Smith Cast Iron Boilers GVIOM-5R GV100W BOILER, Installation & Operating Instructions, Fig No

Page 11

GV100W BOILER

INSTALLATION & OPERATING INSTRUCTIONS

Pumped Blend

An additional circulator can also be used to provide a return water temperature blend. This method works well with systems with multiple zones with circulators, see FIG. NO. 8. The dedicated bypass circulator provides a strong blending flow without diminishing the flow available to any heating zone. Any residentially sized circulator is adequate for this purpose.

Each of these bypass solutions also has the added benefit of increasing circulation in the boiler which will maximize tankless coil output and increase the accuracy of temperature sensing controls.

FIG NO. 9

T

T

REVERSE

AQUASTAT

SET AT 120° F

115 volts

reverse

aquastat

N.O.

circulator

24 volts

t'stat

operating aquastat

GV

N.C.

FIG. NO. 8
SUPPLY	RETURN
100%	100%
	120° F
160° F
	100%
	160° F
200%	200%
160° F	140° F
PUMPED
BYPASS

Piping For Use With Cooling Units

The boiler, when used in connection with a refrigeration system must be installed so the chilled medium is piped in parallel with the boiler. Appropriate valves must be used to prevent the chilled water from entering the boiler. See FIG. NO. 10 for the proper piping layout.

When a boiler is connected to a heating coil that may be exposed to refrigerated air from an air handling device, the piping system must be equipped with flow-control valves or some other automatic means of preventing gravity circulation of the boiler water during the cooling cycle.

FIG. NO. 10 Chiller Schematic

Reverse Acting Aquastats

An alternative for existing systems experiencing condensation that does not require re-piping the boiler utilizes a reverse acting aquastat, one that makes on temperature rise. This approach

NOTE

FOR HEATING: VALVES "H" OPEN, VALVES "C" CLOSED.

FOR COOLING: VALVES "H" CLOSED, VALVES "C" OPEN.

works best in single zone systems. Wired in series with the circulator, this control holds the circulator off until the boiler reaches an acceptable temperature and then starts system circulation, see FIG. NO. 9.

The most commonly available reverse acting aquastat is a Honeywell L4006B. The aquastat should be mounted in an immersion well directly installed in the boiler. The use of heat conductive grease (Honeywell part # 972545) in the immersion well is strongly recommended for fast and accurate temperature response. Set this adjustable aquastat to make at no less than 130° F, 54° C. While this method can cause the circulator to cycle more frequently, setting the aquastat’s differential to the maximum (25-30°F) will minimize short cycling.

EXP. TANK

RELIEF

VALVE

FILL

VALVE

DRAIN

BOILER

ROOM

UNIT

VENT

	H
PUMP	C
	DRAIN

H C

CHILLER