CEC Model 45-551301 Electric Tankless Water Heater

[LarryB]

I have a CEC Model 45-551301 electric tankless water heater that stopped working 2 days ago. Unit is likely circa 2004-2005 since Bosch bought CEC in 2005. No light coming on anymore on front of unit when hot water turned on. Breakers were not tripped. I shut off breakers and opened unit to take a look. Found the circuit board burnt up pretty bad. (I heard crackling noise the other day and looking near the water heater, but found nothing so I didn't realize what had happened.) I have a plumber coming this week to replace unit. My question is, what is likely to have caused this to burn up after ~20 years? Could it have been a power surge? Or just circuit board failure due to age if unit? And why wouldn't the circuit breakers trip? Located in central florida also, in case that helps/ On well water.
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[Fitter30]

Has the heater every been flushed? Has is been cleaned with vinegar and a pump? Have a water softener? How long do you think a heater should last?

 

[Sponsor]

 

[LarryB]

I don't believe its been flushed. No water softener. I didn't expect it to last this long. My question was concerning what may have caused the circuit board to burn up, so I know if I need to look further than replacing the unit itself, so it doesn't happen again.

 

[Fitter30]

I don't believe its been flushed. No water softener. I didn't expect it to last this long. My question was concerning what may have caused the circuit board to burn up, so I know if I need to look further than replacing the unit itself, so it doesn't happen again.

Left side 4th wire down that is where it started with the board at the white spot burned up. Wires blacken from the smoke. That element probably went to ground or shorted out pulled more amps instantaneous that the ribbon could take and vaporize.

 

[LarryB]

Thank you Fitter30

 

[WorthFlorida]

A thousand reasons why the board burned up. As with all electronics there is a limited number of power cycles and each one takes a bit of life out of it. Power surges or nearby lightning hit takes its toll. the way the wires are blacken, the heating elements may have been drawing too much current for a while.

It does happen, the main circuit breakers can fail. Years of high current draw, internally the contacts can weld together and the breaker will not trip. After manually operating the breaker, the contacts break loose and the breaker will seen to operate normally.

I had this happen at a coworkers home she was selling. After the home inspection the WH breaker would trip every time. I found that the previous owner hack the wiring so both heating elements were on at the same time.

Twenty years you did pretty good.

My suggestion is replace it with a standard 50 gallon WH and replace the breakers

 

[LarryB]

Thank you WorthFlorida. Appreciate your reply