Presentation on theme: "Hot Water Recirculation Pumps. Tim Pehl Outside Sales Rep For Dawson Company. Outside Sales Rep For Dawson Company."— Presentation transcript:
Hot Water Recirculation Pumps. Tim Pehl Outside Sales Rep For Dawson Company. Outside Sales Rep For Dawson Company.
2 Topics Scenario. Scenario. How a recirculation Pump works. How a recirculation Pump works. History of recirculation Pumps. History of recirculation Pumps. Latest technology. Latest technology.
3 Scenario. We get up in the morning and we turn on the hot water to take a shower. hot water to take a shower. we put our hand into the stream of water to we put our hand into the stream of water to check the temperature, and it is cold. check the temperature, and it is cold. We may wait for a full 60 seconds, or longer, We may wait for a full 60 seconds, or longer, before we can step in and take our before we can step in and take our shower. shower. Why?? Why?? We don’t have a recirculation pump! We don’t have a recirculation pump!
Scenario. Dead end piping WH Normal Hot Water Operation: Last hot water use at night time around 11:00pm Normal Hot Water Operation: Last hot water use at night time around 11:00pm Water heater output: 130°F Hot Water DHW Pipe run: 100 feet ¾” Copper Pipe WH Normal Hot Water Operation: Following morning at 7:00am Water heater output: None – Existing water cools to 60°F DHW Pipe run: 100 feet ¾” Copper Pipe Traditional non-recirculated system
Scenario. Residence is three bedroom with four occupants and two baths. Water heater is approximately 60’ from master bedroom Hot water supply line from water heater is un-insulated ¾” copper pipe Assume the following volume of hot water wasted per day: Master lavatory1.5 gal fixture2.625 gal wasted/day Second bathroom lavatory1.5 gal fixture7.5 gal wasted/day Master Shower2.5 gal fixture15 gal wasted/day Second bathroom shower2.5 gal fixture2.625 gal wasted/day Kitchen Sink2.5 gal fixture12.5 gal wasted/day Water consumption is based on the system operating 350 days per year Total water wasted in a year is 14,087 gallons based on total water wasted of gallons per day
Scenario. How Much Water is 14,000 Gallons?
Scenario. Return line added with Circulator. 60psi WH Normal Hot Water Operation: Following morning at 7:00am System with hot water recirculation
Induction Vs Permanent Magnet Induction Motor No magnet on rotor Stator coils create magnetic field which induces current into rotor The rotor currents interact with the rotating magnetic field which causes a rotational motion on the rotor. Because the magnetic and electric fields are out of phase (slip), there are greater current requirements and current losses. Permanent Magnet Motor Permanent magnet on rotor Eliminates the requirement for input power to magnetize rotor Stator coils generate a rotating field to induce the permanent magnet to rotate Motor is microprocessor controlled to keep the stator current in phase with the magnets of the rotor. The lower current requirement and no “slip” result in greater efficiency.
Comparison: Spherical Motor vs. Canned Motor Key Advantages Simplicity – just one high precision part No shaft, no bearing bushings Self-aligning rotor Long term quiet and trouble free operation No start-up problems
System Curve System CurveSystem Curve
Recirculation pump with ECM technology Duty Point 5 Watts Duty Point 40 Watts Flow (GPM) Flow (GPM) Head (FT) System Curve 88% LESS ENERGY CONSUMPTION e 3 -4 Variable speed option can reduce smallest pump energy consumption even further
One Switch - Two Options Every ECM circulator has a switch installed- you have the choice A.Variable Speed Control B.Variable Temperature Control(68 to 158 Deg.F.) Variable Temperature Control Variable Speed Control NEED PIC
Options Most pumps come standard with constant speed. Power cords are sometimes optional. Variable speed. Temperature control. Time clocks
What if I don’t have a return line? Autocirc 14 watts
But I have a Tankless water heater Sizing a pump for Tankless water heaters is the same as a tank type. However, a larger pump will be needed as the Tankless units have a heat exchanger inside that produces a higher pressure drop.