3
FEATURES
3.1
ELECTRONIC IGNITION
"RS Mk II". boilers. have. automatic. ignition.
(with.no.pilot.light),.so.they.have.an.SM.191.1.
electronic.control.and.protection.device.with.
a.built-in.transformer.(fig..15)..
Ignition.and.flame.detection.are.controlled.by.
two.sensors.at.the.ends.of.the.burner..
Ignition. takes. place. directly. in. the. burner;.
the.utmost.safety.is.guaranteed,.with.tripping.
times. of. within. 2. seconds. in. the. event. that.
the.flame.accidentally.goes.out.or.there.is.no.
gas.supply..
3.1.1
Functioning cycle
Before.turning.on.the.boiler.use.a.volt.meter.
to. check. that. the. terminal. board. has. been.
wired.up.correctly,.complying.with.the.phase.
and.neutral.positions.shown.in.the.diagram..
Press. the. switch. on. the. control. panel.. At.
this. point. the. boiler. will. start. up,. sending.
a. current. discharge. through. the. SM191.1.
programmer. to. the. ignition. electrode. while.
opening.the.gas.valve..
When. the. gas. pressure. is. insufficient,. the.
pressure. switch. does. not. enable. the. start-
up. cycle. and. the. insufficient. gas. pressure.
warning. signal. is. enabled.. Burner. ignition.
normally.takes.1.to.2.seconds..
In. the. event. that. ignition. fails,. the. boiler.
shutdown.signal.will.be.triggered..Let.us.sum.
up.how.this.can.happen:
–. Air in the gas pipes
. The. boiler. performs. the. cycle. normally,.
sending. voltage. to. the. ignition. electrode,.
which. continues. to. discharge. for. a. maxi-
mum. of. 8. seconds.. If. the. burner. is. not.
ignited,.the.boiler.shuts.down..
. This.may.occur.the.first.time.the.boiler.is.
started.up.or.when.it.has.been.inactive.for.
some.time.and.there.is.air.in.the.pipes..It.
may. be. caused. by. failure. to. open. the. gas.
valve.due.to.an.interruption.in.the.electri-
cal.coil..
–. Ignition electrode fails to
discharge
. The. gas. valve. to. the. burner. normally.
opens;. if. this. does. not. occur. within. 8.
seconds.the.boiler.will.shut.down..
. This.may.be.the.result.of.an.interruption.in.
the. electrode. cable,. or. the. cable. may. not.
be.properly.fastened.to.terminal.10;.or.the.
boiler's.transformer.may.have.been.burnt.
out.
–. The flame is not detected
. The.electrode.continues.to.discharge.even.
though.the.burner.is.already.ignited..After.
about. 8. seconds. the. discharge. will. stop.
and.the.burner.will.be.shut.down,.while.the.
device's.shutdown.indicator.light.will.come.
on..
. This.occurs.if.phase.and.neutral.have.not.
54
2
4
FIRST.GAS.
PRIMA
SOLENOID.VALVE
ELETTROVALVOLA
GAS
MINIMUM.GAS
VALVOLA GAS
PRESSURE.VALVE
DI MINIMA
KEY
1.. SM.191.1.device
2. Interference.filter
be. connected. properly. on. the. terminal.
board.. The. detection. electrode. cable. may.
be. interrupted. or. the. electrode. itself. may.
be. grounded;. the. electrode. may. be. worn.
and.require.replacement.
NOTE: if the device shuts down, press the
illuminated pushbutton only after waiting
at least 20 seconds from when the indica-
tor light came on, or the device will not be
released.
3.1.2
Ionisation circuit
The.ionisation.circuit.may.be.controlled.using.
a.micro-ammeter.with.a.dial.or,.better.yet,.a.
digital.reading,.with.a.scale..of.0.to.50.µ.
The. micro-ammeter's. terminals. must. be.
wired. up. to. the. detection. electrode. cable. in.
1
3
MINIMUM.GAS
PRESSOSTATO
PRESSURE.SWITCH
GAS DI MINIMA
SECOND.GAS.
SECONDA
ELETTROVALVOLA
SOLENOID.VALVE
GAS
3.. Ignition.electrode
4.. Detection.electrode
series..During.regular.operation.the.reading.
fluctuates. around. 6÷12. µ. .. The. minimum.
ionisation.current.at.which.the.device.may.be.
shut.down.is.around.1.µ...
If. this. occurs,. check. that. there. is. proper.
electrical. contact. and. check. the. end. of. the.
electrode.and.its.ceramic.guard.for.wear.
3.2
OPPOSED INSTALLATION
OF TWO BOILERS
On. request,. accessories. may. be. supplied. to.
permit.opposed.installation.of.two.boilers.so.
as. to. reduce. overall. dimensions. and. permit.
easy.connection.with.the.flue.by.allowing.flue.
gases.to.be.evacuated.through.a.single.duct.
(fig..16-17)..
Table 2. shows. the. dimensions. of. the. two.
combined.boilers.and.stack.diameter.
Fig..15