Expansion Tank - Weil-McLain Gold CGs-4E Manual

CGs-4E Gas-Fired Water Boiler — Boiler Manual
GOLD
10b
Service & maint. — annual start-up
❏
Gas piping
1. Sniff near floor and around boiler area for any in-
dication of a
Test gas piping using bubble test,
2.
of this 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.
Watch the pressure
2.
up to ensure pressure rise is normal. Too high a rise
would indicate a waterlogged or undersized expan-
sion 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
A
and briefly push valve
the valve seat.
4. Replace cap
and then unscrewing one turn.
Figure 22
Limit controls and cutoffs
1. Inspect and test the boiler limit control. Verify op-
eration 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.
40
Check/test . . .
gas leak
.
as the boiler and system heat
Figure 22
. If the air vent is leaking, remove cap
B
and then release to clean
A
by twisting all the way onto valve
Automatic air vent, typical

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
type. See Section
location of expansion tanks and air eliminators.
5
per Section
Open-type
baseboard unit, usually in the attic or closet. Has a
gauge glass and overflow pipe to a drain.
Closed-type
pressure reading
boiler. Tank is partially filled with water, leaving an
air cushion for expansion.
•
•
Diaphragm- or bladder-type
with a rubber membrane to separate the tank pres-
B
surizing air and the water. May be located at any
point in the system, but most often found near the
boiler.
•
2. If relief valve has tended to weep frequently, the ex-
pansion tank may be waterlogged or undersized.
Closed-type tank
logged. 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
size to be sure it is large enough for the system. If
size is too small, add additional tank(s) as neces-
sary to provide sufficient expansion. If tank size is
large enough, remove tank from system and check
charge pressure (usually 12 psig for residential ap-
plications). If tank won't hold pressure, membrane
has been damaged. Replace tank.
(continued)
3
of this manual for suggested best
— located above highest radiator or
— welded gas tight and located above
Make sure this type of tank is fitted with a
fitting
, such as the B & G Tank-Trol or Taco
Taco-Trol. This fitting reduces gravity circula-
tion of air-saturated tank water back to the
system and prevents the air from bubbling up
through the water as it returns from the sys-
tem.
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.
— welded gas tight
Systems with this type of expansion tank require
automatic air vent
at least one
cated on top of an air eliminator, as shown in
examples in manual Section
— tank is most likely water-
— first, check tank
Part number 550-110-282/1108
tank
, preferably lo-
3
.