Install Instructions

Part Number 550-142-902/1016
CGi
GAS-FIRED WATER BOILER — SERIES 3 — Boiler Manual
47
10b
Service & maintenance – annual start-up (cont.)
❏ Check/test . . .
Gas piping
1. Sniffnearoorandaroundboilerareaforanyindication
of a gas leak.
2.
Test gas piping using bubble test,perSection5 of this
manual, if there is any indication of a leak.
Cold fill and operating pressures
1. While the system is cold, note the pressure reading on
theboilerpressure/temperaturegauge.Verifythatcoldll
pressure is correct.
2.
Watch the pressure as the boiler and system heat up to
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. If the air vent is leaking, remove cap A and
briefly push valve B and then release to clean the valve seat.
4. Replace cap
A by twisting all the way onto valve B and 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type.SeeSection4 of this
manual for suggested best 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ttedwitha
tank
tting
,such as the B & GTank-Trol or Ta co
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.
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 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
automatic air vent, preferably lo-
cated on top of an air eliminator, as shown in
examplesinmanualSection
4.
2. If relief valve has tended to weep frequently, the
expansion tank may be waterlogged or undersized.
Closed-type tank — tank is most likely water-
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 — first, check tank
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.