Buderus GB142 temperature adjustment

rich p_4

Good Morning,
I have a customer with a (15yr old) GB142 and an indirect with a plate exchanger.
It is wired like a heating zone, so its not using a sensor. Two circulators running during a call for hot water. Simple on/off type thing.
Is there a simple adjustment to increase the boiler water temperature.
The boiler will only get up to 120 degrees F. This will not give satisfactory hot water
and it has not for years. I was able to get the boiler to fire and get to 170
However I was not able to save that adjustment. I remember it was adjusting the load as it read in the manual. I trip over this boiler only on occasion.
Thanks,
Rich

Ironman

I’m not sure what you mean by “an indirect with a plate heat exchanger”. I’ve never seen a setup like that.

However, the GB142 was designed to use a separate pump and piping connected to the boiler manifold from the indirect. That pump should be connected to the “PS” terminals on the boiler.  A tank sensor was provided with the boiler and should be connected to the “FW” terminals on the boiler. This is how it’s designed for an indirect.

Connecting an aquastat to the “WA” terminals will bypass the ODR function of the AM10 control and send the SWT to 194*, but it won’t give domestic priority or energize the “PS” pump terminals. Unless some means is provided to de-energize the space heating pump during that scenario (like a pump relay), extremely hot water will be sent to the space heating zone.