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CGi
GAS-FIRED WATER BOILER — SERIES 3 —
10b
Service & maintenance – annual start-up
❏
Check/test . . .
Gas piping
1. Sniff near floor and around boiler area for any indication
gas leak
of a
Test gas piping using bubble test,
2.
manual, if there is any indication of a leak.
Cold fill and operating pressures
1. While the system is cold, note the
the boiler pressure/temperature gauge. Verify that cold fill
pressure is correct.
Watch the pressure
2.
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 separa-
tors to ensure they are operational.
2. The cap must be unscrewed one turn to allow air to escape.
3. See
Figure 34
briefly push valve
4. Replace cap
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 type. See Section
manual for suggested best location of expansion tanks and
air eliminators.
Part Number 550-142-902/1016
.
per Section
pressure reading
as the boiler and system heat up to
. If the air vent is leaking, remove cap
B
and then release to clean the valve seat.
A
by twisting all the way onto valve
Boiler Manual
Open-type
baseboard unit, usually in the attic or closet. Has a
gauge glass and overflow pipe to a drain.
Closed-type
boiler. Tank is partially filled with water, leaving an
of this
air cushion for expansion.
5
•
Make sure this type of tank is fitted with a
fitting
, such as the B & G Tank-Trol or Taco
on
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 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.
A
and
Diaphragm- or bladder-type
B
and then
with a rubber membrane to separate the tank pres-
surizing 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
cated 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 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-
4
of this
plications). If tank won't hold pressure, membrane
has been damaged. Replace tank.
— located above highest radiator or
— welded gas tight and located above
The air will escape
— welded gas tight
automatic air vent
, preferably lo-
4
.
— tank is most likely water-
— first, check tank
(cont.)
tank
47
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