Announcement Module
No announcement yet.

Diagnosing with multimeter

Page Title Module
Move Remove Collapse
Conversation Detail Module
  • Filter
  • Time
  • Show
Clear All
new posts

  • Diagnosing with multimeter

    Anyone use a digital multimeter to troubleshoot an electric hot water tank?
    I know how to test an element for resistance, and to verify that the unit is getting power, but can the thermostat and high-limit switch be tested also? if so how?
    Disappointingly enough, this wasn't covered in my plumbing class...
    What about tankless water heaters, electric boilers, zone valves, various controls etc. i suppose they can all be diagnosed with the multimeter?

  • #2
    Re: Diagnosing with multimeter

    Manufacturers have a wealth of information available online that is for the most part application specific, A O Smith has a WONDERFUL service manual available online that outlines all of the testing procedures for their water heaters, gas electric, Powervent and more. Yes you can test everything that you listed with your multimeter and other tools. For example A.O. Smiths service manual for residential water heaters can be found here:

    you will have to search for other things for service manuals but they are out there, for themostats and other boiler controls try honeywell's website, for the tankless you will ahve to check the specific manufacturer's website be it Rinnia, Tagaki, or shudder Bosch. I hope this helps and welcome to the forum!


    • #3
      Re: Diagnosing with multimeter

      Thankks wrench spinner, took a quick look thru that AO Smith manual, better and more informative than any textbook....I'll be searching for as many of those as I can find, and building a good technicl library.
      Thanks again


      • #4
        Re: Diagnosing with multimeter

        I won't walk into a water heater job without my multi meter and a set of jumper wires. I even check thermocouples before I replace them on the vapor lock models. The old models are easy enough to change the thermocouples. The A.O Smith manual will work for the other models maybe some small differences but nothing major.