Operating instructions

EQUIPMENT AND OPTIONAL ACCESSORIES
PROCEDURE 1—RELIEF VALVE
A relief valve must be installed on boiler. Water expands as it is heated. If there is no place for water to expand into, water pressure builds up
inside boiler and system. Should this happen, relief valve automatically opens at a predetermined pressure. This relieves strain on boiler and
system. Run a pipe from relief valve outlet (pipe must be same size as outlet, and 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.
PROCEDURE 2—EXPANSION TANK
In a properly assembled system, expanding water flows into expansion tank. This tank should be of the correct size.
The tank is filled with air. As water expands, it compresses air in 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 system.
It also prevents blowing off the relief valve.
The air in 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 system. This air would cause gurgling in pipes and inefficient circulation in radiators if left in 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 system
with new water. Fittings are provided on tank and in line to tank for bleeding off excess water or air.
When installing this tank, the following are important:
1. Tank should be higher than boiler top.
2. Pipe to tank should continuously rise up to tank (so that air can "bubble" up to it).
PROCEDURE 3—DIAPHRAGM-TYPE EXPANSION TANK
The diaphragm-type expansion tank (EX-TROL) takes the place of a conventional expansion tank. Read instructions packed with EX-TROL tank
assembly carefully.
The EX-TROL tank comes with a 10-12 psi air charge. This is same as the pressure produced in system by automatic fill valve. When system is
first filled, EX-TROL tank contains little or no water.
As water is heated, its pressure increases. It expands into EX-TROL tank compressing air in tank. This compressed air cushion permits water in
system to expand as temperature changes.
The diaphragm-type tank can be mounted on air purger fitting or at any other convenient place in supply or return line.
PROCEDURE 4—AIR-ELIMINATING FITTING (AIR PURGER)
An air purger is used to remove excess air from system. It is installed in supply line. It eliminates air from water before it reaches radiators and
bleeds off this air.
PROCEDURE 5—MAIN AIR VENT FOR DOWNFLOW SYSTEMS OR DIAPHRAGM-TYPE EXPANSION TANK
Before a system is filled with water, there is air in pipes and radiation units. Some of it will be trapped as system fills. It is possible to eliminate
most of this air through air vents on radiation units. A main air vent speeds and simplifies this process. It should be installed on highest point in
supply main when all radiation is below top of boiler.
PROCEDURE 6—AUTOMATIC FILL VALVE
For safe, efficient operation, a hot water system must be COMPLETELY FILLED with water. Adding new water when needed can be done
manually (by use of a hand valve in water supply line). This requires regular attention to system’s needs. An automatic fill valve accomplishes
this without attention. It is installed in supply line on hot water boilers only. The valve operates through water pressure differentials. It does not
require electrical connection.
PROCEDURE 7—DRAIN VALVE
This manual valve provides a means of draining all water from boiler and system. It is often installed in the 3/4-in. tapping at bottom of end boiler
section. It can also be installed in a tee where return line enters boiler.
PROCEDURE 8—WATER TEMPERATURE CONTROL
The water temperature limit control in relay is adjustable and may be set as necessary. It may be set as low as 140°F or as high as 240°F. Setting
depends on the type and amount of radiation involved and weather conditions.
PROCEDURE 9—CIRCULATING PUMP
Every forced hot water system requires a circulating pump. A separate pump or zone valve is required for each zone if there are 2 or more zones.
This pump must have capacity to provide circulation required by system. For optimum system performance, pump is connected to supply piping
AFTER expansion tank and before any zone valves. Connect pump to aquastat using 5 foot of cable supplied with boiler. The pump may also be
connected to return main.
PROCEDURE 10—VENT DAMPER
This is an automatic, motorized stack damper that has been developed to increase efficiency of heating systems by reducing standby losses from
heating apparatus and conditioned air space. The damper closes chimney vent when burner is off and fully opens it when combustion is required.
PROCEDURE 11—ROLLOUT SWITCH (FLAME ROLLOUT SAFETY SHUTOFF)
The rollout switch is a temperature-sensitive fuse link device. It is located on boiler base just outside fire box. In the event of heat exchanger
flueway blockage causing flame to roll out of fire box, the fuse blows shutting down flow of gas to main burners. The fuse does not change in
appearance when blown.
If rollout switch blows, it must be replaced with an exact replacement. Check heat exchanger flueways for blockage when restoring system to
operating condition. Do not operate system without a rollout switch.
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