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Hot water heater pump temperature controller

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Ken123
Ken123 Member Posts: 17
in THE MAIN WALL
Looking for a temperature controller (RTD input) modulating output 120 VAC to speed drive a small hot water pump, preferable all in one except the pump.

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  • Ken123
    Ken123 Member Posts: 17
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    Ken123 said:

    Looking for a temperature controller (RTD input) modulating output 120 VAC to speed drive a small hot water pump, preferable all in one except the pump.

    Sorry the controller should not be a switch or on/off control,
  • hot_rod
    hot_rod Member Posts: 22,158
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    Are you trying to maintain a certain temperature on a domestic hot water recirculating loop?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Ken123
    Ken123 Member Posts: 17
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    hot_rod said:

    Are you trying to maintain a certain temperature on a domestic hot water recirculating loop?

    Yes
  • ratio
    ratio Member Posts: 3,629
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    Sounds like you're looking for a ΔT pump. IIRC Taco, Grundfos, etc. all make one.

    I don't know how successful you'll be trying to add ΔT to an existing pump. 120V single phase motors just aren't well suited to speed control.

  • Ken123
    Ken123 Member Posts: 17
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    ratio said:

    Sounds like you're looking for a ΔT pump. IIRC Taco, Grundfos, etc. all make one.

    I don't know how successful you'll be trying to add ΔT to an existing pump. 120V single phase motors just aren't well suited to speed control.

    Thanks.

  • hot_rod
    hot_rod Member Posts: 22,158
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    Most all the solar controllers on the market could run a setpoint function.

    The can modulate any non ECM circulator. It's basically a triac relay that does the speed control, a "wave chopper".

    I think all the pump manufacturers have a complete system ready to go for DHW recirc with VS control?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Ken123
    Ken123 Member Posts: 17
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    hot_rod said:

    Most all the solar controllers on the market could run a setpoint function.

    The can modulate any non ECM circulator. It's basically a triac relay that does the speed control, a "wave chopper".

    I think all the pump manufacturers have a complete system ready to go for DHW recirc with VS control?

    Wave choppers have several concerns: Please see https://blog.orientalmotor.com/speed-control-basics-speed-control-methods-of-ac-induction-motors
  • Ken123
    Ken123 Member Posts: 17
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    Ken123 said:

    hot_rod said:

    Most all the solar controllers on the market could run a setpoint function.>
    So far the only controllers I could find are on/off but will search further. Thanks for working to help me.

  • Ken123
    Ken123 Member Posts: 17
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    hot_rod said:

    Most all the solar controllers on the market could run a setpoint function.

    The can modulate any non ECM circulator. It's basically a triac relay that does the speed control, a "wave chopper".

    I think all the pump manufacturers have a complete system ready to go for DHW recirc with VS control?

    So far the solar controllers I could find have on/off control and will search further. Thanks for helping review.
    Daveinscranton
  • Derheatmeister
    Derheatmeister Member Posts: 1,545
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    'Wave choppers" better known as PWM have been inplemented for a long time with out any issues to (Single phase) motors.
    Small wet rotor circulating pumps use this technology in conjunction with PID to accive very precise temperatures.
    One of the first european Pump manufactureres to inplement this was Wilo followed by Grundfos...Tekmar Makes standalong PWM controls..
    Sometimes a simple Anti scald valve can also do the job as a KISS concept.. ;)
    rbphhc
  • pecmsg
    pecmsg Member Posts: 4,862
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    TACO Viridian VT2218
    Can operate off of Delta T
    Derheatmeister
  • Derheatmeister
    Derheatmeister Member Posts: 1,545
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    pecmsg said:

    TACO Viridian VT2218
    Can operate off of Delta T

    I think Ken123 is looking for a Domestic Hot water situation..I think the Taco VT2218 circ pump is to be used only in closed loop systems... Not for domestic..
  • SteveSan
    SteveSan Member Posts: 235
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    @Derheatmeister you are correct, • Equipped with a cast iron casing and should be used for closed loop systems only
  • pecmsg
    pecmsg Member Posts: 4,862
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    Do they make it in Stainless?
  • Ken123
    Ken123 Member Posts: 17
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    Derheatmeister said:

    'Wave choppers" better known as PWM have been inplemented for a long time with out any issues to (Single phase) motors.
    Small wet rotor circulating pumps use this technology in conjunction with PID to accive very precise temperatures.
    One of the first european Pump manufactureres to inplement this was Wilo followed by Grundfos...Tekmar Makes standalong PWM controls..
    Sometimes a simple Anti scald valve can also do the job as a KISS concept.. ;)

