# exploding on demand water heater



## robertmilo1 (Aug 25, 2015)

So i was fixing a eemax point of use water heater today in a comercial building. Figured it was just a inlet filter problem (low flow out of the faucet, unit not kicking on) at least that has been the issue on a number of these things that I've fixed. I killed the power, shut off the water checked the inlet filter, sure enough it was clogged, cleaned it, started putting it back together, got the water hooked up, was screwing the "motherboard" panel back on (i didn't have to take it off, but discovers that later, anyways it was just two screws, didn't mess with wires or anything) as soon as i started screen that back on, and remember the power to it is shut off at the breaker, it started making a clicking and static sound (water has not been turned back on yet either) within 10 seconds BOOM! It exploded. Like a bomb, i got minor cuts from the shrapnel, was dazed and went deaf with a hard ringing in my ears, which faded, so no real injury done. But why!?!?! It makes no sense to me. I called the manufacturer and they just said that it is 21 yrs old, discontinued and should have been replaced a long time ago. So no help from them. Anyone have an idea?


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## younger-plumber (Sep 12, 2008)

You forgot to unplug the thermocouple from the flow activator disengagement switch solenoid. Rookie mistake.


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## Redwood (Sep 8, 2008)

younger-plumber said:


> You forgot to unplug the thermocouple from the flow activator disengagement switch solenoid. Rookie mistake.


Yep That'll do it every time...:thumbup:

Robert, Id suggest that you make an Intro Post...
It will greatly enhance the pleasure of using this forum if you are a plumbing pro.:yes:

It will also keep you from getting hit with more shrapnel...


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## plumbdrum (Nov 30, 2013)

I was thinking it was the flux compositor


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## Redwood (Sep 8, 2008)

You misspelled it...



plumbdrum said:


> I was thinking it was the flux *composter*


There I fixed it for you...


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## plumbdrum (Nov 30, 2013)

Redwood said:


> You misspelled it... There I fixed it for you...


Freakin spell check on my iPad and typing fast is a bad combination.


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## plumbob2008 (Jul 29, 2015)

Few years back had a sets whole house electric instant water heater do same thing no relief valve blew cpvc water line was in closet next to master bedroom sounded like a bomb owner want new tank water heater was scared of them


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## robertmilo1 (Aug 25, 2015)

You forgot to unplug the thermocouple from the flow activator disengagement switch solenoid. Rookie mistake.

Ok thanks, i dont know why t hi had never happened before? I have done the same thing to other similar water heaters. I figured killing power at the breaker would be sufficient, and when this happened the power was still off, and water was still off.


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## Redwood (Sep 8, 2008)

The Flux Composter holds stored energy which must be bled down using a resistor and jumper leads...

Seriously you need to do that Intro...


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## Gargalaxy (Aug 14, 2013)

Redwood said:


> Seriously you need to do that Intro...


This is his intro :whistling2:


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## Redwood (Sep 8, 2008)

Gargalaxy said:


> This is his intro :whistling2:


Lucky he didn't level the house...

And kill someone...


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## jc-htownplumber (Feb 29, 2012)

We are visual people. We expect pictures


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## BOBBYTUCSON (Feb 8, 2013)

Can all on demand or pou heaters do this ?


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## Redwood (Sep 8, 2008)

BOBBYTUCSON said:


> Can all on demand or pou heaters do this ?


When a GC starts messing with them... Sure!


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## BOBBYTUCSON (Feb 8, 2013)

Redwood said:


> When a GC starts messing with them... Sure!


Lol ok ill take that


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