Dunkirk H2OI Stainless Steel Dual Coil Solar Water Heaters - Manual (Page 10)

10
B. Water boiler piping. See Figures 2 and 3.
1. Determine where the boiler, the space heating, and the water heater connections should be made based on the
type of piping system that is either in place, or is to be installed for a new hydronic system installation. See
Figure 2, Boiler Water Piping with Zone Circulators, and Figure 3, Boiler Water Piping with Zone Valves.
2. It is recommended that 1” pipe and 1” zone valves be used on the water heater zone.
Zone Circulator System
For space heating systems that use Zone Circulators, refer to Figure 2. The water heater connection labeled
“BOILER SUPPLY” should be piped to the boiler supply piping after the air purger and before the space heating
takeoffs. Mount the water heater circulator as close as possible to the water heater, and make sure the flow
arrow points toward the water heater. The use of shut-off valves is recommended for future service convenience.
The water heater connection labeled “BOILER RETURN” should be piped to the boiler return piping as close to
the boiler as possible and after any flow control or check valves in the space heating return piping. The use of a
union and a shut-off valve is recommended. The use of a check valve is required to prevent back flow through
the water heater during operation of the space heating system.
Zone Valve System
For a space heating system that uses Zone Valves, refer to Figure 3. The water heater connection labeled
“BOILER SUPPLY” should be piped to the boiler supply piping after the air purger and before the space heating
circulator. Mount the water heater circulator as close as possible to the water heater, and make sure the
flow arrow points toward the water heater. The use of a shut-off valve is recommended for future service
convenience.
The water heater connection labeled “BOILER RETURN” should be piped to the boiler return piping as close to
the boiler as possible and after any flow control or check valves in the space heating return piping. The use of a
union and a shut-off valve is recommended. The use of a check valve is required to prevent back flow through
the water heater during operation of the space heating system.
Thermal expansion tank – Optional
Required if cold water line is equipped with a backflow preventer or pressure reducing valve.
Water hammer arrester – Optional
Dishwashers, clothes washers, and fast-closing positive shutoff valves incorporated in the system all
contribute to creating water hammer. Install a water hammer arrester to prevent damage to pipes and appliances. See
control manufacturer's instructions for application and installation.
unions
Use dielectric unions or couplings to protect hot and cold water fittings from corrosion when connecting dissimilar
materials such as copper and galvanized pipe.
Backflow preventer – Optional
Required for Commonwealth of Massachusetts
Vacuum breaker – Optional
Required for Commonwealth of Massachusetts