Operating instructions
13
5.1 General
•  Install piping in accordance with authority having jurisdiction.
NOTICE
Use two (2) wrenches when tightening and tting 
to pipe boiler's threaded ttings. Boiler's internal 
piping can be damaged if subjected to excessive 
torque.
•  Support system piping and safety relief valve discharge  
piping. Boiler's internal piping and wall mount bracket can 
be damaged if subjected to excessive weight.
•  Size central heating pump (and domestic hot water 
pump, if used) for system requirements only. Internal 
heat exchanger pump compensates for pressure drop 
through boiler internal piping and heat exchanger.
•  Thoroughly clean and ush system before connecting to 
boiler.
•  If oil is present in system water, use approved detergent to 
wash system.
•  Flush system to remove any solid objects such as metal 
chips, bers, or Teon tape, etc.
5.2 Special Conditions
• System piping exposed to freezing conditions: Use 
inhibited proplyene glycol solutions certied by uid 
manufacturer for use with closed water heating system.  
Do not use automotive or ethylene glycol.
• Boiler installed above radiation level (or as required by 
authority having jurisdiction). Integral low water cutoff 
provided in boiler. See pages 9 & 10. 
• Boiler used in connection with refrigeration system. 
Install piping in parallel with boiler, with appropriate 
valves to prevent chilled medium from entering boiler.
•  System piping connected to heating coils located in air 
handling unit exposed to refrigerated air circulation. Install 
ow control valves or other automatic means to prevent 
gravity circulation of boiler water during cooling cycle.
5.3 Safety Relief Valve and Air Vent
NOTICE
Boiler rated at 150 psig (1.03 MPa) maximum 
allowable working pressure. Boiler provided with 30 
psig (206 kPa) safety relief valve. Field source safety 
relief valve for system pressures greater than 25 psig. 
Temperature Pressure Gauge satisfactory for 60 psig 
operation. Field source temperature pressure gauge 
for system pressures greater than 60 psig.
• Install safety relief valve and air vent using pipe ttings 
provided with boiler. See gure 5-1
• Install safety relief valve with spindle in vertical position.
• Do not install shutoff valve between boiler and safety 
relief valve.
WARNING
• Poison hazard. Ethylene glycol is toxic. Do not 
use ethylene glycol.
• Never use automotive or standard glycol antifreeze, 
even ethylene glycol made for hydronic systems.
• Ethylene glycol can attack gaskets and seals used 
in hydronic systems.
• Use only inhibited proplyene glycol solutions  
certied by uid manufacturer as acceptable for 
use with closed water heating system.
• Thoroughly clean and ush any system that used 
glycol before installing new Boiler.
• Provide user with Material Safety Data Sheet 
(MSDS) on uid used.
! 
NOTICE
Do not expose boiler and condensate piping to 
freezing temperatures. 
FIGURE 5-1 Safety Relief Valve & Air Vent (Viewed 
from front of boiler)
Safety Relief 
Valve
3/4" NPT 
Nipple
3/4" x 1/4" NPT 
90° Elbow
3/4"F x 3/4"M 
NPT Tee
 3/4 NPT
Air Vent
Position Air Vent and Safety Relief Valve 
to provide space for discharge piping.
5 - HYDRONIC PIPING










