Dunkirk H2OI Single Coil Stainless Steel Indirect Water Heaters - Manual (Page 12)

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5. Pipe the relief valve discharge so that the discharge from the valve will exit only within 6 inches above, or at
any distance below, the structural floor, and cannot contact any live electrical part. The discharge opening must
not be blocked or reduced in size under any circumstances.
WARNING
Install a discharge line so that water discharged from the temperature and pressure relief valve will exit within
six (6) inches above, or any distance below, the structural floor and cannot contact any live electrical part. The
discharge line is to be installed to allow for complete drainage of both the temperature and pressure relief valve
and the discharge line. The discharge opening must not be subjected to blockage or freezing.
DO NOT thread, plug, or cap the discharge line. It is recommended that a minimum clearance of four (4) inches
be provided on the side of the water heater for servicing and maintenance of the combination temperature and
pressure relief valve.
Do not place a valve between the combination temperature and pressure relief valve and the tank!
6. Fill the water heater tank.
Open all faucets to allow air to purge from the tank and piping. Remove screens on faucets.
Open domestic hot water shut-off valve.
Open cold water inlet shut-off valve.
Purge all of the air from the domestic water system. Allow water to run so the tank is completely purged of any
debris. Run the water long enough to change at least five tank volume changes. Close all faucets. Reinstall all of
the screens in the faucets.
Check the system for leaks. Repair as required.
B. Water boiler piping. See Figures 3 and 4.
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 3, Boiler Water Piping with Zone Circulators, and Figure 4, Boiler Water Piping with Zone Valves.
2. It is recommended that 1” pipe and 1” zone valves be used on the water heater zone on residential site and 1¼"
and 1½" pipe be used on High Output units on commerical sites.
Zone Circulator System
For space heating systems that use Zone Circulators, 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
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 4. 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.