Dunkirk DWB Series - Manual (Page 12)

12
H. Extended DHW calls resulting in delayed response
to CH calls.
WARNING
Burn and Scald Hazard. Safety relief vlave
could discharge steam or hot water during
operation. Install discharge piping per these
instructions. Failure to do so could result in
death or serious injury.
!
5.5 Safety Relief Valve
NOTICE
Boiler rated at 43.5 psig (.30MPa) maximum allowable
working pressure. Boiler provided with 30 psig
(.21MPa) safety relief valve.
• Install safety relief valve using pipe fi ttings provided with
boiler. See fi gure 8.
• Install safety relief valve with spindle in vertical position.
• Do not install shutoff valve between boiler and safety
relief valve.
• Install discharge piping from safety relief valve. See
fi gure 9.
• Use ¾” or larger pipe.
• Use pipe suitable for temperatures of 375°F (191°C)
or greater.
• Individual boiler discharge piping shall be independent
of other discharge piping.
Figure 7 - Indirect Tank Performance Chart
• System piping connected to heating coils located in air
handling unit exposed to refrigerated air circulation. Install
fl ow control valves or other automatic means to prevent
gravity circulation of boiler water during cooling cycle.
5.4 Storage Tank Connection For Domestic Hot
Water Production
• Unit’s electronic board is arranged for managing an
external storage tank for domestic hot water production.
• See fi gure 10 for hydronic plumbing.
• Make electrical connections as shown on wiring diagram
page 36.
• Boiler’s control system recognizes presence of hot water
tank probe and automatically confi gures DHW function,
activating display and controls.
• Match Indirect tank heat exchanger and boiler capacity.
• Indirect tank requires dedicated pump. See fi gure 7 and
indirect tank specifi cation to determine pump.
• Incorrect tank size or insuffi cient fl ow may result in:
F. Unsatisfactory indirect tank performance.
G. Boiler short cycling
5 - HYDRONIC PIPING
Figure 8 - Safety Relief Valve & Air Vent
(Viewed from front of boiler)
1” MPT
Coupling 1” NPT
Nipple 1” x 5”
Tee 1” x 1” x ¾”
Safety Relief
Valve
Street Elbow ¾”