The images and readings I performed were on chimney linings. Specifically the effect of combustion gas temperature on the chimney lining. When fuels such as propane (C3H8) and natural gas (CH4) are combusted, nitric acid (HNO3) is created. If the flue gas temperature drops below the dewpoint in the chimney, this acid will precipitate and deposit on the interior walls of the chimney and at the lowest level. Nitric acid from this process has a pH between 1 and 3, which is very acidic. When the products of combustion from the fuel burning device are discharged at a high enough temperature, condensation is not a concern as far as the chimney goes. However, as boilers and furnaces become more efficient by capturing as much heat as possible from the flue gas, the odds of condensation in the chimney increase. Nitric acid will quickly destroy carbon steel, cause deterioration of brick and mortar, and can have a long term effect on clay tile.
“my essay” In Florida a majority of hvac systems are split systems. A split system uses a central ac and a heat pump. At first did not know the difference in weather or not it was a heat pump until a friend of mind showed me a trick. On the outside unit you will find an extra small nipple on the exterior unit, just not reading the thermostat will give you all the clues.
“my Essay” Central AC inspection . Periodically check the outdoor unit or condenser unit. Make sure the unit is free and clear of foliage and accumulated debris. Keeping this unit free of leaves will help the proper air flow of the unit.
While inspecting the forced air natural gas furnace I note the condition as satisfactory. It had a trap installed properly. The gas line shut-off was installed properly as well. The ducts were air tight and it functioned well using normal controls(thermostat).
I inspected a newly installed propane gas furnace and noted that there was not a shut of valve installed. The furnace would not come on by via thermostat when in auto mode, however it would operate correctly under the manual/fan mode. Noted that further evaluation is needed by a qualified HVAC installer/service tech.
During recent home inspection on a single family house, I noticed rust at the bottom of blower compartment of Carrier furnace. Tracing rust from bottom upwards found loose connection on condensate pipeline. Pipe/rubber elbow connection spring clamp was not properly installed. I recommended to address this to qualified HVAC contractor to repair.
According to InterNACHI’s Home Inspection Standards of Practice inspector shall inspect lintels above the fireplace openings, damper doors and cleanout doors and frames. But do not forget very important points of inspection - hearths and hearth extensions. Look for evidence of joint separation, damage or deterioration of the hearth, hearth extension or chambers.
According to the Healthy Homes, Part 12: Heating, Air Conditioning, and Ventilating course, over half of the homes in homes in the USA use natural gas for heating and cooking. The potential accumulation of leaked natural gas and/or the products of incomplete combustion inside a home interior do kill and injure many hundreds and thousands each year, so a carbon monoxide (CO) gas detector well placed and regularly checked for operation is a must for life safety.
The heat exchanger in the forced air furnace was observed with the defective conditions, e.g. a yellow flame which flickers with the circulation fan and rust/corrosion of the exchanger metal surround. The entirety of the heat exchanger is visually inaccessible and beyond our scope of inspection. An unknown level of increased Safety and Financial risk can be assumed without further inspection. A qualified specialist, e.g. licensed Heating (HVAC) Contractor is recommended for prompt further investigation and opinion for service repairs and/or upgrades.
