⟐ Commented February 19, 2026 at 1:22 MST

⟐ Commented January 30, 2026 at 5:58 MST

I checked some answers here and went through some checks.

We get power to both screws on both upper & lower elements.

I checked both elements for resistance and got readings of 19.6 on both.

I checked the resistance of the upper element, screws to heater body and no indication of resistance.

I have replaced the upper thermostat.

What else could be the problem?

Thank you,

Dave

⟐ Commented December 26, 2025 at 7:34 MST

Both elements are both 11.5 ohms and appear to be good. Am attempting to remove and measure the thermocouple but using the digital diagnostic, I observe lower on at 54 F and upper at 77F, so are somewhat reasonable values for a tank that was at room temperature and then had some water come in from the well into the lower chamber.

I understand that these controls me only turn on one heater element at a time which would explain the upper element getting voltage for 30 seconds or a minute but then unclear why the control with turn off the heat without posting any kind of error code as there are no codes in the history.

Any help would be appreciated.

Called Richmond (Rheam) customer service.The representative felt this was likely a faulty digital circuit board since no error codes were being posted in the history and due to the behavior observed where the upper element was powered for about a minute after a power cycling off/on using the circuit breaker. Service person advised me that the upper heater element would normally be powered for about 20 minutes before switching power to the lower heater element.

New circuit board being sent free of charge under the 12 year parts warranty.

⟐ Commented December 14, 2025 at 10:35 MST

⟐ Answer edited September 25, 2025 at 23:56 MST

Chris Stillman

***1 minute ago

UPDATE: The leak is coming from the bottom device. I'm looking into this manual if that pulls out, etc. Any input is welcome.

***

Hello, I woke up to a nice puddle of water underneath the water heater. It is spraying water out from the inside. The water is literally spraying out from behind the section in the photo attached.

I may be in over my head on this one but figured I'd check in with you guys!

Thank you!

⟐ Commented June 07, 2025 at 19:30 MST

My geyser not boiling

⟐ Edited April 25, 2025 at 1:39 MST

The top element is shot. Power but no heat.

Can I rewire it so that when the upper thermostat tries to power the upper element, it goes instead to the lower thermostat?

Clearly the upper thermostat is going to be too cold to turn off for a long time. Until then, it would provide power to the lower thermostat which should also turn on the lower element until there's enough hot water in the bottom of the tank.

Relying on convection to mix the upper and lower parts of the tank, I would expect to get at least lukewarm water with the bottom thermostat cycling on and off pretty regularly. If it ever gets to the desired temp, either the top or bottom thermostat will kill power to the lower element.

Based on the B-W installation manual, I would accomplish this by

(1) Disconnecting the upper element from the upper thermostat by removing the yellow wire from T2.

(2) Move the black wire on T4 (lower thermostat power) from T4 to T2.

See page 7 of the manual ta https://www.manualslib.com/manual/20112/...

This will cause the lower thermostat to be powered anytime the temperature on the upper thermostat would call for heat.

Only has to last a week or so.

Thanks!

⟐ Edited by author January 12, 2025 at 18:49 MST

Have reset and got flashing P01 but nothing happens. Was working night before last. It was very cold overnight and last night wouldn't come on. Have tried to investigate this evening but all guidance says to reset and when P01 appears, system should fire up.

Nothing happening, house freezing, no other source of heating.

😢🥶

⟐ Answered November 23, 2024 at 9:23 MST

⟐ Commented November 21, 2024 at 10:51 MST

The issue is, the fan isn’t getting power from the PCB so is the PCB at fault or is there something else I can check? Can anyone help?

⟐ Answer accepted October 31, 2024 at 9:46 MST

⟐ Commented September 21, 2024 at 10:33 MST

⟐ Commented September 08, 2024 at 19:16 MST

⟐ Commented August 17, 2024 at 1:28 MST

The control unit was basically not displaying any of the values for the three thermistors connected to it, it is as if it wasn't looking at the sensors and the codes that were entered by the heating engineer initialised the controller to look at the sensors and display the values on the display. Without a valid temperature for the boiler it wouldn't do jack. Is there not a Viessmann engineer out there with access to the engineering manual that could look up the initialisation procedure for me?

⟐ Commented July 06, 2024 at 10:02 MST

⟐ Edited April 11, 2024 at 7:09 MST

⟐ Commented February 16, 2024 at 7:52 MST

⟐ Commented December 16, 2023 at 1:01 MST

⟐ Answered November 02, 2023 at 15:03 MST

⟐ Commented October 09, 2023 at 0:29 MST