KSDB-40-ST Drainback Solar Water Heating System

Drainback system, one KS-40 4x10 collector and 80gal storage tank, for 3 or 4 occupant residence

This drain-back solar water heating system is designed to maximize solar heating savings for a home occupied by 3 or 4 adults. This KSDB-40 converts any water heater into a solar powered water heater using a DBHX Drainback module.

This system:

• connects to an existing water storage tank
• provides automatic freeze protection
• works well in most climates
• does not need propylene-glycol to protect from freezing temperatures
• low maintenance

List identifying parts in the diagram

• 1. Watts 530L pressure relief valve for drainback reservoir loop
• 2. 10 k sensor
• 3. KS-40 (4ft by 10ft) solar panel
• 4. Watts 70A anti-scalding mixing valve
• 5. Pentair In-Line temperature gauge
• 6. Watts T/P valve
• 7. Pentair flow meter
• 8. Taco 006-B4 circulator is pumping water from the bottom of the solar storage tank through the heat-exchanger into the top of the solar storage tank.
• 9. Goldline GL-30 differential solar controller
• 10. 4500 watt electric heating element (optional)
• 11. 80 gallon Solar Storage tank installed next to existing electric or gas water heater.
• 12. internal heat exchanger inside the DBHX drainback tank, surrounded by solar-heated water coming from the solar panel.
• 13. Taco 009-BF5 pushing reservoir water up to the solar panel
• 14. 8 gallon water reservoir
• 15. 10K sensor

The KSDB-40-ST Solar System includes:

• one KS-40 Solar Panel with two mounting feet hardware kits
• one DBHX1062 Drainback module, which includes:
  • one 8 gal tank with heat exchanger,
  • one Taco Pump 006-B4,
  • one Taco Pump 009-BF5,
  • one Goldline GL-30 differential controller with two 10k sensors
• one Pentair/Letro 1-10 gpm flow meter model LDF357B
• one Pentair/Letro SL-2DW3 inline temperature gauge
• one Watts 70A Tempering Valve
• one Watts 530L-75 3/4in adjustable pressure relief valve
• one Watts 100XL4 T/P Temperature and Pressure Relief valve (for the Rheem tank)
• one 80 gallon, 4 port Rheem water storage tank

How the KSDB system makes hot water from the sun

The GL-30 Differential controller (10) starts both Taco pumps (8 and 13) when the controller detects useful solar heat available at the sensor (2) attached to the solar panel (3). Useful solar heat is available when the temperature in the solar panel is significantly higher than the temperature of the water at the bottom of the storage tank measured by a sensor (15) at that location.

The Taco 009-BF5 (13) begins circulating the 8 gallons of water in the DBHX drainback tank's reservoir (14) by pumping it through the solar panel on the roof and back into the reservoir tank in a continuous loop. The water heats up as it passes through the solar panel. Note: The DBHX tank's internal heat-exchanger coil (12) is immersed in the tank's resevoir water.

The Taco 006-B4 (8) begins circulating the potable water from the larger Rheem solar water storag tank (11) through the DBHX's internal heat exchanger (12) and back. Heat transfers via the heat-exchanger from the warmer solar heated water in the DBHX's reservoir (14) to the cooler potable water in the heat-exchanger coil (12).

Both pumps continue circulating fluids and the controller continues monitoring the temperature between the solar panel and the solar water storage tank.

Automatic KSDB operations

The controller (10) stops the pumps when it senses useful solar heat is no longer available. There is no useful heat to collect when the temperature at the bottom of the solar storage tank reaches about the same temperature as the solar panel, ie when there is not a significant temperature difference (differential) between the solar panel and the solar water storage tank. The controller starts the pumps again when useful heat is available.

The ON-OFF cycle of the pumps continues throughout the day maximizing the availability of solar heated water. At night the solar system stays off. The system activates the heating cycle again the next day, when the controller senses direct or indirect solar light heating the solar panel.

Installation considerations

The KSDB-40-ST solar water heating package is designed for a family of 3 or 4 adults. The system can be expanded to accommodate 8 to 10 adults by adding more solar panels and more water storage capacity. Consult with one of our specialists about how to scale up the system

The KSDB drainback solar tank can convert any water heater into a solar powered water heater by installing the DBHX drainback tank to the drain port and pressure relief port of your existing hot water tank.