Isata 5 Truma water heater outside power light not turning on

[Niagr8ce]

Hi! I’ve searched the threads on the Truma water heater but cannot find any fixes for our problem. The water heater light at the power panel on/off Switch will not turn on (doesn’t light green) and will not start the system. We’ve tried recycling power and completely turning off power at the battery barrel switch in hopes that the system would reset. It did not. We also tried turning off/on the propane, master light switches, and pulled and reseated the fuses with no luck as well. The Precision Plex panel says the fuses are good and we visually checked them- they are. Any ideas on how to get the Truma to turn on? Or reset?

[NearDenver]

Did you check the power switch on the unit? Need to remove the outside panel.

[Niagr8ce]

We did. That’s the light that is not turning on. Normally we turn the power switch on on the green indicator light comes on. But now we are not even getting that to work or the inside knob to light up when cycled to the on position

[milkman55]

These rotary switches have a history of being finicky. First off, check what was suggested above and remove the cover outside and make sure the power switch on the unit itself is turned up or down (doesn’t matter).

Then SLOWLY turn the rotary switch up to the Eco mode and watch for the green light.

If you can’t get the green light to come on, you can bypass the rotary switch completely by removing the black telephone looking plug in the upper right hand corner of the water heater outside behind the cover. I already had Truma send me a new rotary switch for my 2021 Isata 5.

[Niagr8ce]

Thanks! No green light but if we removed the black plug- is the green light supposed to come on ?

[milkman55]

I think we are talking about two different green lights. There is a green light inside the rotary dial and then the two green lights on the Truma unit itself. Try flipping the on/off switch up and down and see if either position gives you a green LED on the Truma itself.

[milkman55]

The data cable to unplug to disable the rotary dial is circled in the picture.

[Niagr8ce]

Still no luck. We have tried both on positions on the outside panel (no lights) and rotating the inside dial the cycle power between eco and heat mode (no lights). Then we also tried removing the black plug and putting the unit in the on position with rotating the dial several times but still no joy. Open to anything else you may have

[milkman55]

You didn’t mention what model Dynamax you have, but since you mentioned the red rotary dial, I am assuming Isata 5?

Inside the door there is a “Master Lights” that cuts all the 12v power. Make sure that is not turned on. If it is you should not have any 12V lights or anything else 12V. It also cuts the power to the Truma.

Once you unplugged the black data cable, that disabled the rotary dial and it’s no longer in the equation. Once the data cable is unplugged, only the up and down positions on the Truma itself have any impact. Check your “Master Lights” and make sure you can turn on other 12V lights.

[Niagr8ce]

Sorry. We have an Isata 5 36DS. The master light switch is “off” meaning I can turn on other lights and stuff with 12V. I have tried turning in on the power everything off and turning it back off in hopes of resetting the system. No luck either. Is there another 12v reset to try? We have even tried cutting power off completely at the battery barrel and turning it back on but no response from the truma unit

[milkman55]

On Monday call Truma directly. They are very responsive.

Truma - George x 303
*(855) 558-7862‬

[bclemens]

Originally Posted by Niagr8ce

Sorry. We have an Isata 5 36DS. The master light switch is “off” meaning I can turn on other lights and stuff with 12V. I have tried turning in on the power everything off and turning it back off in hopes of resetting the system. No luck either. Is there another 12v reset to try? We have even tried cutting power off completely at the battery barrel and turning it back on but no response from the truma unit

Depending on what year your Isata 5 is....we were adding that to the precision plex system.

It is on the main panel called "LP Heater" in the shape of a water droplet. Make sure that is on. Then just leave it on...turn the Truma off and on from the other sources.

[Tom in Ohio]

Originally Posted by milkman55

You didn’t mention what model Dynamax you have, but since you mentioned the red rotary dial, I am assuming Isata 5?

Inside the door there is a “Master Lights” that cuts all the 12v power. Make sure that is not turned on. If it is you should not have any 12V lights or anything else 12V. It also cuts the power to the Truma.

Once you unplugged the black data cable, that disabled the rotary dial and it’s no longer in the equation. Once the data cable is unplugged, only the up and down positions on the Truma itself have any impact. Check your “Master Lights” and make sure you can turn on other 12V lights.

MY Master Light switch has No effect on or off on the Truma....or any other circuit other than lighting????

[bclemens]

Originally Posted by milkman55

I think we are talking about two different green lights. There is a green light inside the rotary dial and then the two green lights on the Truma unit itself. Try flipping the on/off switch up and down and see if either position gives you a green LED on the Truma itself.

The light on the dial is actually amber.

[bclemens]

Originally Posted by Tom in Ohio

MY Master Light switch has No effect on or off on the Truma....or any other circuit other than lighting????

Very well could be...it was only a brief period when this happened.

[Niagr8ce]

We have a 2020 model Isata 5 36DS. The only icons on the precision Plex monitor are for the water and entry stairs. On the fuse panel there are two fuses that are labeled water heater and both read “ok”. We also visually verified that the fuses are good.

[bclemens]

OK, 2020 means a few things.
1. It will not have an on-off in the multiplex panel
2. I don't recall which units were added to the "master light switch" but I think they were older ones. So to be safe, make sure master switch is ON (ie all lights are on).

3. Go outside and open the water heater door. turn it off at the water heater

4. Unplug the data cable that goes to the interior rotary switch. That is the one circled in purple on post #7.

5. Then turn the water heater ON. Up for Eco and down for Comfort. Green light should come on.

[bclemens]

Then I just went back and read everything and it was working and now it is not.

So try the above and if that does not work, then it is likely a fuse. Even if they look good, I would test them to be safe. We have had posts here about fuses that "looked" good, but were not once they were tested.

[milkman55]

Just replace the fuse as a test. I bought this box of fuses off Amazon and it has all the sizes used by both Dynamax and RAM. Always carry extra fuses.

https://www.amazon.com/gp/aw/d/B01DY...b_b_asin_title

[Niagr8ce]

Appreciate the help. We replaced the fuses and removed the data cable and followed the above steps but still no green light on the truma unit. We will give truma a call in the morning and hopefully they can help . Thank you