Weil-McLain 105, 80, 230, 310, 155 manual Chilled water systems, Chilled water system plus optional

3 GAS-FIRED WATER BOILER — Boiler Manual

Install water piping (continued)

Chilled water systems		Figure 10 Chilled water system plus optional
1. Install boiler so that chilled medium is piped in parallel with the heating		DHW piping
boiler. Use appropriate valves to prevent chilled medium from entering
boiler. See Figure 10 for typical installation of balancing valve and check
valve.
2. The space heating system may be zoned with circulators if a separate
circulator is supplied for the chilled water loop.
3. If boiler is connected to heating coils located in air handling units where
they can be exposed to refrigerated air, use flow control valves or other
automatic means to prevent gravity circulation during cooling cycle.
	Follow these piping guidelines below to ensure chilled water
	does not enter the boiler loop.
	Chilled medium, if used, is piped in parallel with heating boiler
	as shown in Figure 10. Use appropriate valves to prevent chilled
	medium from entering boiler.
	If boiler is connected to heating coils located in air handling
	units where they can be exposed to refrigerated air, use flow
	control valves or other automatic means to prevent gravity
	circulation during cooling cycle.
NOTE 1: To ensure adequate flow rate through the boiler, use the following
pipe size on all boiler loop piping (connecting boiler to and from
the primary/secondary connection, item 21):
Ultra-80 or Ultra-105 – 1" or larger.
Ultra-155 or -230 – 1¼" or larger.
Ultra-310 – 1½" or larger.
	Use at least the minimum piping size above and pipe the boiler
	using only primary/secondary piping as shown. Failure to
	follow these guidelines could result in system problems.

Legend		Figure 10
1	Ultra boiler		12	Boiler circulator
2	Indirect water heater (DHW), if used		13	Zone valves, typical
3	Boiler relief valve (see page 12 for piping details)		15	Closed-type expansion tank
4	Relief valve discharge piping (see page 12 for details)		16	Water chiller
5	DHW circulator (see page 14 for suggested sizing)		17	Check valve
6	Isolation valves		18	Strainer
7	System circulator		19	Balancing valve
9	Air separator (DO NOT use automatic air vents on systems fitted with closed-		20	Make-up water supply
	type tanks)		21	Primary/secondary connection

10Flow/check valves (with weighted seats to prevent gravity circulation)

11Purge/drain valves

18 Part number 550-101-233/0903