We converted to a natural-gas furnace in the fall of 1992, and Laird (who had been handling our earlier oil burner which was in the house when we bought it in 1986) handled the switchover, too. We have subscribed to their basic Annual Furnace Maintenance Plan ever since. The annual cleaning and inspection includes checking carbon monoxide levels in the combustion chamber.
On our last annual cleaning, the Laird guy said the CO was too high, probably due to corrosion on the cast-iron heat-exchanger plates. My wife has a friend who is a combustion engineer, and he came by and said it looked like the original furnace installation in 1992 had neglected to install a "shunt valve" between the hot-water and cold-water lines such that the water going into the boiler would be at the designated (as per the furnace installation manual, which I still had) temperature of between 120 and 140 degrees F. The fact that the water going into the boiler at first start-up each heating season was too cool (about 100 deg F) was the cause of the heat-exchanger corrosion.
When I pointed this out to Laird & Son, they very honorably agreed to send a technician by to clean the heat-exchanger plates for free (usually about a $400 charge) and next they sent someone to install that needed shunt valve, also for free. So, from here on out, the rate of corrosion on the heat exchanger plates (which produces the carbon monoxide) should be significantly slowed.
- Approximate cost of services:
- $0.00