New Design help for Hydro Air and other components

Mplsavant

Hi guys, I could use some professional opinions before I have the Pro's come in and give me their idea/bids. Our system is 7 years old and consists of:

- Buderus GB142

- Air Handler zone

- DWH arm tank

- Wirsbo zone in basement slab

- Wirsbo zone in garage slab



For the most part the system has been great, the boiler seems overworked and I've kept up with annual cleanings, replaced the normal stuff (condensate trap, burner gasket, ignitor, etc). There is a current problem with the unit where it will not reach over 150 degrees....we've checked the delta T and that is not the problem. I do not have the AM10 outdoor reset since it was installed in 05' (I bought one, have not had it installed yet). There are no mixing valves on the heating zones, they have their on stat and valve opening but could be running a ton of colder garage water thru the air handler for example if they call for heat at the same time.



My question is I would like to offload the boiler with either a gas water heater or perhaps even a used boiler for the Arm tank and two wirsbo zones.....or any ideas you guys have. Thoughts and thanks in advance. Included a quick pic, will post more if needed.