Dunkirk WPSB Series II - Manual (Page 25)

25
EQUIPMENT AND OPTIONAL ACCESSORIES
WARNING
Burn and scald hazard. Safety relief valve could
discharge steam or hot water during operation.
Install discharge piping per these instructions.
!
SAFETY RELIEF VALVE
Safety relief valve is required on your boiler. Water expands
as it is heated. If there is no place for water to expand
into, water pressure will build up inside boiler and system.
Should this happen, safety relief valve will automatically
open at predetermined pressure. This will relieve the strain
on boiler and system. Run pipe from relief valve outlet
(pipe must be same size as outlet and open end must not
be threaded) to 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 safety relief valve
release.
EXPANSION TANK
Expanding water fl ows into expansion tank. Tank should
be correct size. Tank is fi lled with air. As water expands it
compresses air in the tank to form air pressure cushion.
This “spring-like” cushion serves to maintain correct
operating water pressure regardless of water temperature.
This assures “full measure” of water, even in highest
radiation unit of system. It also prevents blowing off of
safety relief valve. Air in tank in beginning (with system
fi lled with cold water) is suffi cient for proper operation.
Tank also serves as trap for excess air in system. Air
would cause gurgling in pipes and in effi cient circulation in
radiators if left in system.
It is possible for tank to become “waterlogged” (fi lled with
water). It can also become overfi lled with air. This can hap-
pen after fi lling system with new water. Fittings provided on
tank and in line to tank are for bleeding off excess water or
air.
When installing this tank, it is important:
1. Tank be higher than boiler top.
2. Pipe to tank continuously rises up to tank (so air
can “bubble” up to it).
DIAPHRAGM TYPE EXPANSION TANK
Diaphragm type expansion tank takes place of conventional
expansion tank. Carefully read instructions packed with
your tank assembly.
Tank comes with 10-12 pounds per square inch air charge.
This is the same as pressure produced in system by automat-
ic fi ll valve. When system is fi rst fi lled, tank will contain little
or no water.
As water is heated its pressure increases. It expands into
tank, compressing air in tank. Compressed air cushion per-
mits water in system to expand as temperature changes.
Diaphragm type tank can be mounted on air purger fi tting
or at any convenient place in supply or return line.
AIR ELIMINATING FITTING (AIR PURGER)
Air purger is used to remove excess air from system. It
is installed in supply line. It will eliminate air from water
before it reaches radiators and bleed off this air.
MAIN AIR VENT FOR DOWN FLOW SYSTEMS OR
DIAPHRAGM TYPE EXPANSION TANK
Before system is fi lled with water, there is air in pipes and
radiation units. Some of it will be trapped as system is
fi lled . It is possible to eliminate most of this air through
air vent on radiation units. Main air vent will speed and
simplify this. Install on highest point in supply main when
all radiation is below top of boiler.
AUTOMATIC FILL VALVE
For a safe, effi cient operation, hot water system must be
completely fi lled with water. Adding new water, when
needed can be done manually (by use of hand valve in
water supply line). Requires regular attention to system’s
needs. Automatic fi ll valve accomplishes this without atten-
tion. Install in supply line on hot water boilers only. Valve
operates through water pressure differentials. It does not
require electrical connection.
DRAIN VALVE
Manual valve provides means of draining all water from
boiler and system. It is often installed in 3/4” tapping at
bottom of end boiler section. Or it can be installed in tee
where return line enters boiler.
CIRCULATING PUMP
Every forced hot-water system requires circulating pump.
Separate pump or zone valve is required for each zone,
if you have a two or more zone system. Pump must have
capacity to provide circulation required by your system.
Pump is connected into main just ahead of boiler. It is also
wired to electrical system.
VENT DAMPER
This product is automatic, motorized stack damper
developed to increase effi ciency of heating system by
reducing standby losses from heating apparatus and
conditioned air space. Damper closes chimney vent
when burner is off and fully opens it when combustion is
required.