that.the.tap.is.closed.(fig..4).
2.2.2 D.H.W. production on
“DUETTO” version (fig. 5)
To. adjust. water. flow. use. the. water.
pressure.gauge.flow.regulator.(fig..5):
-..Turn. clockwise. and. the. regulator.
reduces.water.supply.consequently.
increasing. the. relevant. temperatu-
re.
-..Turn. counter-clockwise. and. the.
regulator. increases. water. supply.
consequently.reducing.the.relevant.
temperature.
2.2.3 Characteristics of feedwater
To.prevent.lime.scale.and.damage.to.
the. tap. water. exchanger,. the. water.
supplied.should.have.a.hardness.of.no.
more.than.20°F..
In.all.cases.the.water.used.should.be.
tested. and. adequate. treatment. devi-
ces.should.be.installed..
To. prevent. lime. scale. or. deposits. on.
the. primary. exchanger,. the. water.
used. to. supply. the. heating. circuit.
should. must. be. treated. in. accordan-
ce. with. UNI-CTI. 8065. standards.. It. is.
absolutely. essential. that. the. water. is.
to.be.treated.in.the.following.cases:
–. Very. extensive. systems. (with. high.
contents.of.feedwater).
–. Frequent.addition.of.makeup.water.
into.the.system.
–. In.case.it.is.necessary.to.empty.the.
system.either.partially.or.totally.
2.3
CONNECTING UP FLUE
The. flue. is. of. fundamental. impor-
tance. for. the. proper. operation. of.
the.boiler;.if.not.installed.in.compli-
ance.with.the.standards,.starting.the.
boiler.will.be.difficult.and.there.will.
be. a. consequent. formation. of. soot,.
condensation.and.encrustation..
A.flue.therefore.must.satisfy.the.fol-
lowing.requirements:
–. be. constructed. with. waterproof.
materials.and.resistant.to.smoke.
temperature.and.condensate;
–. be. of. adequate. mechanical. resil-
ience.and.of.low.heat.conductivity;
–. be. perfectly. sealed. to. prevent.
cooling.of.the.flue.itself:
–. be.as.vertical.as.possible;.the.ter-
minal.section.of.the.flue.must.be.
fitted.with.a.static.exhaust.device.
that. ensures. constant. and. effi-
cient. extraction. of. products. gen-
erated.by.combustion;
–. to.prevent.the.wind.from.creating.
pressure.zones.around.the.chim-
ney. top. greater. than. the. uplift.
force. of. combustion. gases,. the.
exhaust. outlet. should. be. at. least.
0.4.m.higher.than.structures.adja-
cent. to. the. stack. (including. the.
roof.top).within.8.m;
–. have. a. diameter. that. is. not. infe-
rior. to. that. of. the. boiler. union:.
square. or. rectangular-section.
flues.should.have.an.internal.sec-
tion. 10%. greater. than. that. of. the.
boiler.union;
–. the.useful.section.of.the.flue.must.
conform.to.the.following.formula:
. S. resulting..section.in.cm
2
. K. reduction.coefficient.for.liquid.
fuels:.0.024
. P. boiler.input.in.Kcal/h
. H. height. of. the. flue. in. meters.
measured. from. the. flame.
axis.to.the.flue.outlet.into.the.
atmosphere.. When. . dimen-
sioning. the. flue,. the. effective.
height. of. the. flue. in. meters.
must. be. considered,. meas-
ured.from.the.flame.axis.to.the.
top.of.the.flue,.reduced.by:
. .
–. 0.50.m.for.each.change.of.di-
rection.of.the.connection.un-
ion.between.boiler.and.flue;
. .
–. 1.00.for.each.horizontal.me-
tre.of.the.union.itself.
Our.boilers.are.the.B
23
.type.and.do.
not.need.any.particular.connections.
other. than. the. one. to. the. flue. as.
described.above.
.
2.4
FUEL ADDUCTION (figs. 7 - 7/a)
The. fuel. can. be. fed. into. the. thermal.
group. sideways,. the. ducts. must. be.
REGOLATORE
DI PORTATA
71
FLOW.
REGULATOR
Fig..5
. .
. .
P
. S. =. K
. .
. .
√H
