. 
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • Steve Minnich
    Steve Minnich Member Posts: 2,673
    Oh, and I interchange the terms all the time. 
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
    Zman
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,345
    I this the same as the difference between Finnigan pins and Kronston valves? And which one are you supposed to use to check the blinker light fluid in your car?

    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,425
    I think you're supposed to use a pump to inject the blinker fluid.

    I could be mistaken.
    Retired and loving it.
    EdTheHeaterMan
  • RobD739
    RobD739 Member Posts: 2
    The Taco 007-F5 circulator pump is one of the industry’s top-selling hydronic circulators, and for good reason.
  • RobD739
    RobD739 Member Posts: 2

    RobD739 said:

    The Taco 007-F5 circulator pump is one of the industry’s top-selling hydronic circulators, and for good reason.



    That's a Taco marketing statement. (Circulator Pump) 👍
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,209
    It's the same pump/circulator. The difference is in it's application
  • Jersey2
    Jersey2 Member Posts: 50
    They call the water circulator in a car a water pump.
    I'm not a plumber or hvac man and my thoughts in comments are purely for conversation.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 2,345
    Jersey2 said:

    They call the water circulator in a car a water pump.

    But that is where the automotive industry is all wrong! See Dan's comment about the type of pump they use for blinker fluid.
    Edward Young
    Retired HVAC Contractor from So. Jersey Shore.
    Cleaned & services first oil heating system at age 16
  • HansonG
    HansonG Member Posts: 10
    A pump becomes a circulator when it's in a closed system and it's discharge is routed (eventually) to its intake. Circulator, as in a CIRCLE. A pump is not a circulator when its intake isn't fed by its discharge. And I'm not an engineer or in the hydronics trade- just a guy who installed his own system which still works fine after 18 years.. I'm sure someone will want to chew on the details.. Have fun!
    EdTheHeaterMan