Specifications

12
MyBacharach.com • Fyrite
®
InSIght • Instruction 24-9460
Performing Tests
Domestic hot water heaters with the ‘bell’ shaped draft
diverter on top can be accurately tested by attaching a
section of copper tubing to the probe or using a flexible
probe which is then inserted directly into the top of the
fire tube below the diverter.
Another common practice is to insert the probe in the hole
drilled for the draft test, direct it down and push it below
the level of the draft hood.
Condensing furnaces/boilers can be tested through a
hole drilled in the plastic vent pipe (when allowed by the
manufacturer or ‘local authority of jurisdiction) or taken from
the exhaust termination.
In order to obtain an accurate Steady State Efficiency reading,
an auxiliary thermocouple must be inserted in the combustion
air intake so that a true net stack temperature is used in the
calculation.
It is important to remember that the vent system on these units
operates under a positive pressure. As a result, any holes in
the vent need to be sealed.