Since October 2010 I am monitoring my Remeha Calenta. With the use of a special cable  and by "reverse-engineering " the protocol with which the Recom software  communicates with my boiler, I was able to get loads of information out of the Calenta. This has some great advantages, like not having to mount temperature sensors to the pipes (which is always inaccurate), being able to easily monitor the amount of usage for DHW (Domestic Hot Water), keeping an eye on the water pressure and being notified of low pressure before the boiler stops working, or a change in the number of failed burner starts or flame losses. And the greatest part is, my Domotica system takes care of all this! Whenever the burner failes to start, I'll have an SMS or email instantly.
Below you can view a subset (the total number of device values is > 100..) of all the information that is provided: Current status, Counter values and I created charts of some interesting device values like Temperatures, DHW flow and more.