here you go
I. The inspector shall inspect:
the heating system, using normal operating controls.
II. The inspector shall describe:
the location of the thermostat for the heating system;
the energy source; and
the heating method.
III. The inspector shall report as in need of correction:
any heating system that did not operate; and
if the heating system was deemed inaccessible.
IV. The inspector is not required to:
inspect or evaluate the interior of flues or chimneys, fire chambers, heat exchangers, combustion air systems, fresh-air intakes, humidifiers, dehumidifiers, electronic air filters, geothermal systems, or solar heating systems.
inspect fuel tanks or underground or concealed fuel supply systems.
determine the uniformity, temperature, flow, balance, distribution, size, capacity, BTU, or supply adequacy of the heating system.
light or ignite pilot flames.
activate heating, heat pump systems, or other heating systems when ambient temperatures or other circumstances are not conducive to safe operation or may damage the equipment.
override electronic thermostats.
evaluate fuel quality.
verify thermostat calibration, heat anticipation, or automatic setbacks, timers, programs or clocks.
From International Standards of Practice for Performing a General Home Inspection - InterNACHI http://www.nachi.org/sop.htm#ixzz34HN9hgRV