AERCO BMK 3.0 LN Nat. Gas Jan 2011 - Manual (Page 23)

INSTALLATION
2-11
2.10.11 FAULT RELAY
The f ault r elay is a s ingle pol e do uble thr ow
(SPDT) relay ha ving a normally op en and
normally c losed s et of r elay c ontacts that ar e
rated for 5 am ps at 12 0 VAC and 5 amps at 30
VDC. T he r elay e nergizes whe n an y f ault
condition occurs and remains energized until the
fault is c leared an d th e CLE AR button is
depressed. T he f ault r elay c onnections ar e
shown in Figure 2-11.
2.11 AUXILIARY RELAY CONTACTS
Each Bo iler is equ ipped w ith a s ingle po le
double t hrow ( SPDT) r elay th at is ener gized
when th ere is a dem and f or heat and de-
energized after the d emand for heat is satisfied.
The relay is provided for the control of auxiliary
equipment, such as pumps and louvers, or c an
be used as a Boiler status indictor (firing or not
firing). Its contacts are rated for 120 VAC @ 5
amps. Ref er to F igure 2- 11 t o l ocate the AUX
RELAY terminals for wiring connections.
2.12 FLUE GAS VENT INSTALLATION
The minimum allo wable vent diam eter f or a
single Benchmark 3.0 Boiler is 8 inches.
The AERCO Benchmark Ventin g a nd
Combustion Air G uide, GF-2050, m ust be
consulted bef ore an y f lue gas ven t or in let air
venting is des igned or i nstalled. U/ L l isted,
positive pr essure, watertight v ent m aterials as
specified in AERCO’s G F-2050, m ust be us ed
for safety and code compliance. Since the unit is
capable of discharging low temperature exhaust
gases, h orizontal s ections of the f lue vent
system must be pitc hed bac k to the unit a
minimum of 1/4 inc h per f oot to avoid
condensate po oling a nd allo w f or pr oper
drainage.
The c ombined pr essure dr op of ve nt a nd
combustion air s ystems must not ex ceed 1 40
equivalent feet of 8 inch ducting. Fittings as well
as pipe lengths must be calculated as part of the
equivalent length.
For a n atural draft installation the draft must not
exceed ±0.25 inch W.C. These f actors must be
planned i nto t he vent ins tallation. If the
maximum allowable equivalent lengths of piping
are exceeded, the unit will not oper ate properly
or reliably.
For Mas sachusetts boiler ins tallations, t he
Heatfab D ivision of the Se lkirk Cor poration
provides vent s ystems whic h c onform to all
applicable r equirements for ins tallations within
the C ommonwealth of Ma ssachusetts. Con tact
information for this supplier is as follows:
Selkirk Corporation
Heatfab Division
130 Industrial Blvd.
Turners Falls, MA 01376
Phone: 1-800-772-0739
www.heat-fab.com
2.13 COMBUSTION AIR
The AERCO Be nchmark Venting and C ombus-
tion Air G uide, G F-2050 MUST be c onsulted
before
any flue or combustion supply air venting
is des igned or im plemented. C ombustion a ir
supply is a d irect r equirement of ANSI 22 3.1,
NFPA-54, and local codes. These codes should
be c onsulted bef ore a p ermanent des ign is
determined.
The c ombustion a ir m ust be f ree of c hlorine,
halogenated h ydrocarbons, or other c hemicals
that can become hazardous when used in gas-
fired eq uipment. Com mon s ources of t hese
compounds ar e s wimming poo ls, de greasing
compounds, plastic processing and refrigerants.
Whenever the environment contains these types
of c hemicals, c ombustion air m ust be s upplied
from a c lean area out doors f or the pr otection
and longevity of the equipment.
The AER CO Benchmark 3.0 Boiler is U L listed
for 100% s ealed c ombustion. It c an als o be
installed us ing r oom air , provided ther e is an
adequate s upply. ( See p aragraph 2.1 3.3 f or
more information concerning sealed combustion
air). If the s ealed c ombustion air op tion is no t
being used, an in let s creen will b e at tached at
the air inlet on the top of the unit
The more c ommon methods of s upplying
combustion air are o utlined b elow. F or m ore
information c oncerning c ombustion air , c onsult
the AERCO B enchmark Ventin g an d
Combustion Air Guide, GF-2050.
2.13.1 Combustion Air From Outside the
Building
Air s upplied f rom outs ide the building m ust be
provided through two permanent openings. Each
opening must have a free area of not less than
one s quare i nch f or eac h 4000 BTU/H bo iler
input. T he f ree ar ea m ust tak e into ac count
restrictions such as louvers and bird screens.