Air-Proving Switch - A.O. Smith COF 199 Installation, User And Service Manual

1.3.4 Air-proving switch

This section is only applicable, if the heater has been
equipped with a gas-fired burner.
The air-proving switch monitors the air flow to the burner
during the pre-purge cycle and operating cycle of the
water heater. If the air flow drops below a threshold
value, the air-proving switch will measure an insufficient
difference in pressure and will cut out. This causes the
gas supply to the burner to be shut off immediately.
The switching point of the air-proving switch of Riello
front-mounted burners is:
UNIT
COF 199
COF 245
COF 315
COF 385
COF 455
COF 700
The values above are recommended settings and have
been determined under laboratory conditions.
The air-proving switch's switching point must be set
during the commissioning of the water heater. Please
make sure that the air-proving switch cuts out before the
CO contents of the flue gas reaches 2000 ppm.
This is checked by slowly closing the air supply and
verifying that the burner controller locks before the CO
contents of the flue gas reaches 2000 ppm.
Pressure difference for switching off [mbar]
GAS G20 GAS G25
3,4 3,3
5 5
4,1 3,9
5,5 5,5
5,8 5,9
6,2 6,2
GAS G30 GAS G31
3,4 3,2
5 5,3
3,6 4,1
5 5
5,7 5,9
6,3 6,5
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