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RELIEF VALVE
You must have a relief valve on your boiler. Water expands
as it is heated. If there is no place for the water to expand
into, water pressure will build up inside the boiler and system.
Should this happen, the relief valve will automatically open
at a pre-determined
pressure. This wi(I relieve the strain on
the boiler and system. Run a pipe from the relief valve outlet
(pipe must be same size as outlet and the open end must
not be threaded} to an open drain, tub or sink, or other suitable
drainage point not subject to freezing. Failure to do so may
cause water damage or injury should relief valve release.
EXPANSION
TANK
In a properly assembled system, the expanding water flows
into an expansion tank. This tank should be of the correct
size.
The tank is filled with air. As the water expands it compresses
the air in the tank to form an air pressure cushion. This "spring-
like" cushion serves to maintain correct operating
water
pressure regardless of water temperature. This assures a
"full measure"
of water, even in the highest radiation unit
of the system. It also prevents blowing off of the relief valve.
The air in the tank in the beginning
(with system filled with
cold water) is sufficient for proper operation. The tank also
serves as a trap for excess air in the system. The air would
cause gurgling in the pipes and inefficient circulation in the
radiators if left in the system.
It is possible for a tank to become "water-logged"
(filled with
water). It can also become overfilled with air. This can happen
after filling the system with new water. Fittings provided on
the tank and in the line to the tank are for bleeding off excess
water or air.
When installing this tank, it is important: 1} That the tank be
higher than the boiler top. 2) That the pipe to the tank
continuously rises up to the tank (so that air can "bubble"
up to it).
DIAPHRAGM TYPE EXPANSION TANK
The diaphragm
type expansion tank (EX-TROL} takes the
place of the conventional expansion tank. Carefully read the
instructions packed with your EX-TROL tank assembly
The EX-TROL tank comes to you with a 10-12 pounds per
square inch air charge. This is the same as the pressure
produced
in the system by the automatic fill valve. When
the system is first filled, the EX-TROL tank will contain little
or no water.
As the water is heated its pressure increases. It expands
into the EX-TROL tank, compressing
the air in the tank. This
compressed
air cushion permits the water in the system to
expand as the temperature changes.
The diaphragm type tank can be mounted on the air purger
fitting or at any other convenient place in the supply or return
line.
AIR ELIMINATING
FITTING
(AIR PURGER)
An air purger is used to remove excess air from the system.
It is installed in the supply line. It will eliminate air from the
water before it reaches the radiators and bleed off this air.
MAIN AIR VENT FOR DOWN FLOW SYSTEMS OR
DIAPHRAGM TYPE EXPANSION TANK
Before a system is filled with water, there is air in the pipes
and radiation units. Some of it will be trapped as the system
is filled. It is possible to eliminate most of this air through
the air vents on the radiation units. A main air vent will speed
and simplify this. It should be installed on the highest point
in the supply main when all radiation is below top of boiler.
AUTOMATIC FILL VALVE
For safe, efficient operation, a hot water system must be
completely
tilled
with water. Adding
new water, when
needed can be done manually (by use of a hand valve in
the water supply line}. This requires regular attention to the
system's needs. An automatic fill valve accomplishes
this
without attention. It is installed in the supply line on hot water
boilers only The valve operates through
water pressure
differentials. It does not require an electrical connection.
DRAIN VALVE
This manual valve provides a means of draining all water
from the boiler and system. It is often installed in the 3A,
tapping at the bottom of the end boiler section. Or it can
be installed in a tee where the return line enters the boiler.
WATER TEMPERATURECONTROL
The water temperature limit control in the relay is adjustable
and may be set as necessary. It may be set as low as 140 °
E, or as high as 240 ° E This depends on the type and amount
of radiation involved and weather conditions.
CIRCULATING PUMP
Every forced hot-water system requires a circulating
pump.
A separate pump or zone valve is required for each zone,
if you have a two or more zone system. This pump must
have the capacity to provide the circulation required by your
system. The pump is connected
into the return main just
ahead of the boiler. It is also wired to the electrical system.
VENT DAMPER
This product is an automatic, motorized stack damper that
has been developed
to increase the efficiency of heating
systems by reducing
standby
losses from the heating
apparatus and the conditioned air space. The damper closes
the chimney vent when the burner is off and fully opens
it when combustion is required.
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