Performed preventative maintenance for a Peerless cast iron boiler. Water pressure is at 18 psi. The hot water limit is set for 180. Performed a combustion analysis test and got the following readings, o2 is at 15.9%, co is at 0 ppm and the system is running at 83.3% efficiency. We did find the main house zone seems to be stuck open. The other zone serves a small section of the house. See estimates for details on repair for this zone. Otherwise the system is functional at this time.