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Part number 550-142-054/0411
69
GV90+ gas-fired water boiler — Boiler Manual
Inspect 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 page 13 of this manual for suggested location of expansion
tanks and air eliminators.
• Open-type — located above highest radiator or baseboard unit,
usually in the attic or closet. Has a gauge glass and overflow pipe
to a drain.
• Closed-type — welded gas tight and located above boiler. Tank is
partially filled with water, leaving an air cushion for expansion.
• Make sure this type of tank is fitted with a tank fitting, such
as the B & G Tank-Trol or Taco Taco-Trol. This fitting reduces
gravity circulation of air-saturated tank water back to the system
and prevents the air from bubbling up through the water as it
returns from the system.
• Do not use automatic air vents in systems with closed-type
tanks. The air will escape from the system instead of returning to
the tank. Eventually, the tank will waterlog and no longer control
pressurization. The boiler relief valve will weep frequently.
•
Diaphragm- or bladder-type — welded gas tight with a rubber
membrane to separate the tank pressurizing air and the water. May
be located at any point in the system, but most often found near
the boiler.
• Systems with this type of expansion tank require at least one
automatic air vent, preferably located on top of an air elimina-
tor, as shown in examples in this manual.
2. If relief valve has tended to weep frequently, the expansion tank may
be waterlogged or undersized.
• Closed-type tank — tank is most likely waterlogged. Install a
tank fitting if not already installed. Then check fill level per fitting
manufacturer’s instructions. If fill level is correct, check tank size
against manufacturer’s instructions. Replace with a larger tank if
necessary.
• Diaphragm- or bladder-type — first, check tank size to be sure it
is large enough for the system. If size is too small, add additional
tank (or tanks) as necessary to provide sufficient expansion. If tank
size is large enough, remove tank from system and check charge
pressure (usually 12 PSIG for residential applications). If tank won’t
hold pressure, membrane has been damaged. Replace tank.
Inspect air openings
1. Verify that combustion and ventilation air openings to the boiler room
and/or building are open and unobstructed. Check operation and wir-
ing of automatic combustion air dampers, if used.
2. Verify that boiler vent discharge and air intake are clean and free of
obstructions.
Inspect vent system and air piping
1. Visually inspect entire flue gas venting system and combustion air pip-
ing for blockage, deterioration or leakage. Repair any joints that show
signs of leakage in accordance with vent manufacturer’s instructions.
When air is ducted to boiler, verify that air inlet hose is connected and
properly sealed.
Failure to inspect for the above conditions and have them
repaired can result in severe personal injury or death.
Inspect boiler heating surfaces
The boiler contains ceramic fiber and
fiberglass materials. Use care when han-
dling these materials per instructions
on page 107 of this manual. Failure to
comply could result in severe personal
injury.
Electrical shock hazard — Turn off
power to the boiler before any service
operation
on the boiler except as noted
otherwise in this instruction manual.
Failure to turn off electrical power could
result in electrical shock, causing severe
personal injury or death.
1. Remove the jacket top panel and jacket front panel
after turning off power to the boiler.
2. Remove the two nuts retaining the
flueway in-
spection port cover
(page 3, item g). Remove the
flueway inspection port cover.
3. Inspect the boiler vent outlet area and heating
surfaces by looking through the opening.
4. If the boiler flueways show accumulation of soot,
follow
Cleaning boiler heating surfaces on
page 72 to remove the blower housing and clean
the boiler. If there is evidence of a large accumula-
tion of rusty scale deposits, check the temperature
mixing system.
5. Replace the
flueway inspection port cover.
Inspect igniter
1. Verify igniter operation — Look through blower
observation port (see Figure 78). Access the blower
by removing the boiler jacket front panel if not
already removed.
Annual start-up (continued)
Figure 78 Igniter observation port in blower