Monday, October 24, 2011

Hot Water Heater Repair

I was feeling pretty good Sunday morning when I took this picture. Betsy had left me a note saying the hot water heater wasn't working and I had the parts to fix it in that plastic bag - so I thought.

Here's the long boring story...

When I tried to light the pilot light it wouldn't stay lit once I released the reset button. Most likely cause is the thermocouple (copper tube inside the plastic bag). That piece with the tubes and red wire sticking out of it is the burner assembly. The assembly is made up of - the burner (that rusty looking thing), a gas tube for the burner, another for the pilot light, a wire for the piezoelectric spark generator and another copper tube that holds the thermocouple. You have to take the burner assembly out of the hot water heater to remove the thermocouple.

 I was pretty happy that Lowes had a new "universal" thermocouple for about 7 bucks - until I figured out this particular Whirlpool hot water heater has (had) a unique thermocouple.

Little did I know that  this hot water heater is quite famous on the internet for it's thermocouple design. It was the subject of a Class Action, a couple of videos by a home handyman - Left Hand Thread Thermocouple Water Heaters and many web forums documenting Consumer complaints about Whirlpool Water Heaters.

Even though this water heater has quite a reputation on the internet - the people I talked to at Lowes don't know much of anything about the water heater or parts for it. I tried ever place I could think of and no one has this part. Whirlpool told me to tell Lowes I needed the "A" kit - most of the time the answer was - "what"? "You need A kit?" The Lowes in Monroe told me they had the "B", "D" and "G" kit but no "A".

 It's pretty disappointing to me that two brands I've associated with quality products - Whirlpool and Maytag have ended up being not so great. This water heater has worked fine for 6 years so I can't complain too much. The Maytag Performa washing machine (another Lowes purchase) would walk across the basement since it didn't have an out of balance switch - I was glad when it quite working for good. We rolled the dice and bought a Kenmore that's working fine (fingers crossed).

 This water heater has a 6 year warranty on it. The manufacturing date was the August 2005. Since I didn't have the original receipt and never registered for the warranty, the warranty runs from the manufacturing date.

Whirlpool doesn't make water heaters - they just put their brand on them. This water heater is assembled in Tennessee by US Craftmaster aka American Water Heater. I'm getting the new improved thermocouple overnight from the manufacturer in Tennessee. It should show up Tuesday afternoon. Even though I was a member of the class (for the class action suit), Whirlpool told me they won't give me the new improved thermocouple since my heater is out of warranty. If I had most any water heater than this I'd be able to fix it with a 7 dollar part - I'm paying 65 dollars for the part and overnight shipping from Tennessee. There's no local source.


A thermocouple is a device made of two dissimilar metals that converts heat into electricity. Using this property, the water heater thermocouple senses when the pilot light is lit and sends an electrical signal to the gas controller allowing gas to flow. The thermocouple sits in the pilot light flame on a gas hot water heater and outputs a small voltage (20-30 millivolts) when it's heated by the flame.

If you've ever lit a pilot light and wondered why the directions tell you to hold the "reset" button down for a minute - it's because you need to heat up the thermocouple so it generates electricity. The reset button bypasses the thermocouple but once you release it the controller needs to see the electrical signal from the thermocouple to keep the gas valve open.

The thermocouple in the Whirlpool hot water heater is unique in that (a) it has left-hand threads (lefty tighty) and (b) it has a fusible link inside a bulb in the copper sheath. If the material in the fusible link gets hot enough it melts, interrupting the electrical signal and shutting off the gas. This is a one-time event since once the fuse melts it's not repairable or resettable.

The reason for the left hand (odd-ball) threads on this thermocouple is the engineers who designed this water heater didn't want you to install a generic thermocouple - since they don't have the fusible link.

The new improved thermocouple doesn't have the fusible link - it has a typical thermal overload switch (resettable) mounted in the burner door and it has an adapter so you can use a generic right handed thread thermocouple.

Hot water heaters built since 2003 are sealed around the bottom where the combustion chamber is except for an air vent/flame arrester under the heater that lets air in but keeps flames from jumping out if you happen to spill gasoline near the gas hot water heater. The term for this feature is - flammable vapor ignition resistant or  FVIR. Suffice it to say with lots of safety features it's pretty hard to start something on fire with your gas hot water heaters nowadays.

I'm glad I like to learn how things work and fix things that are broken, but I'd like to take a hot shower without having to drive to the gym - so I'm hoping the parts show up tomorrow and the hot water heater  is working by tomorrow night.


The kit "A" showed up about 3 pm Tuesday and I had it installed an hour or so later. Taking the old burner off, installing a new burner jet, reusing the old piezo-electric starter, connecting the new pilot light pipe to gas controller, new main gas pipe to gas controller, thermo-couple adapter and it's wiring was all sort of interesting. I'd rate this job about a 2 on a difficulty scale of 1-5. It's probably about a 3 on a potential danger scale of 1-5 given the danger associated with natural gas leaks/fire/explosions.

The mercaptan (a thiol) added to natural gas makes it pretty easy to detect a leak with your nose - so if you smell that stinky rotten egg smell don't try to light the pilot light, shut off the gas supply, and find the leak. Natural gas is odorless without the mercaptan, but as a result of the New London School Explosion in Texas in the 1930's it was mandated by the Texas legislature and it's use spread around the world. The human nose is extremely sensitive to some thiols - for example the smell of a skunk can be detected at 10 parts per billion. I love Wikipedia...

 If you read the directions carefully, take your time and have some experience with tools, electricity, gas, pipes and stuff it's not a big deal. If that's not your thing I'd call a repair person.

One thing I like about working with your hands and head is the immediate unambiguous feedback that lets you know if you did a good job. The desired end result of this task is easy to define and measure - (a) don't burn down the house (b) don't  blow something or someone up and (c) have hot water.

No arguing, debating, speculating, guessing, just the facts - it either works or it doesn't. If only everything was so clear cut.