    With PID control seems like a good application and at low speeds the PID will adjust for low speeds?
  • Derheatmeister
    Derheatmeister Member Posts: 1,545
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    I am a little confused on what the Application is supposed to be for...
    As far as i understand you are trying to contol the Domestic recirc line Temperature ?
    Grundfos makes recirc pumps with a build in thermost(Shuts down once the temp is achieved)..
    Do you currently have a Recirc line ?
  • Ken123
    Ken123 Member Posts: 17
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    No, but may want to make a recerc line if I can work a design. I want to bring hot water from my house gas hot water heater to an heat exchanger and return. I want to measure temperature in my house sent to a temperature controller with PID function. The controller will out to an input of a pump speed driver such as an inverter feeding a pump installed in the water line. The inverter will power the pump.
    tim smith
  • ratio
    ratio Member Posts: 3,629
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    I believe some members have used (previous versions of) these <https://controlresources.com/ac-fan-control-ac-motor-control-smartfan-nimbus/ > for analog control of small circulators.

    What, exactly, are you trying to do? Using any sort of water heater for space heating is often (but not always) a bad idea, but it is always hard to do safely and efficiently.

  • Ken123
    Ken123 Member Posts: 17
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    Yes, I am trying to do as you say. Please share some safety concerns. Thanks
  • tim smith
    tim smith Member Posts: 2,752
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    My favorite way to control a recirc loop is with occupancy sensors in baths and kitchen. If placed appropriately the will come on when you enter room. You could oversize a little to speed up flow. Then they automatically turn off after 2 min of no movement sensed.
    rbphhcTurbo Dave
  • Derheatmeister
    Derheatmeister Member Posts: 1,545
    edited January 2022
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    Ken123 said:

    Yes, I am trying to do as you say. Please share some safety concerns. Thanks

    One concern i have is called Legionnaires' disease.
    It can form in the HX,Expansion tank,waterheater,piping and fixtures...
    Tekmar has a "Flush" cycle build into the program for this kind of operation,(Open systems)
    I highly disagree with this setup as it can have devastating effects on human health if not mantained or operated correctly.
    A friend of mine was infected by it,was hospitalized and allmost died from it.
    Ken123
  • Ken123
    Ken123 Member Posts: 17
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    Derheatmeister said:

    Ken123 said:

    Yes, I am trying to do as you say. Please share some safety concerns. Thanks

    One concern i have is called Legionnaires' disease.
    It can form in the HX,Expansion tank,waterheater,piping and fixtures...
    Tekmar has a "Flush" cycle build into the program for this kind of operation,(Open systems)
    I highly disagree with this setup as it can have devastating effects on human health if not mantained or operated correctly.
    A friend of mine was infected by it,was hospitalized and allmost died from it.
    I studied Legionnaires disease a while back and it is present in the air but cannot harm us because our lungs prevent it from entering deep into the lungs. But if these is a mist the small droplets then can enter our lungs and infect us.

    Legionnaires disease may multiply in the exchanger and enter the Hot water heater giving a higher concentration and when taking a shower the mist may be concentrated with the disease. Thanks

    Derheatmeister
  • Ken123
    Ken123 Member Posts: 17
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    Derheatmeister said:

    Ken123 said:

    Yes, I am trying to do as you say. Please share some safety concerns. Thanks

    One concern i have is called Legionnaires' disease.
    It can form in the HX,Expansion tank,waterheater,piping and fixtures...
    Tekmar has a "Flush" cycle build into the program for this kind of operation,(Open systems)
    I highly disagree with this setup as it can have devastating effects on human health if not mantained or operated correctly.
    A friend of mine was infected by it,was hospitalized and allmost died from it.
    Also brain eating ameba's may get a foothold in the exchanger if the hot water heater is not hot enough.
    Derheatmeister
  • rbphhc
    rbphhc Member Posts: 126
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    Derheatmeister said:

    'Wave choppers" better known as PWM have been inplemented for a long time with out any issues to (Single phase) motors.
    Small wet rotor circulating pumps use this technology in conjunction with PID to accive very precise temperatures.
    One of the first european Pump manufactureres to inplement this was Wilo followed by Grundfos...Tekmar Makes standalong PWM controls..
    Sometimes a simple Anti scald valve can also do the job as a KISS concept.. ;)

    Reviving an old thread. Can you say more about this option, or link to any resources? Thanks very much!
    neilc

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