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Gas-Fired Boiler Installation
14
2. Gas connection has been made, pressure tested
for leakage, and the line purged of air. Make
sure all required bleeds and vents have been in-
stalled.
3. Water connections are complete, and the boiler
and system have been filled and purged of air.
4. The boiler must be connected to a 120 volt / 60
Hz power source with proper polarity and dedi-
cated machinery ground. Provide a disconnect
having adequate overload protection.
5. Combustion air openings are not obstructed in
any way and have adequate capacity. (See Sec-
tion 3.5)
6. The boiler is placed the proper distance from
any combustible walls or substances, in accor-
dance with Section 3.3.3.
7. Relief valves have been properly piped to floor
drains.
3.11
SAFETY CHECKS
The following checks of safety systems must be
made before putting the boiler into normal opera-
tion.
Before firing the boiler refer to Sections 4.1 and 4.2
for information on the use of the controls, lighting,
and shut-down procedures.
WARNING!
Never attempt to operate a boiler that has failed to
pass all the safety checks described below.
WARNING!
After checking controls by manual adjustment, make
sure they are always reset to their proper settings.
3.11.1 Test of Ignition Safety System
Test the ignition system safety shutoff as follows:
1. Close the gas cock which is downstream from
the two safety shut off valves (in the vertical
line).
2. With the main gas cock (inlet manual gas valve)
open and the pilot gas cock open, the burner
should be cycled on. After all the safety limits
on gas pressure, water flow and temperature are
satisfied, the blower will run and pre-purge the
boiler.
3. When air flow is established, the ignition trans-
former and pilot will operate. Both functions
will be indicated by separate indicator lights on
the flame safeguard.
4. If a satisfactory pilot is established, the spark
will terminate and the pilot will remain on,
alone, for 10 seconds.
5. After 10 seconds, the "Main” light on the flame
safeguard will go on; gas will not flow since the
downstream cock is closed. The "Pilot" will
remain on, along with the "Main Gas", for an-
other 10 - 15 seconds and then go out. Since the
gas cock is closed, at this point there will be no
main flame signal and the flame safeguard pro-
grammer will assume a “Flame Failure” and go
to a "lockout" mode. Lockout will require man-
ual reset of the flame safeguard.
After completing this test, turn off the boiler and
reopen the downstream gas cock.
3.11.2 Test of Low Water Cut-off
The boiler is furnished with a flow-switch-type low
water cutoff in the outlet nozzle. Test as follows:
Operation of the switch can be checked by first turn-
ing the boiler off and then turning the system pump
off, stopping water flow in the system. After turn-
ing off the pump, turn the boiler back on. It should
not operate, and a red indicator for "Low Water" or
"Water Flow" should be illuminated. Do not shut
the pump off while the boiler is operating.
Perform appropriate tests on any external probe-type
low water cutoff.
3.11.3 Test of Limit Controls
Fire the boiler and test the high limit control as fol-
lows:
With the main burner operating, turn down the tem-
perature setting on the "high-limit" thermostat until