In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
A client of mine has visible corrosion of the smokepipe/venting due to sustained flue gas condensation. It's a Buderus G124, 3-zone system (zone 3 being a DHW priority w/ indirect)
After doing the math I've found that when all the baseboards are cooking and the inside temperature is at 70F the coldest the return water will get is 157F. Seems alright there.. BUT
The issue has got to be the fact that gases are vented into an exposed brick, outside chimney. It's currently piped in a branch header style. The only solution I'm seeing is to re-pipe as a primary/secondary to keep the return water as hot as possible.
Does anyone have any suggestions on how to combat this? Or, perhaps its another issue I'm not addressing?