Welcome! Here are the website rules, as well as some tips for using this forum.
If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Repeat 4a codes and replaced sensors a few times and check wiring etc. Could it be plugged on the flow thru the exchanger? circ. working, boiler installed 2006, is this end of its life? trying to get a hold of a local rep. in mass. and budeus tech support seems to be reading a script..