Buderus GB142 & AM10

DaBears

I have been having some intermittent problems with my Buderus GB142-24 which now appear to be permanent. My boiler was not producing heat although the zones were calling for it and the circ pumps were pushing it. The last month or so I would just turn the boiler off then back on and it would fire. The last few days the problem was occurring almost daily as opposed to weekly and now I can’t get it to fire at all (DHW still works off the boiler). 

I dug into the user manual and followed the trouble shooting guides. It appears the AM10, the outdoor temp reset module is the problem. If I jump out the WA input on the external connection control the boiler works as it should (that was in the steps to determine the issue) but I don’t want to leave it like that. 

I also noticed that the AM10 at one point was an optional feature.  So I decided to try eliminating it from the equation. I landed the outdoor temp sensor and the stat on/off from the circ pump controller on the external connection control (there was spots for them) I then disconnected the factory connection to the AM 10 and the boiler appears to be working as it should.  

My question is.. is this safe?  Do I need the outdoor temp reset module? The boiler was installed in 2010 and hadn’t been properly maintained. From what I am reading the unit makes the boiler more efficient but can I get by without it as I’m sure I’ll be replacing the entire boiler in another year or so. 

Any help would be greatly appreciated. 

GW

It’s fine, Ditch the AM10. Good job looping around it, most folks give up or don’t try. 

Depending on what heating system you have, you may or may not want a new AM10 

Big Ed_4

Maybe just the outdoor sensor went bad ? What was the outdoor temperature reading on the AM 10 before disconnecting ? I have replaced a few sensors and can't remember replacing the control ....

DaBears

The outside air sensor was showing the correct temp. It was 37 degrees last night and that was what it read.  

DaBears

GW said:

It’s fine, Ditch the AM10. Good job looping around it, most folks give up or don’t try. 

Depending on what heating system you have, you may or may not want a new AM10 

I have baseboard and one small section of in the slab radiant radiant. Bosch tech support got back to me and said even though the external connection has a terminal for outside temp it’s useless and was used in conjunction with a RC35 control. He also said the AUT function on the temp dial is used in conjunction with the AM10. Mine was always turned to a specific temperature and not the AUT so maybe I was never utilizing the AM10 correctly 🤷🏼‍♂️

GW

Right on, I’m guessing you have some sort of mixing valve for the radiant. Not to go to overheat the floor 

aut- yes, there might of been a misunderstanding between you and the Buderus person. I believe that tile is just a maximum, so I believe it would’ve worked normally. 

BoschGuy

Correct! When the boiler first launched back in the day, the AM10 wasn't available, it came later.

So long as XX from the pump relay for the system is connected to the WA terminal on the boiler it is completely safe. That is how we connecting them when the AM-10 didn’t exist.

The other thing I would replace it the thermistor in the outside sensor.

Aluvaboy

The boiler was installed in 2010 and is already being replaced! Oh my God! You should be wallowing in money! My Crown boiler is 22 years old and I am not thinking of replacing it for another ten!

GB142

I have been running an AM10 with my GB142/45 since 2006 and love it. I have been tracking my outdoor temps and boiler temps for years to come up with the best design temp setting. I live in Minnesota so I will set the target point when the outdoor temp is at 14, between 125-135F for best results, as long as my thermistor is working correctly.

In the past few weeks, evening temps have not been as bad as winter, but still in the 18-37F degrees. However, I have noticed a similar problem as DaDears. I thought it may have been where I have target outdoor temp when at 68F was set, so I fiddled with it and set it at 110F hoping to raise the temps, but not much luck.

Any thoughts? Do they still make the AM10, because I am not seeing it anywhere for sale online.

pedmec

i fear that your lack of maintenance is going to be an issue. the condensate produced by the 142 will cause the sheering of the aluminum heat exchanger and when not maintained every year it sits on the heat exchanger and it will get hard as concrete. you should inspect your heat exchanger now that the winter is over.

HVAC_tech

I have 2 brand new Burderus AM 10 Module if anyone need them! 

GrahamT

Where are you located?

GrahamT

(HVAC_tech)