In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Burnham ES-25 gas boiler installed 2 yrs. ago w/55 gal.water heater storage tank. 2 zones, outside reset,new ss liner inside clay chim.When outside temps get below 40's I start getting a light sheen of water down the wall. Absolutely not weather related. Neighbor had same system put in same time by same plumbing company on Long Island in NY. Has same exact problem. Burnham customer service absolutely worthless. Ditto National Grid, contractor. Was told I need to keep domestic hot water temp.@130 deg. by the plumber. .This is an outside chim. that was not insulated. Water stain is a littl rusty--seems the Stainless Steel liner that is code----was not exactly the best on the market. Magnet sticks. Anyway, put the flue damper switch in the always open position and problem cleared up. Shouldn't there be another solution besides resorting to this.