LoNox Circuit Board Tab Question

[Palmero]

Hello.

Rheem Heater model: P-M267AENC
Serial Number: 0701192652
Natural Gas Fired

I just received a new control board to replace the old one that is faulty. I made all connections and was getting a LoNox error. After I disconnected a white with purple stripe cable from the connector labeled LoNox, the heater fired right up.

According to the instructions, there is a tab that must be broken off, but I'm hesitant to do so and ruin the new board.

So, to summarize, with the tab in place and the white/purple cable disconnected, the heater works fine. But, if I connect the cable, I get the error. Reading up, there are some heater models where the tab must be left in place, but I'm not sure if my model (267?) requires the tab to be broken off.

My question is, should I leave the tab in place without the cable connection, or break off the tab and connect the cable?
What is the purpose of this cable and what is meant by LoNox?

Here is a photo of the original old board that came with the heater. The tab was
broken off:



New board, front and back with tab intact:



Much appreciated.

 

[1poolman1]

Hello.

Rheem Heater model: P-M267AENC
Serial Number: 0701192652
Natural Gas Fired

I just received a new control board to replace the old one that is faulty. I made all connections and was getting a LoNox error. After I disconnected a white with purple stripe cable from the connector labeled LoNox, the heater fired right up.

According to the instructions, there is a tab that must be broken off, but I'm hesitant to do so and ruin the new board.

So, to summarize, with the tab in place and the white/purple cable disconnected, the heater works fine. But, if I connect the cable, I get the error. Reading up, there are some heater models where the tab must be left in place, but I'm not sure if my model (267?) requires the tab to be broken off.

My question is, should I leave the tab in place without the cable connection, or break off the tab and connect the cable?
What is the purpose of this cable and what is meant by LoNox?

Here is a photo of the original old board that came with the heater. The tab was
broken off:

View attachment 609678

New board, front and back with tab intact:

View attachment 609679 View attachment 609682

Much appreciated.

For that board to work with a LoNox heater, as yours is, the tab has to be broken off.
LoNox = low nitrous oxide emitting. Basically a smog controlled heater. Absolutely required in the SCAQ District and beginning to take effect in the entire State.
Why was a new board ordered?

 

[Palmero]

Hi.

Appreciate the explanation. I reached out to Raypak and it is indeed a LowNox heater. Once I confirmed, I removed the tab and is now working fine.

As to why a new board was ordered, the heater started showing a code of CLK intermittently, sometimes it would fire for a few minutes and then go to CLK again. Tapping the front of the display would "fix" it for some time, but then go back to CLK. After some research, I learned this code is related to a "fireman" connection, which as I understand it, allows the timer to turn off the heater a few minutes before the pump goes off in order to cool it down. However, I do not have this feature on my timer.

I took out the board and visually checked it. I noticed that thee connection where the temperature sensor cable goes (green, black, green) wire was very loose where it soldered into the board. I may have caused this while disconnecting the wires to inspect it. After that, the code changed to SNS.

Some suggested soldering the connectors back in place, but I'm not that good soldering those small connections, so I decided to just get a new board. I found some used boards that were cheaper but didn't want to take the chance.

It was expensive, but the heater is in good condition and that fixed the problem.

Thank you very much for you help.