Lifebreath 4TONVENTAC Combo System Basic Principles, Closed/Open Combo System, Closed Loop System

Combo System Basic Principles

Closed/Open Combo System

From the aspect of delivery of domestic hot water and space heating, the Open and Closed systems operate the same. A system becomes closed when a backflow prevention valve or check valve is installed in the cold water piping upstream of the water heater. A backflow prevention valve will prevent the pressure created when water is heated in the water heater, from being relieved into the cold water system.

Therefore, an expansion tank (or equivalent device) may be installed as part of any closed system. The operations of the valve and expansion tank are discussed later in this section of this manual.

Note: Water systems that incorporate a pressure tank (well systems) are normally open systems.

COLD WATER INLET	DOMESTIC HOT WATER
CHECK
VALVE
VALVE
(shut off)	ANTI-SCALD VALVE	SUPPLY AIR	COOLING COIL	SCHEMATIC SYSTEM
	(WHEN REQUIRED)		(OPTIONAL)
EXPANSION TANK		VALVE		DIAGRAM
(WHEN REQUIRED)
OR OTHER MEANS		(shut off)
			RETURN AIR	(Closed Loop System)
	VALVE	VALVE
	(shut off)	(balancing)
		CHECK
	WATER HEATER	VALVE
		HEATING COIL
		HRV/ERV CORE
		DRAIN
		VALVE
		BLOWER

SCHEMATIC SYSTEM DIAGRAM (Open System)

Note:

Plumbing components and system configuration may vary from diagram portrayed. Refer to local codes, local bylaws and installation manuals supplied with water heater before starting any installation work.

COLD WATER INLET	DOMESTIC HOT WATER
VALVE
(shut off)	ANTI-SCALD VALVE	SUPPLY AIR	COOLING COIL
			(OPTIONAL)
	(WHEN REQUIRED)
	VALVE
	(shut off)
			RETURN AIR
	VALVE	VALVE
	(shut off)	(balancing)
		CHECK
	WATER HEATER	VALVE
		HEATING COIL
		HRV/ERV CORE
		DRAIN
		VALVE
		BLOWER
	5