Hot Water Recirculation Loops

Why wait for hot water?

There are three key reasons your customers should want a “recirc” system:

It saves water – It saves money – It saves time.

The average home wastes 11,461 gallons of water per year due to unnecessary wait for hot water to reach showers and faucets. Grundfos offers hot water recirculation technology to meet new construction and retrofit needs.

For new construction

The UP10-16 pump is designed for new home installations with a dedicated return line. The one-piece HWR solution is easily installed at the water heater. This innovative pump comes with an integrated aquastat and timer to meet your customers specific demands.

Potable hot water recirculation

A common homeowner complaint is the long wait for hot water in the bathroom. Frequently, that wait can last for one or two minutes. Toss in a family with several bathrooms, and the potential exists for large volumes of water to be wasted. Our chart with the calculation based on pipe size, length of run, and daily usage indicates 9,855 to 55,115 gallons of wasted water per year (www.grundfos.us/hwr).

Hot water recirculation system applications:

• 24/7/365 constant circulation with a dedicated return line
• Dedicated return line with an aquastat to turn the pump on and off
• Dedicated return line with timed pump circulation
• Hot-to-cold timed circulation with an aquastat to limit the cold water line’s temperature
• Thermal by-pass systems can be motion-sensor, infrared, or manually activated

Why is it important?

Water use:

• An average home over 2,000 square feet has 125 feet of 3/4-inch pipe
• 125 feet of 3/4-inch Type L copper pipe holds 3.14 gallons of water
• 10 draws per day wastes about 31.4 gallons of water
• Over a year, the use equals 11,461 gallons
• 25.2 million homes waste 288,817,200,000 gallons of water per year

Wasted water cost analysis:

• Assume 12,000 gallons water wasted per year
• At $.007 per gallon, that comes to $84 down the drain
• At 82% efficiency, heating water from 55° F to 140° F costs $138.33 (natural gas costs $.01335 per 1 cu. ft.)
• Add yearly sewage treatment cost of $52.79
• The total wasted-water-cost would come to $275.12

The system’s initial cost and fees to install an electrical outlet may seem like a deal-killer. But if you promote the return on investment, your sales will increase. ROI is calculated by dividing the system’s cost into the annual fuel savings. If you project an annual saving of $100 and the system costs $600 installed, the ROI is an attractive 16.7%, which is also a tax-free ROI.

Example 1:
Operating costs for recirculation – constant circulation:

• 33W circulator running 24/7/365 costs $26.60 at $.092 kWh
• Average annual heat loss cost $138.33 (1/2-inch copper tubing covered with 1/2-inch fiberglass insulation)

Annual savings: $275.12 – $26.60 – $138.33 = $110.19

Example 2:
Operating costs for recirculation – timed circulation:

• 33W circulator running 2 hours per day costs $2.22 at $.092 kWh
• Average annual heat loss cost $14.62 (1/2-inch copper tubing covered with 1/2-inch fiberglass insulation)

Annual savings: $275.12 – $2.22 – $14.62 = $258.28

UP10-16B5/BN5/BU
– for hot water recirculation with return line

Technical data

Flow range: 0 – 2.5 GPM
Head range: 1 – 5 feet
Motor: 25W
Voltage: 1 x 115V
Fluid temperature range: 36°F (2°C) to 203°F 95°C
Max. working pressure: 145 PSI
 

Flange to flange length:
UP10-16B5/BN5 3-1/8 inches
UP10-16BU 4-1/3 inches
Pump housing: Brass MS 58
 

Connection type:
UP10-16B5 1/2-inch sweat
UP10-16BN5 1/2-inch FNPT
UP10-16BU GF 125 union – 1-4” NPSM

• Standard features: 5 foot line cord w/plug
• Optional features: Timer, aquastat