Specifications

Part number 550-100-090/0809
95
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
MAINTENANCE & SPECIFICATIONS
Annual startup (continued)
Inspect automatic air vents and air separators. Remove air vent caps 4.
and briefly press push valve to flush vent. Reinstall caps. Make sure
vents do not leak. Replace any leaking vents.
Check system water chemistry (pH, hardness and inhibitor level). See 5.
page 31.
Check expansion tank
Expansion tanks provide space for water to move in and out as the 1.
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 11 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.
If relief valve has tended to weep frequently, the expansion tank may 2.
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 ignition electrode
Remove the ignition electrode from the boiler heat 1.
exchanger access cover.
Remove any white oxides accumulated on the 2.
ignition electrode using steel wool. If the ignition
electrode cannot be cleaned satisfactorily, replace
ignitor with a new one.
Reinstall ignition electrode, making sure gasket is 3.
in good condition and correctly positioned.
Make sure the electrodes are parallel to each 4.
other.
Check ignition wiring
Check ignition cable electrical resistance. A good 1.
cable will have resistance between 900 and 1000
ohms. Replace if not acceptable.
Inspect boiler ground wire from heat exchanger 2.
access cover to ground terminal strip.
Verify all wiring is in good condition and securely 3.
attached.
Check ground continuity of wiring using continu-4.
ity meter.
Replace ground wires if results are not satisfac-5.
tory.
Check all boiler wiring
Inspect all boiler wiring, making sure wires are in 1.
good condition and securely attached.
Check control settings
Use the U-Control display to navigate through all 1.
settings. Adjust settings if necessary.
Check settings of external limit controls (if any) 2.
and adjust if necessary.
Perform startup and checks
Start boiler and perform checks and tests specified 1.
in this manual.
Verify cold fill pressure is correct and that operating 2.
pressure does not go too high.
Complete the check-out procedure on 3. page 38.