Outside air sensor error with Buderus 2107n

Bobbyd2727

After getting a "OA Sensor Err" on the 2107 readout display, I obtained a new sensor and replaced the old sensor. This worked for four days, as the error display went away and the system read as it normally does. After the four days the error display returned and I took the wire apart at the sensor and retired it . This time it worked for a few hours and then the error was displayed again. Anyone have a suggestion as to what should be done next? Thanks!

Bobbyd2727

I meant the R2107. No n

Ironman

Replace the cable or, if it has extra wires that are unused, try connecting them on both ends. Make sure all connections are good.

Bobbyd2727

By replace the cable ,you mean replace the wire between the R2107 and the sensor right? Thanks

Solid_Fuel_Man

Wire up the sensor directly to the control to and leave it for a few days. Defeat the outdoor reset so you still get heat and it doesn't go into WWSD.

Bobbyd2727

Sorry I don't understand that last comment. The boiler is working fine heating the house normally. I believe the R2107 is directly connected to the outdoor sensor from one of the low voltage connectors. I read that when the sensor is in error the boiler works by assuming it is 14 degrees F outside. I am considering taking the old wires off and reconnecting new wire 18-2 awg from the R2107 to the sensor.

Bobbyd2727

came home from work tonight and its working again. does anyone know why this is intermitently working and then not working?? bad wire??

Solid_Fuel_Man

It's most likely an intermittent connection in the wire to the sensor. That's what I was referring to by "eliminate the wire" by wireing directly to the control.

Bobbyd2727

i'm sorry I don't understand. How do you eliminate the wire if the outside sensor has to be wired to the low voltage connection at the R2107 control?

GW

Usually there is some slack so just cut a 6" or 12" or whatever piece of the existing wire and tie the outdoor sensor directly to the 2107. The cover of the 2107 is simple to remove. Don't touch the larger wires or terminals, that's 120 voltage

The terminals you are looking for are FA (I'm going off memory but here) , small wires. Now of course the boiler thinks it's 50 or 60 degrees outdoors because your sensor is now in the basement.

You may need to put your system in manual and turn the dial down to 140, just be careful as the water heater may be much hotter (140 degrees), you don't want anyone getting burned

It's possible a mouse chewed the wire, or a staple was driven a bit too tight , doesn't really matter what the problem is, you just need to correct it

Make better sense? If the error message goes away then you need to replace the entire wire line, normally not a big deal.

If you're not comfortable with wires then call a heating guy that knows buderus, or an electrician

Bobbyd2727

Thank you very much ,understand now and will try it.