Hydronic Piping; Special Conditions; Safety Relief Valve And Air Vent; Bushing ¾" X ¼" - HELIX VX-399 Installation, Operation & Maintanance Manual

5.1 General
• Install piping in accordance with authority having
jurisdiction.
NOTICE
Use two (2) wrenches when tightening boiler's
fitting and pipes. 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 can be damaged if subjected
to excessive weight.
• Size central heating pump (and domestic hot water pump,
if used) for system requirements only.
• Thoroughly clean and flush 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, fibers, or Teflon tape, etc.

5.2 Special Conditions

• System piping exposed to freezing conditions: Use
inhibited propylene glycol solutions certified by fluid
manufacturer for use with closed water heating system.
Do not use automotive or ethylene glycol.
• 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 flow control valves or other automatic means to
prevent gravity circulation of boiler water during cooling
cycle.
5.3 Safety Relief Valve
NOTICE
Boiler rated at 150 psig (1.03 MPa) maximum
allowable working pressure. Boiler provided with 50
psig (345 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. See figure 5-1
• 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
figure 5-2.
• Use ¾" or larger pipe.

5 - HYDRONIC PIPING

• 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 propylene glycol solutions
certified by fluid manufacturer as acceptable for
use with closed water heating system.
• Thoroughly clean and flush any system that used
glycol before installing new Boiler.
• Provide user with Material Safety Data Sheet
(MSDS) on fluid used.
Do not expose boiler and condensate piping to
freezing temperatures.
FIGURE 5-1 Safety Relief Valve (Viewed from top, left
side of boiler)
* Optional Aquastat Limit Control
*Tee 1¼" x 1¼" x ¾"
* 1¼"Close Nipple
Safety Relief
Valve
Elbow ¾" 90°
1¼" Close Nipple
Bushing 1¼" x ¾"
Controls Tree
* Included in optional accessory kit.
11
!
WARNING
NOTICE
*Limit Well ½"
1¼" Close Nipple
Position Safety Relief Valve to provide
space for discharge piping.
P/N 240010943, Rev. C [09/07/2016]
Temperature
Pressure
Gauge
Bushing
¾" x ¼"
Bushing
1¼" x ¾"