Smith Cast Iron Boilers GS110W operation manual Bypass Piping

Page 16 GS110 DIRECT VENT BOILER INSTALLATION AND OPERATION INSTRUCTIONS

Ensure that the boiler is level from front to back and from side to side. Use metal shims to level the boiler. NEVER use combustible materials for shims.

Bypass Piping

CAUTION: Never connect this boiler directly to a large volume system, in-floor radiant system, snow melt system or any other system that would cause the steady state water temperature in the boiler to drop below 140°F. To prevent damage due to excessive condensation, one of the following piping options must be used or the boiler warranty will be voided!

CAUTION: The blend pump arrangement shown in Figure 16 must be used when the flow from any zone in a multiple zone system is less than 4 GPM or boiler short cycling on the high limit will occur!

For the three systems listed below, adjust the bypass valve to divert some of the heated water back into the boiler's return piping. When adjusted correctly the temperature of the boiler water will exceed 140°F within five minutes of a warm start. A plug valve should be used as the bypass valve for best system performance.

NOTE: Some of the circulator's capacity will be used in the blending process for the first two systems. Large heating systems may require a larger circulator.

System Bypass

The system bypass shown in Figure 14 should be used on single zone systems, or multiple zone systems using zone valves, when the circulator is installed in the return piping. The bypass must be installed between the supply and return pipes on the suction side of the circulator.

Pump Away Bypass

The system bypass shown in Figure 15 should be used on single zone systems, or multiple zone systems using zone valves, when the circulator is installed in the supply piping. The bypass must be installed between the supply and return pipes on the pressure side of the circulator.

Figure 15 - Pump Away Bypass Piping

Pumped Blend Bypass

The system bypass shown in Figure 16 should be used on multiple zone systems. The bypass must be installed between the supply and return pipes on the suction side of the zone circulators. The bypass valve must be installed on the pressure side of the bypass circulator.

Figure 16 - Pumped Bypass Piping

Figure 14 - System Bypass Piping