Weil-McLain CGi 4 Series Manual page 47

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
10b
Service & maintenance – annual start-up
Check/test . . .
Gas piping
1. Sniff near floor and around boiler area for any indica-
tion of a
gas leak
2.
Test gas piping using bubble test,
manual, if there is any indication of a leak.
Cold fill and operating pressures
1. While the system is cold, note the
on the boiler pressure/temperature gauge. Verify that
cold fill pressure is correct.
2.
Watch the pressure
ensure pressure rise is normal. Too high a rise would
indicate a waterlogged or undersized expansion tank.
Air vents and air elimination
1. Inspect automatic air vents (if used). Also inspect air
separators to ensure they are operational.
2. The cap must be unscrewed one turn to allow air to
escape.
3. See
Figure 34
and briefly push valve
A
the valve seat.
4. Replace cap
then unscrewing one turn.
Figure 34 Automatic air vent, typical
Limit controls and cutoffs
1. Inspect and test the boiler limit control. Verify operation
by turning control set point below boiler temperature.
Boiler should cycle off. Return dial to original setting.
2. Inspect and test additional limit controls or low water
cutoffs installed on system.
Expansion tank
1. Expansion tanks provide space for water to move in
an 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
Part Number 550-142-302/0124
.
per Section
pressure reading
as the boiler and system heat up to
. If the air vent is leaking, remove cap
and then release to clean
B
by twisting all the way onto valve
A
Boiler Manual
type. See Section
best location of expansion tanks and air elimina-
tors.
Open-type
baseboard unit, usually in the attic or closet. Has
a gauge glass and overflow pipe to a drain.
Closed-type
of this
5
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
Taco Taco-Trol. This fitting reduces gravity
circulation of air-saturated tank water back
to the system and prevents the air from bub-
bling up through the water as it returns from
the system.
•
Do not use automatic air vents in systems
with closed-type tanks.
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
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.
and
B
• Systems with this type of expansion tank
require at least one
erably located on top of an air eliminator, as
shown in examples in manual Section
2. If relief valve has tended to weep frequently,
the expansion tank may be waterlogged or
undersized.
Closed-type tank
logged. Install a tank fitting if not already in-
stalled. Then check fill level per fitting manufac-
turer'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
size to be sure it is large enough for the sys-
tem. If size is too small, add additional tank(s)
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.
(cont.)
of this manual for suggested
4
— located above highest radiator or
— welded gas tight and located
, such as the B & G Tank-Trol or
The air will escape
— welded gas tight
automatic air vent
— tank is most likely water-
— first, check tank
, pref-
.
4
47