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6
control system pressure in an AIR ELIMINATING SYSTEM:
an automatic air vent is used to REMOVE air from the sys-
tem water. See illustration on page 5.
If system pressure needs further control, add an additional
tank or install a larger capacity tank.
Locate the tank near the boiler, as illustrated.
An automatic air vent should be installed in the top of the
boiler. See illustration on page 5.
2. 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 illustration on page 5 is required in large, multi-
story building installations, especially when high-head
pumps are used. The compression tank must be at the
boiler or between boiler and supply main pump(s).
3.On a hot water boiler installed above radiation level,the
boiler must be provided with a low water cut-off device at
the time of installation by the installer.
Flow Control Valve: When domestic hot water tankless heater is used,
a flow control valve should be installed in supply piping to heating sys
tem, as shown in illustration on page 5.
INSTALLATION INSTRUCTIONS FOR GXH LOW PRESSURE
STEAM BOILERS EQUIPPED WITH TANKLESS OR
PROVISION FOR TANKLESS AND McDONNELL & MILLER
TYPE 67 LOW WATER CUT-OFF.
STEAM CONTROLS ASSEMBLY AND INSTALLATION
INSTRUCTIONS
Steam kit components for Galaxy packaged models are packed
as follows:
A. 1. Low water cut-off control
2. Fittings
3. L.W.C.O. instruction sheet
B. 1. Pressure gauge
2. High pressure limit control
3. Water level gauge
4. Fittings
5. Instruction sheet and assembly drawing
6. Steam safety valve and
7. Drain cock
Assemble above components exactly as shown in steam controls
assembly. Two
1
/
" tappings are on right side of boiler for this
2
assembly. Two holes are pre-punched in jackets. For conve-
nience, start assembling in the following steps:
1
1
C. 1. Install
/
" x 5
/
" brass nipple onto tee of L.W.C.O.
2
2
1
2. Mount
1
/
" x 5
/
" brass nipple into lower boiler tapping by
2
2
rotating low water cut-off.
3. Assemble 90° brass tubing to tee adapter and L.W.C.O.
4. Install
1
/
" x 6" brass nipple and
2
boiler tapping.
5. Install syphon, high pressure limit and pressure gauge with
1
/
" brass fittings.
4
6. Install water level gauge (without glass) and its fittings.
7. Install water level glass, and mark the glass 648 mm (25
from the bottom of the steel boiler base for the water level.
(The steel boiler base should not be confused with a
combustible floor kit when making the 648 mm (25
measurement.)
8. Drain cock will be installed in return tee at the lower right side
of casting.
9. Safety valve and
3
/
" street coupling should be installed in
4
tapping on top of boiler.
3
/
" street coupling
4
1
/
" ×
5
/
" adapter tee in upper
2
8
1
/
2
PIPING A LOW PRESSURE STEAM BOILER
Boilers must be piped with good engineering practice and
must conform to the requirements of ANSI/ASME Boiler and Pres-
sure Vessel Code section IV and to the authority having
jurisdiction.
Notes:
A. Slant/Fin makes no recommendation, nor does Slant/Fin imply
that One Pipe Parallel and Counterflow Gravity Condensate
Return systems shown on page 7 are the preferred systems.
These systems are merely two examples of many possible sys-
tems. Determination of the proper system is based upon the
application and is therefore beyond the scope of this instruction.
B. The 457 mm (18") minimum height shown in figures 1-3, is the
minimum height between the top of the jacket of the boiler and
the 2
1
/
" x 12" header centerline in the supply piping from the
2
boiler. It must NOT be confused with the minimum height
between the water level and the lowest return bend of the steam
supply main. This height is "H" as shown in figures 2 and 3.
The minimum height of "H" must be at least equal to the sum of
the pressure drop of the system plus three times the friction loss
of the wet return, but not less than 457 mm (18") for a system
with a 0.9 kPa (
28" for a system with a 3.5 kPa (
C. Modern steam boilers are smaller in water content than the
boilers that they replace, therefore a mechanical return system
(pump, receiver, etc.) must be employed if conditions exist
such that uniform condensate return flow to the boiler cannot
be maintained.
Pocketing of condensate and the inability to maintain the cor-
rect minimum height between the steam supply main and the
water level in the boiler are but a few of the many conditions
that indicate the use of a mechanical return system.
Any use of a receiver and pump must be coordinated with the
makeup water and controlled by the boiler water level control
on the boiler. This description is typical of a boiler feed pump
as opposed to a condensate pump that pumps condensate
regardless of the water level in the boiler.
D. In any steam system one of the requirements is the removal of
air from the system. A mechanical return system in most cases
has an air vent on the receiver. A gravity return system has no
receiver, so provisions for air removal must be made on the
piping itself. A one pipe system has the air vents on the radia-
tion, the heat exchanger and near the end of the steam supply
main (see figures 2 and 3).
Main air vents should be located fifteen inches from the drop
and if possible eight inches above the pipe so that water
hammer does not damage the vent and render the vent
inoperable.
For more information on air vents, check with any manufac-
turer of steam accessories (steam traps, boiler feed pumps,
air vents, etc.).
E. Process water applications involving steam boilers requires
the use of heat exchangers. Any process application that
constantly uses fresh water into a steam boiler can and will
1
/
")
2
cause scaling with deposits forming in the boiler and sur-
rounding piping. This will damage the boiler.
F. If valves are used on the supply side of the boiler, the valve
")
port opening must be the same size as the surrounding pipe.
(Full flow type valves.)
G. Piping should provide a means of cleaning and flushing the
heating system of the sediment for safe, efficient operation.
3
/
"
4
1
/
" psi) steam pressure drop and not less than
8
/
psi) steam pressure drop.
1
2
GALAXY
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