How do I troubleshoot a water-heater?

Question

Lately our hot water has been running out very quickly, a lot quicker than it used to. I have an Whirlpool electric water heater with 2 elements with the top element has a reset switch.

I followed this guide to troubleshoot.

I checked the resistance of each element by removing a wire from each and measuring across the connectors for the element and I got 13 ohms on each one. I restored power to the unit and tested the voltage across the top element by turning the bottom thermostat to the lowest temp and the top one to the highest temp and got no voltage across the top element. I reversed the thermostats and tested the bottom element and got ~240 Volts on the bottom element so I figured the top controls were bad as the article indicated.

I replaced the top thermostat, making sure to label all the wires and reconnect them in the right place, but I'm still getting the same behavior, no voltage across the top element.

Is it possible that the top element is bad? I'm not sure what else to do at this point other than call a plumber.

UPDATE: Apparently it is still not working. I did drain the tank, but the water looked pretty clear and it didn't seem to help any. Here is the extra info on the water heater:

The year is 2002. The hot water runs out about 20-30 minutes. It used to last probably an hour at least. It's a 40-gallon tank.

Answer 1

You may have already done this but not sure from your question. When testing the thermostats be aware that you must test the input and output sides. A thermostat is really just a switch. First be sure you have 240VAC on the input sides across the hot leads and 120VAC from each leg to ground. Now connect to the load or element side across the element and look for 240VAC as you turn on and off the thermostat. If you have an AMPROBE, confirm current flow when the thermostat is turned to the highest temp position, indicating current flow through the element, and conversely no current when the temp is satisfied. If the voltages are good on both sides of the thermostat, but no current, it is safe to assume the element is bad. If you do not get the changes in voltage at the load side when operating the thermostat min to max etc. the thermostat is bad. Have you drained the heater? Large amounts of sediment can indicate fouled elements or a partially plugged dip/transfer tube. Be sure to turn off power before draining and refill the tank before turning electricity back on. You can also find a toll free number for tech assistance online for all Whirlpool products and should be able to reach a real person in tech assistance that will help walk you through it. not sure if they will do that for the user, but they do that for us contractors all the time. Good luck.

Answer 2

Welcome to diy.stackexchange.com =)

Having some additional details might help:

• What model/year water heater do you have?
• Can you be more specific on how quickly the water runs out? A few seconds? A couple minutes? Does it gradually get colder or suddenly change?
• Is the water heater making any strange noises?
• Where is the water heater installed? Inside? Outside? What's the temperature of the environment around it?

It's a little difficult to say but there's some good info here. I've included an excerpt below...

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Possible Causes

• Unit is undersized for water heating demands
• Broken or damaged dip tube allowing cold and hot water to mix in tank
• Faulty plumbing installation has crossed cold and hot water connections
• Faulty electric lower or upper heating element or high or low heating element thermostat.
• A constant supply of lukewarm water during a shower is indicative of a defective upper heating element. Short duration hot water supply during a shower is indicative of a defective lower heating element.

Possible Repairs

• Make sure water heater is not being overtaxed by hot water supply demands. The water heater should have 75% of its capacity as hot water (e.g., a 40 gallon WH should be used for a demand of 30 gallons). To determine required capacity see Calculating Fixture Flow Rates.
• Undo cold water inlet and pipe nipple and remove dip tube. Check condition and replace if required.
• Check for crossed connection by turning off water supply to water heater. Open hot water tap at a faucet. If there is water flow, then the a cross connection exists somewhere.
• Check for a hot water line connected to a cold water connection on the water heater or appliances such as washer, dishwasher, faucet or shower valves.
• Check for proper flame from burner. A natural gas flame should be a bright blue with the tip of the flame having just a tinge of yellow. A propane flame should have a bluish green flame with a tinge of yellow at the tip.
• Check for power and electrical continuity at the lower and upper heating elements. Replace water heating element if necessary. Clear tank of any sediment first. If elements test OK, check for power at upper electrical upper thermostat. If OK check lower thermostat. Replace if necessary.

Answer 3

I just replaced both elements and controls in my unit for $32 from Home Depot. I wish I'd priced that out before bothering with the multimeter.

I don't know your budget, but it seems like the parts are cheap enough that it might be worth the time saved to just replace it all.