Troubleshooting your Solar Hot Water System

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Troubleshooting your Solar Hot Water System

Category : ECA News , Solar Hot Water

Having trouble with your solar hot water system? Here are some potential problems and solutions.

No Hot Water – Check that the water heater circuit breakers are in the “ON” position.  Turn the switch on the timer to “ON” and wait 15 minutes.  If the water doesn’t heat up, turn the timer switch and water heater circuit breakers off and remove the top access cover on the tank with a Phillips screwdriver.  Remove the insulation.  Check that the thermostat is set between 110 and 120.  Press the red button.  You should hear a click and the water will start heating when you turn the power back on.  You may be able to hear it boil.  If the button wasn’t popped out, call a service person or contact ECA for more info.

No Hot Water in the morning or a very high electric bill – Carefully touch the solar pipes or fittings above the solar tank (they are the smaller pipes) in the evening after 7 PM. They should both be cool or one just slightly warmer. If one is very hot and the other cool, it means that the hot water is rising up to the panels at night, cooling off in the cool night air, and cooling off the tank. This is usually caused by a failed check valve or incorrect design. Call a service person or contact ECA for assistance. If both pipes are hot, check to see if the pump is running. If it is, go to the paragraph below.

Pump Running at night – Check that the solar controller switch is set to “automatic.”  If it is, and the pump runs continuously at night, call a solar repair person or ECA. There is most likely a problem with the solar sensors, wire, or controller.  If the pump only comes on occasionally at night, perform the test described in the above paragraph.

Knocking noises heard in the tank – You probably have the solar high limit control set low and the pump is shutting off when the sun is still shining. This causes water in the panels to boil and send steam down into the tank. Set the high limit on your controller all the way up and have an “automatic cooling thermostat” installed that will leave the pump running into the evening to cool the tank down. You could also have a tempering valve installed if you need to limit the temperature of the water. Another solution is to have a 40 or 50 gallon tank added to your system to absorb that extra hot water and save it for a rainy day. If you need more info contact ECA.


Robert Karl Skoglund

May 18, 2012 at 2:02 am

The thermostat on the top of the outside solar hot water heater reads about 20 degrees lower than it should be. It is 55 outside but it reads 35. Do these things readjust themselves when they have been asked to run at a temperature that is lower than what would make them efficient? I’m running the water through my cellar floor and it returns very cold. Thank you. Robert Skoglund, St. George, Maine

    Energy Consulting Associates

    June 9, 2012 at 12:49 pm

    Are you talking about 35 Fahrenheit? It should never be that low. The thermometer may be broken or adjusted wrong.