Honeywell Thermopile Voltage Low: How we troubleshooted

Update June 2019: For those looking for a solution to this problem, we ended up un-installing our new water heater, hauling the entire tank back to Home Depot, and switching it out. The second one worked just fine.

Although I will say- I sure do get a lot of views from this article, which leads me to believe that Honeywell knows about this issue, but they are for sure not letting on about it.

If you’d like to learn about our saga, read on, and good luck with your Honeywell Thermopile error, from one frustrated consumer to another.

So as it turns out, our hot water heater drama didn’t end with the installation of the water heater tank. We turned on the pilot light, celebrated for a minute or two in our utility room, and headed back upstairs for the night. Yay! Hot water heater replaced! We are getting great at this home DIY thing.

After reviewing our success over a cold one, Sam jumped up and said, “I’m going to go check the pilot light.”

If there is one thing about my Sam, it’s that he loves to look at and review his work.

“The pilot light is off.” He shouted from the basement.

What?! I ran downstairs. Sure enough, that pilot light went out, and Sam had relit it.

We wait for a couple of minutes… and the stupid thing went out again.

We lit it again… and it went out again…

And a fourth time…

WTF!! This time it was giving us a thermopile error. The unit had low power. The thing would blink red two times, and shut down. The official error was “Thermopile Voltage Low”

Honeywell gas water tank thermostat unit

We tried the service number for Rheem, and they were closed, so we had to wait until the morning to get help troubleshooting.

No hot water for another night…

The next day, Sam got a hold of a Rheem service tech. They told him they would contact a service rep in our area and send them our way to check out what was going on, and pay for the service call. Great! They would be calling us back within the next 24 hours.

He’d also called Home Depot, and asked about a return. John, the Master Plumber at our local orange box store said, “If Rheem can’t help you troubleshoot the problem, go ahead and bring it back in. It won’t be a problem.”

No call back for the rest of the day.

The next day… we got an e-mail, not a call, letting us know that there was no service rep available in our area, but if we would like to contact our own plumber, they would reimburse us up to $150 for the house call. The email included lots of stipulations and hoops to jump through in order to work with this plan.

No thanks!

I began thinking to myself, screw Honeywell, and screw Rheem, and screw Home Depot for selling such a crappy product. We are returning this unit, and going to Lowe’s. Ha! That’ll show them!

I researched the crap out of this issue online, and found out that there were a ton of people having this same problem. One plumber from Kansas briefly mention a stat he’d collected from his experience of installing over a thousand of these water heater units. About 1 in 125 units will have this Thermopile Voltage Low error. Ok, so that’s less than 1%. That must be an acceptable quality threshold for Honeywell.

So then I hopped on the Lowe’s website, and searched for gas water heaters. And would you look at that….. THEY ALL HAD THE SAME HONEYWELL THERMOPILE UNIT! Talk about a hold on the market. Well done Honeywell, well done.

Backed with this info, we had a decision to make.

  1. Return the tank and trade it out for another one.
  2. Call a plumber to fix our problem.
  3. Replace the Thermopile ourselves.
  4. Return the tank.

We didn’t want to replace the Thermopile. That would take days to receive a replacement…. and we didn’t want to deal with getting a hold of a plumber, scheduling an appointment, paying the full service fee (plus who knows what else for repairs), and dealing with Rheem for reimbursement. Mmmm, no.

So we decided to drain that stupid tank, and return the damned thing.

We got that sucker out in a couple of minutes, loaded it up in Big Bad (Sam’s Truck) and took her on back to the big orange store. Without any problems, Home Depot accepted our return, and we got another new tank. Same model, just switched it out.

We brought our new baby home, and installed a water heater tank for the second time. Really? Another two-for-one? (Read about our bedroom door installation)

This installation took less than 15 minutes. Hey, maybe we ought to get our plumbers license??

With the pilot light lit, we sat in waiting. And waited…. and waited some more for the light to go out.

And would you look at that? It didn’t!!! We turned up the heat to low, and let it temper for a while. After adjusting it a few times, we turned it up to the setting just before the A position. (The settings go from Low-High-A-B-C-You’ll definitely die if you set it here)

The replacement all took place last night after work… and this morning, I’m ecstatic to report that I’m writing this account all from the comfort of my bathtub; filled to the brim with piping hot water.

TMI? Haha.

With Love, Erika Nora


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