5
2. Boiler Blowdown Valve/Drain
A boiler blowdown valve is provided on the front right
side of the pressure vessel to completely drain the boiler
as required, and for periodic bottom blowdown.
3. Feedwater Make-Up
A valve is provided on the front centerline of the pressure
vessel near the bottom for connection to the system
make-up and/or condensate return.
4. Exhaust Gas Vent
The connection for the stack or breaching is located at
the rear near the top of the boiler. This is a sleeve
connection, with the opening in accordance with the
nominal dimension and rating sheets.
C. Boiler Trim
The following are factory installed standard trim and
control items. Trim items are provided in accordance with
the ASME Code and the controls and are UL listed.
1. Relief Valve
In compliance with the ASME Code, a steam boiler
pressure relief valve(s) is provided. Size and quantity are
determined by the valve setting, valve capacity, and the
ASME Code. These may be shipped loose to prevent
possible damage during shipment.
2. Water Column
Factory mounted and piped complete with gauge glass,
gauge glass drain valve, gauge glass isolation valves,
column drain valve, and a minimum of 1” equalized
piping and crosses for inspection and clean-out.
3. Low Water Cut-Off
To prevent burner operation whenever a low water
condition occurs, an electronic probe-sensing device, or
float operated control is furnished in the water column.
This device is wired in series to the burner combustion
safeguard control to prevent burner operation whenever
a low water condition occurs.
4. Pump Control
When a probe sensing main level control is furnished,
two stainless steel probes are furnished in the water
column to provide pump ON/OFF operation for water
make-up. These probes are wired to an electronic
interlock relay for pump or water valve control.
However, if the column is a float-actuated device, a
snap acting single pole single throw switch activates a
pump contactor for ON/OFF pump or solenoid valve
operation.
5. Auxiliary Low Water Cut-Off
An additional control, separate from the primary low
water control is provided to prevent burner operation if a
low-low water condition exists. This device is an internal
probe control located on the top of the pressure vessel,
and requires manual reset whenever a low-low water
condition occurs.
6. Steam Pressure Gauge
A 3-1/2" dial pressure gauge is furnished as standard.
The range of the gauge will be in accordance with the
safety valve setting, based on 1.5 times the valve
setting for high-pressure units, and two times the design
pressure of low-pressure units.
7. Steam Pressure Controls
9-1/2 to 25 Horsepower
Two controls are furnished; one for ON/OFF
operation while the other is to prevent burner
operation if excess steam pressure is sensed and
requires a manual reset.
30 to 50 Horsepower
Three (3) controls are supplied as standard. One
control provides for ON/OFF operation in response
to system demand and one is provided as a safety
lockout with a manual reset requirement. The third
control is for burner positioning at either low fire or
high fire relative to steam demand.
8. Valves
Standard valve piping package, 9-1/2 to 30 horsepower,
consists of: one (1) main steam stop valve, one (1)
feedwater stop valve, one (1) feedwater spring loaded
check valve, one (1) quick open bottom blowdown
valve, and one (1) slow open blowdown valve. Valves
for larger sizes are not provided unless requested.
D. Fuel Burning System
The factory-assembled boiler is furnished with a UL
approved fuel burning forced draft packaged system.
The packaged system is mounted and wired integral
with the front centerline of the boiler.
1. Burner Type
The forced draft burner is designed for Natural or LP
gas only.
2. Burner Operation
The burner is designed to operate in an ON/OFF mode
for sizes 9-1/2 to 25 horsepower and LOW/HIGH/OFF
for boilers 30 to 50 horsepower. Modulating burners are
optional.
