Maintenance, Flue vent system and air piping, Check water system – Lochinvar Kight XL 400-801 User Manual
Page 51: Check expansion tank, Check boiler relief valve

51
9
Maintenance
(continued)
Flue vent system and air piping
1. Visually inspect the entire fl ue gas venting system for
blockage, deterioration or leakage.
2. Verify that boiler vent discharge and air intake openings
are clean and free of obstructions.
Failure to inspect for the above conditions 
and have them repaired can result in 
severe personal injury or death.
Check water system
1. Verify all system components are correctly installed and
operational.
2. Check the cold fi ll pressure for the system. Verify it is
correct (must be a minimum of 12 psi (82.7 kPa)).
3. Watch the system pressure as the boiler heats up (during
testing) to ensure pressure does not rise too high.
Excessive pressure rise indicates expansion tank sizing or 
performance problem.
4. Inspect automatic air vents and air separators. Remove
air vent caps and briefl y press push valve to fl ush vent. 
Replace caps. Make sure vents do not leak. Replace any 
leaking vents.
Check expansion tank
1. Expansion tanks provide space for water to move in
and out as the heating system water expands due to 
temperature increase or contracts as the water cools. 
Tanks may be open, closed or diaphragm or bladder 
type. See Section 3 - Hydronic Piping for suggested best 
location of expansion tanks and air eliminators.
Check boiler relief valve
1. Inspect the relief valve and lift the lever to verify fl ow.
Before operating any relief valve, ensure that it is piped 
with its discharge in a safe area to avoid severe scald 
potential. Read Section 3 - Hydronic Piping before 
proceeding further.
Safety relief valves should be re-inspected 
AT LEAST ONCE EVERY THREE YEARS, 
by a licensed plumbing contractor or 
authorized inspection agency, to ensure 
that the product has not been affected by 
corrosive water conditions and to ensure 
that the valve and discharge line have not 
been altered or tampered with illegally. 
Certain naturally occurring conditions may 
corrode the valve or its components over 
time, rendering the valve inoperative. Such 
conditions are not detectable unless the valve 
and its components are physically removed 
and inspected. This inspection must only 
be conducted by a plumbing contractor 
or authorized inspection agency – not by 
the owner. Failure to re-inspect the boiler 
relief valve as directed could result in 
unsafe pressure buildup, which can result in 
severe personal injury, death, or substantial 
property damage.
Following installation, the valve lever must 
be operated AT LEAST ONCE A YEAR to 
ensure that waterways are clear. Certain 
naturally occurring mineral deposits may 
adhere to the valve, rendering it inoperative. 
When manually operating the lever, water 
will discharge and precautions must be 
taken to avoid contact with hot water and 
to avoid water damage. Before operating 
lever, check to see that a discharge line is 
connected to this valve directing the fl ow 
of hot water from the valve to a proper 
place of disposal. Otherwise severe personal 
injury may result. If no water fl ows, valve 
is inoperative. Shut down the boiler until a 
new relief valve has been installed.
2. After following the above warning directions, if the relief
valve weeps or will not seat properly, replace the relief 
valve. Ensure that the reason for relief valve weeping is 
the valve and not over-pressurization of the system due to 
expansion tank waterlogging or undersizing.
ƽ WARNING
ƽ WARNING
ƽ WARNING
Outdoor Knight XL Installation & Operation
Manual
