AI
SERIES STEAM BOILER WITH T100 CONTROL
INSTALLATION INSTRUCTIONS
4211-195 05-22-12
Page 23
APPENDIX 2: PRESSURE CONTROL ASSEMBLY
The AI boiler comes equipped with two pressure switches, wired in series, to control boiler heating. The primary switch automatically closes when the
boiler’s internal pressure is low and opens when the pressure is high, turning the heating elements on and off as needed to create steam and maintain
boiler pressure. The second switch is a safety control: it remains closed during normal operation but, should the primary switch fail and the boiler pres-
sure increase too much, the safety switch will open, turning off the heating elements. The safety switch will remain open until the pressure has dropped
and its reset button is manually pushed.
If the safety switch opens, there may be a problem with the primary switch. Check the primary switch operation by creating pressure in the boiler. Also
verify that the pressure gauge shows a smooth and steady pressure increase. If the primary switch does not open at the correct pressure or the gauge
shows rapid pressure increases, release all pressure and remove line voltage from the boiler and clean or repair the pressure control assembly as
needed.
Adjust the pressure switches as shown below.
Turn the thumbwheel on the primary switch
and set the bar to about 4 psi
Turn the screw on top of the safety switch to set the switch to a
point higher than the primary switch setting and lower than the
safety relief valve setting.
We recomend setting it to 10 psi.
A
fi
tting is supplied to allow connecting a second pressure gauge to easily replace
the supplied gauge or to connect a second gauge for inspection. A ball valve is
supplied assist with gauge changes; the valve should be left open during normal operation.
PSI
4
8
12
0.3
0.6
0.8
BAR
PSI
4
8
12
0.3
0.6
0.8
BAR
