One sign of trouble with an electric steam boiler or electric water boiler can be discovering the boiler suddenly fails to deliver at the appropriate pressure or temperature.Discovering why isn't always a simple job. You may have had a heating element fail. Because the heating elements for electric system are located where they will be most effective, inside the vessel, performing a visual inspection isn't usually a practical first step in troubleshooting. Fortunately, for a trained service person checking the function of a heating element for electrical continuity can be done in just a few steps with a minimum amount of equipment. An untrained service person may jeopardize their safety and should not attempt doing electrical service.
Trained qualified service people may examine the boiler by first Turning OFF the electrical supply to the boiler at the service panel and at the boiler.
Open the wiring access panel on the boiler with a key.
Set the multimeter to the proper range and test voltage on the incoming wiring.
Check the voltage from all power leads to ground.
If the reading on your meter is anything other than zero, stop immediately. Check the breakers in the service panel. If the breakers are off and the meter is still getting a nonzero reading, repair the problem before performing any other testing, service or repair.
Once the power is assured to be cut to the boiler open the access panel to see the heating element contactors. The photo shows four typical contactors.
If you are not sure what the ohms should read on your meter contact the factory or seller of the boiler. The expected value should be for a "strapped" element. Select an ohm reading of 100 or 200. Contactors often serve only one element not always and this could alter expected ohm values.
Touch each probe to separate wires leading to the element as the photo shows. Be sure to touch the connections on the underside wires of the contactor
and read the meter's results. Ideally, this should be close to the expected value but may be off up to 10%. A zero or infinity reading indicates a
bad element. Reimers can get you replacements fast for 1 and 3 phase boilers.