Tomorrow I'm installing a Bosch ZBR 35 combi boiler for the first time. I'm just reading through the manual and Its says that that Internal Expansion vessel pre-charge pressure must equal the static system height of the boiler.
How exactly do I calculate whether or not I would need to add an on another expansion tank? I believe I need to find out how many gallons the system holds. Now this being a retrofit that might be tricky. Can anyone point me in the right direction here?
a simple system w/ a copper finn tube set up you are prob going to be fine. I might leave a threaded tee on the return to make a way in case you need it.
You can add a bit of air to the extrol inside if you have abnormal height.
This post was edited by an admin on July 23, 2013 11:16 PM.