Buderus aluminum boiler pH

Saybrooke

I have an aluminum boiler and the pH is at around 10. Will this cause a problem and if so how long will the boiler last if the pH is at 10.

PerryHolzman

Your pH is basic - thus the water in the system should not corrode the aluminum from inside.

However, combustion gas acid corrosion and galvanic corrosion between the aluminum and whatever its connected to on the water side, if not done with galvanic isolation connections, are the most likely failure modes. It's not really possible to predict a timetable on that.

The 1st generation aluminum boilers did not do well and had short lives for those reasons. I cannot say if they have adequately beefed up (made thicker so it has a long fireside corrosion life) and used proper galvanic isolation on the newer models for appropriate life. That's likely a mfr & model specific question.

I wish you the best with your boiler - and hope it lasts a long time.

Perry

hot_rod

Just plain water? or does it have hydronic conditioners or glycol in it? Any fluid added that was designed for hydronics tends to raise ph. I think you want to be 8- 8.5 for that boiler. What does the manufacturer suggest?
I think it is good to have some aluminum friendly conditioners in aluminum boilers. Some info from Rhomar here. A long read, worth the time.