Crown Boiler PHNTM080, Installation And Operation Instructions Manual

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118
Air Proving Switch (APS)
– This pressure switch is normally open and is connected to the outlet tapping on the gas valve as
shown in Figure 14.5. During pre-purge, when the gas valve is closed, the IAS is monitoring the pressure drop across gas-air
*_) #“Œƒ+Œ\' #Œ&“Œ` '#%## *# & %
to increase. The APS is calibrated to close when this pressure rises to 1.05 +/- 0.05” wc, which is a pressure at pre-purge
& %&( '#%))\# ' &){\%&#
'#%## ^# \# %&ƒ%#)##
#\# ' #) ## &#&( '
If the APS opens, look for the following:
Q „% #)
Q ‡ &\&
Flow Switch
†$#&&'' # &''* ‹+Š$# ' #
intended to do two things:
Q )## ' # _''# ' #`
Q )## %#'#&#'
temperatures entering and exiting the heat exchanger.
$# '( && % )‹+Š_$`$# ) ##
&('#%## %# #%## ¦#'' ###
& $# # %'## *&‹^&#
goes into a soft lockout if the rise reaches 63F.
#'' #&\#' %;
Q ~' #
Q $& # ƒ#&'* # )#' ^ %
11.1 when it is opened.
Q )& %
Q ^&™ %
FIGURE 14.4: CONTROLS LOCATION
COMBUSTION FAN
PUMP FUSE
24V FUSE
THERMAL FUSE
SENSOR
AIR
SWITCH
PRESSURE
SUMP
SWITCH
PROVING
SWITCH
FLOW
SENSOR
SUPPLY
SENSOR
RETURN
FLUE
TEMPERATURE
GAS VALVE