Sentry S-120 Installation And Operating Instructions Manual - page 13
BOILER ROOM AIR SUPPLY AND VENTILATION
An ample supply of air is required to obtain combustion and
ventilation. ALL AIR COMES FROM OUTSIDE, directly through
wall openings to the boiler or through unsealed openings
around windows, doors, etc. in the whole building. When build-
ings are insulated, caulked and weather stripped, now or later
on, direct openings to outside may be required and should be
provided. If the boiler is not near an outside wall, air may be
ducted to it from outside wall openings.
Provisions for combustion and ventilation air must be made in
accordance with section 5.3, Air for Combustion and
Ventilation, of the National Fuel Gas Code, ANSI Z223.1-latest
edition or CSA B149.1 latest edition for natural gas and
propane, or applicable provisions of the local building codes.
The following recommendation applies to buildings of energy-
saving construction, fully caulked and weather stripped:
INSTALLATION IN ENCLOSED BOILER ROOM REQUIRES
TWO UNOBSTRUCTED OPENINGS FOR PASSAGE OF AIR
INTO THE BOILER ROOM:
1. Air drawn horizontally from outdoors DIRECTLY through
an outside wall; one louvered opening near the floor and
one louvered opening near the ceiling, each opening with a
minimum FREE air passage area of 550 mm
2
per kW (1
square inch per 4000 BTUH) of total appliances’ input.
2.
Air drawn horizontally through HORIZONTAL DUCTS;
one opening near the floor and one opening near the
ceiling, each opening with a minimum FREE air passage
area of 1100 mm
2
per kW (1 square inch per 2000 BTUH)
of total appliances’ input.
3. Air drawn VERTICALLY from outdoors; one opening at
the floor and one opening at the ceiling, each opening with
a minimum FREE air passage area of 550 mm
2
per kW (1
square inch per 4000 BTUH) of total appliances’ input.
4. Air drawn from inside the building; one opening near the
floor and one opening near the ceiling, each opening with a
minimum FREE air passage area of 2200 mm
2
per kW (1
square inch per 1000 BTUH) of total appliances’ input.
IF BOILERS ARE INSTALLED ADJACENT TO OTHER FUEL
BURNING EQUIPMENT, THE AREA OF FREE OPENINGS
MUST BE APPROPRIATELY INCREASED TO ACCOMMODATE
THE ADDITIONAL LOAD.
Openings must never be reduced or closed. If doors or
windows are used for air supply, they must be locked open.
Protect against closure of openings by snow and debris.
Inspect frequently.
No mechanical draft exhaust or supply fans are to be used in or
near the boiler area.
The flow of combustion and ventilating air to the boiler must
not be obstructed.
WATER PIPING
I. CIRCULATING SYSTEMS
A. Hot water heating systems include a water circulating
pump which may be mounted on the supply or return
side of the boiler based on system design – See figure 8.
II. AIR CONTROL SYSTEM
A. DIAPHRAGM-TYPE COMPRESSION TANKS are used to
control system pressure in an AIR ELIMINATING SYS-
TEM: an automatic air vent is used to REMOVE air from
the system water. See figure 8. If system pressure needs
further control, add an additional tank or install a larger
capacity tank. Locate the tank near the boiler, as
illus trated. An automatic air vent should be installed in the
top of the boiler or air purger. See figure 11.
B. PUMP LOCATION — Locating low-head pump(s) on
return to boiler is acceptable for smaller boiler sizes in
resi dences of one or two stories. The alternate pump
location shown in figure 8 is required in large, multi-story
building installations, especially when high-head pumps
are used. The expansion tank must be at the boiler or
between boiler and supply main pump(s).
IMPORTANT: Hot water heating systems containing high
water volume, such as would occur with cast-iron radia-
tion, require special care with air elimination.
The circulating pump should be located on the boiler
supply pipe and the expansion tank and air scoop should
be located near the pump suction.
C. On a hot water boiler installed above radiation level, the
boiler must be provided with a low water cutoff device at
the time of installation by the installer.
I. FILLING AND VENTING WATER SYSTEMS
A. Fill the system with water. Vent or purge off air.
B. Fire the boiler as soon as possible (see following warning
and instructions) and bring water temperature to at least
82°C (180°F), while circulating water in the system.
C. Vent air and add water as needed to achieve operating
pressure on boiler gauge. Pressure must be between
approximately 83 kPa (12 psi) (cold water) and 172 kPa
(25 psi) (at water temperature setting of high limit con-
trol), for boilers equipped with 207 kPa (30 psi) relief
valves. Boilers rated for a higher pressure and equipped
with a matching relief valve may operate at a higher pres-
sure, but no higher than 34 kPa (5 psi) below the relief
valve opening pressure.
D. Check for and repair any leaks before placing system in ser-
vice.
Before firing boiler, make these checks:
1. System is full of water. Air is vented or purged.
2. Relief valve is installed in accordance with the ASME Boiler
Pressure Vessel Code, Section IV. Valve opening is not
closed or reduced in size.
OPERATING INSTRUCTIONS
Figure 11. Piping Arrangement
13
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