Water heater repair

Our water heater was doing something weird. A valve on the side, with a tube running down from it was leaking very hot water onto the floor. We turned off the water to the water heater to prevent a major catastrophe.

According to the owners manual, the valve is a safety valve that opens up if too much pressure builds up in the water heater. This happens if the water overheats and can be very dangerous. 55 gallons of almost boiling water could drain onto the basement floor.

My particular water heater has two heating elements, an upper and a lower, each one has it’s own thermostat. The upper thermostat also has an over temperature sensor, like a circuit breaker, but heat triggered. It had tripped because when I pressed the reset button, it clicked.

I was concerned this happen again, so I monitored the water temperature. After a few hours, the water became unbearably hot, even on the lowest settings.

I decided that something must still be broken, and turned off the water. I also switched off the water heater at the circuit breaker. The circuit breaker was labeled by the prior owner, so it was easy to identify.

My appliance parts specialists suggested I bring in both thermostats, so they can find the correct replacements.

Taking photos before unscrewing anything, I removed both thermostats. They were easy to tell from the heating units because they were plastic boxes pressed onto the water tank, where the heating elements looked like giant bolts, screwed into the water tank, with wires coming out.

While the thermostats were out, I noticed that the temperature knob for the upper unit made a distinct click when turned, while the lower unit turned very smoothly. The parts specialist couldn’t tell me which one was broken, and only had the lower unit in stock, which I purchased for $17.00. The upper thermostat, I could order for $34.00. I decided that I would try just the lower unit, then order the upper unit, if needed.

After replacing the lower unit and reinstalling the upper unit, I turned on the power. A few hours later the water temp stabilized. The repair was a success.

Apparently, thermostat failures are pretty common. I found both the upper AND lower thermostats at my local hardware store, for about 1/2 price.

So here is what I learned:

  • Turn off the water
  • Turn off the electricity
  • Clicking thermostats that feel like they might be broken may actually be a good thing
  • Smooth turning thermostats may be a bad thing
  • Check your local hardware store, before your parts specialist.
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A computer geek with a taste for sustainable living, organic food, green products, buying local, woodworking, bicycling, running, yoga, recycling and doing-it-yourself.