National Products BW3 Installationðsystem Piping, Procedure 1ÐFOR USE with Cooling Units

INSTALLATIONÐSYSTEM PIPING

1.Place boiler in selected location (as close to chimney as possible). Boiler is shipped assembled. Only the relief valve with a drain line to carry any water to a drain and a drain valve need to be installed.

2.Install relief valve on 3/4-in. pipe nipple in tapped opening in left end section. Connect a drain line of same pipe size (3/4 in.) to carry any water away to a drain. No shutoff of any description shall be placed between safety relief valve and boiler, or on discharge pipes between such safety valves and the atmosphere. Installation of safety relief valve shall conform to the requirements of the ANSI/ASME Boiler and Pressure Vessel Code, Section IV.

3.Install drain valve on lower left side of boiler as marked.

4.Connect supply and return lines to boiler. The connections may require certain additional fittings and parts. (See Fig. 2 and 4.)

ELECTRIC

ZONE

VALVES

AIR VENT
COLD WATER		COLD
INLET
RELIEF	SUPPLY	WATER
		INLET
	MAIN
VALVE
		RELIEF
	AIR	VALVE
	PURGER
GAUGE		GAUGE
		TO ZONE
	FILTROL	2 SUPPLY
		MAIN
	TANK
	LIMIT
RETURN	CONTROL
LINE

TO ZONE 1

SUPPLY MAIN

AIR VENT

AIR PURGER

FILTROL

TANK

LIMIT

RETURN CONTROL LINE

A95176	A96140
Fig. 2ÐForced Hot Water Typical Piping	Fig. 3ÐForced Hot Water Typical Piping with
	Zone Control Valves

If installing an entire new heating system, first install all radiation units (panels, radiators, or cabinets) and supply and return mains, then make connections at boiler.

In connecting cold water supply to water valve, make sure that a clean water supply is available. When water supply is from a well or pump, a sand strainer should be installed at pump.

A hot water boiler installed above radiation level must be equipped with a low water cut-off device. A periodic inspection is necessary as is flushing of float-type devices per the manufacturer's specific instructions.

PROCEDURE 1ÐFOR USE WITH COOLING UNITS

When this boiler is used in connection with refrigeration systems, it shall be installed so that the chilled medium is piped in parallel with the heating boiler. Appropriate valves must be used to prevent the chilled medium from entering the heating boiler. (See Fig. 4.)

When this boiler is connected to heating coils located in air handling units where they may be exposed to refrigerated air circulation, the piping system shall be equipped with flow control valves or other automatic means to prevent gravity circulation of boiler water during cooling cycles.

PROCEDURE 2ÐLOW DESIGN WATER TEMPERATURE SYSTEMS (BELOW 140°F)

If boiler is to be used in a heating system where design water temperatures below 140°F are desired (for example radiant floor heating), a 3-way or 4-way mixing valve or suitable alternative is required to prevent low temperature return water from entering boiler. Follow mixing valve manufacturer's Installation Instructions.

The minimum design return water temperature to boiler to prevent condensation in boiler and venting system is 120°F. The minimum high limit setting is 140°F.

CHIMNEY AND VENT PIPE CONNECTION

For boilers with connections to gas vents or chimneys, vent installations shall be in accordance with Part 7 NFGC, Venting of Equipment, in the United States or Part 7 NSCNGPIC, Venting System and Air Supply for Appliances in Canada, and applicable provisions of local building codes.

PROCEDURE 1ÐCHECKING CHIMNEY

The chimney is a very important part of the heating system. It must be clean, the right size, properly constructed, and in GOOD CONDITION. No boiler can function properly with a bad chimney.

1.Use local codes for installation or NFGC. In Canada, follow CAN/CGA-B149.1 or .2 Installation Codes. It is very important to properly size the venting system for induced draft appliances. Consult the Vent Sizing Tables in Part 11 of the NFGC in the United States for correct sizing information. In Canada, consult the Vent Sizing Tables in Appendix B of the NSCNGPIC.

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