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Here we explain how to test and repair an electric hot water heater that is not heating at all or is not producing enough hot water. We start with simple basic checks and then move to testing and replacing bad controls or bad water heater elements.

This series of articles describes how to inspect, operate, diagnose, and repair electric hot water heaters. The articles at this website will answer most questions about electrical water heaters as well as many other building plumbing system inspection or defect topics. Reproduction of this web page electronically at other websites is prohibited.

Also see TIMERS for ELECTRIC WATER HEATERS. If you cannot find information you need here or if you have comments, questions, suggestions for inspecting and diagnosing water heaters Contact Us

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How to Repair an Electric Water Heater

Tests When there is No Hot Water at All

The cause of no hot water at all coming from an electric water heater might be

1. No electrical power to the heater
2. A water heater timer is installed but is "off" or not working - see TIMERS for ELECTRIC WATER HEATERS
3. Failed high temperature cutoff switch, or high temperature switch is "off on reset" and needs to be re-set - see Electric Water Heater Controls List
4. Both upper and lower heating elements have failed - see Test Electric Water Heater Elements

In this article we discuss these four possibilities in the order we've listed above.

If there is some hot water but it is limited in quantity or temperature, just one of the heating elements may have failed. Scale coating a water heater element can also reduce the quantity of hot water (or cause heating element failure) - a topic we review in more detail at at WATER HEATER NOISES.

If your electric water heater has stopped working entirely, or if it produces less hot water quantity than normal, or the electric water heater produces warm but not hot water, the diagnosis of the water heater problem is pretty easy, and sometimes the repair is easy and inexpensive as well. Here we outline steps to inspect, test, and repair an electric water heater.

Check the water heater for leaks. If the water heater tank itself is leaking, you almost certainly need a new heater. We discuss water heater leaks at Electric Water Heater Inspection Checklist - while you're at it, go through that checklist: while getting your electric water heater working properly you may find and need to correct other defects including some that are important for safety.

Check the circuit breaker or fuse for the electric water heater. The heater is usually fused in the main electrical panel but some electric water heaters may be fed from a separate fuse or circuit breaker box. If the fuse is blown or breaker is tripped, replace the fuse or re-set the circuit breaker. If the fuse blows again or the circuit breaker trips again, do not re-fuse or re-set the breaker as the sysetm is unsafe and you need a professional electrician.

Check the water heater timer: Some electric water heaters are installed with a timer (photographs above) that saves electricity costs by turning off the heater during periods when no one will be using hot water. If a timer is installed for your heater, it might be in its "off" position. Instructions for setting the water heater timer are inside the timer cover. See TIMERS for ELECTRIC WATER HEATERS.

Check the water heater thermostat condition and its internal thermostat control reset switch. Below we show how to find the thermostat control and reset switch for an electric water heater. See Electric Water Heater Reset & Temp Set.

If all of these items check out OK the water heater may have one or both of its heating elements burned out. We discuss finding, testing, and replacing an electric water heater heating element below.

Electric Water Heater Thermostat Location, Adjustment, Settings, & Test or Replacement Procedure

Behind each electric water heater panel you will see electrical wiring, a themostat with a pointer and temperature setting numbers. Turn off electrical power to the water heater before opening the water heater access panels. Otherwise you could be killed by electrical shock. Smart repair people and owners use a neon tester or multimeter to absolutely confirm that electrical power has been turned off before ever touching electrical components. We removed the upper panel metal cover (two screws), lifted off the styrofoam insulating cover, and revealed the water heater control in our photo at left. If you break or lose the plastic cover that protects the water heater thermostat and heating element electrical connections, a replacement cover is provided with most water heater element replacement kits.

Also located behind each panel is the actual upper or lower heating element. Our photo (left) is the same location as we showed above, but we removed a plastic safety cover to show the electrical connections and other controls available here. From the top of the control you can see Electrical wires bringing power to the heating element A red "reset switch" for the electric water heating element control. Electrical wires taking electrical power out of the thermostat control and into the electrical heating element itself. The electric water heater temperature setting dial. The electrical wires connected to the head of the water heater heating element. If setting the water temperature to a lower setting does not work there is a problem with the control and it probably needs replacement.

Electric Water Heater Internal Reset Switch & Temperature Setting Dial on the Thermostat

Just below we show closeups of the electric water heater internal reset switch (below left), and the water heater thermostat dial that sets the temperature control for (in this case) the upper heating element (since we are looking behind the upper panel on the electric water heater). This water heaer is set to its maximum output temperature, 150 degF. If water leaves a faucet at 150 degF. scalding can occur in about 1 1/2 seconds.

If the electric water heater output water is too hot you can adjust the thermostat to a lower setting. Typical settings are 140 to 160 degF. Beware that any temperature above 120 degF. is scalding and a mixing valve may be needed for safety.

Our two photos above are of the lower heating element on this electric water heater. You can see from the burned and melted plastic that there was a problem with the lower heating element on this unit. But if you see this condition on an electric water heater whose history is unknown, do not assume that this is a current problem. On this water heater we replaced a burned-out bottom heating element several years ago, leaving the burned plastic cover and insulation cover on the unit.

Above are photographs of a replacement electric water heater upper thermostat (including its reset button) and the smaller lower water heater thermostat. Wiring details provided with these water heater controls are at Electric Water Heater Element Replacement.

At links below we continue with more diagnostic testing and repair procedures for electric water heaters, looking at the high limit cutoff switch, the high temperature reset switch, and testing and replacing bad electric water heater electrodes.

Questions & Answers regarding this article

Questions & answers about how to diagnose and repair electric hot water heaters

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

ELECTRIC WATER HEATERS
  Identify Electric Water Heater Parts
  Electric, Gas, Oil Water Heater Efficiency
  Electric Water Heater Checklist
  Electric Water Heater Controls List
  Water Heater Anode & Dip Tube Check
  Hot Water Temperature & Pressure Valve
  Electric Water Heater Repair Guide
  Electric Water Heater Reset Switch
  Electric Water Heater Thermostats
  Electric Water Heater: No Hot Water
  Electric Water Heater Reset & Temp Set
  Test Electric Water Heater High Temp Cutoff
  Test Electric Water Heater Elements
  Timers for Electric Water Heaters
  Replace Electric Water Heater Element
  Drain a Hot Water Heater Tank

• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.

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• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

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