Equipment And Optional Accessories; Filling Boiler - Carrier BW4 Installation, Start-Up, And Operating Instructions Manual

PROCEDURE 1—RELIEF VALVE (PROVIDED)
Each low-pressure hot water heating boiler is provided with a relief valve for over-pressure protection of boiler and heating system. The relief valve
opens when pressure in boiler rises to 30 psig. Each relief valve is provided with a lifting device for testing and should be tested monthly during
heating season. Escape piping should be provided from discharge side of relief valve so as to prevent scalding or other hazardous situations. The
escape piping must remain full size and end at a safe point of discharge.
PROCEDURE 2—EXPANSION TANK (NOT PROVIDED)
In a properly assembled system, 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 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 through it).
PROCEDURE 3—DIAPHRAGM-TYPE EXPANSION TANK (NOT PROVIDED)
The diaphragm-type expansion tank takes the place of a conventional expansion tank. Read instructions packed with tank assembly carefully.
The tank comes with a 10-12 psi air charge. This is the same as the pressure produced in system by automatic fill valve. When system is first filled,
tank contains little or no water.
As water is heated, its pressure increases. It expands into tank compressing the 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) (NOT PROVIDED)
An air purger is used to remove 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 (NOT PROVIDED)
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—AQUASTAT RELAY CONTROL (PROVIDED)
The water temperature limit control in aquastat relay is adjustable and may be set as necessary. It may be set as low as 140°F or as high as 240°F.
This depends on type and amount of radiation involved and weather conditions.
PROCEDURE 7—AUTOMATIC FILL VALVE (NOT PROVIDED)
For safe, efficient operation, a hot water system must be 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 8—DRAIN VALVE (PROVIDED)
This manual valve provides a means of draining all water from boiler and system. It is installed in a tee where return line enters boiler.
PROCEDURE 9—CIRCULATING PUMP (PROVIDED)
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 the capacity to provide circulation required by system. The pump is connected into return main just ahead of boiler. It is
also wired to electrical system.
PROCEDURE 1—HOW A HOT WATER SYSTEM OPERATES
The entire heating system (boiler, piping, and radiation units) is filled with water. As water in boiler is heated, it is pumped from top of boiler
through supply main to radiation units. The cooler water in them flows back through return main to boiler. This provides positive and rapid
response to thermostat.
PROCEDURE 2—FILLING SYSTEM WITH WATER
To fill:
1. Close air vents on all radiation units. Open valves to these units.
2. Make sure boiler and expansion tank drain cocks are closed. The air bleed screw on tank drain fitting should be closed.

EQUIPMENT AND OPTIONAL ACCESSORIES

FILLING BOILER

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