Recomended Safety Valves For the Boiler

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*BUILD YOUR OWN SAFETY VENT by Robert Warren

 I have tried various alternatives over the years, but this is the easiest as it is an off-the-shelf item. Use a brass swing-type check valve, as shown in photo 18.<  ( NOTE FROM Gilles: PHOTO SHOWS WRONG VALVE!!!!

( It actually shows a spring loaded piston type check valve, THIS WILL BE CORRECTED IN THE NEW MANUAL UNDER REVISION BY Nanda Warren AND A TEAM OF CONSULTANTS )

 

Buy a ¾ inch brass check valve of the swing type variety.

When I say swing type, this means there is no spring inside: the valve opens when water (or steam flows in one direction, and is closed when water is trying to flow from the exit side of the valve. This valve is used at the top of the 1 inch tee fitting at the top of the boiler.

< SOURCE > Charles 803 Construction Manual by The Late Robert Warren

• Any of the valves listed below will work well however we must consider the CV Factor.
  • CV Factor = Flow of water in GPM through the valve at 1 Psi Applied pressure.
• The first valve has a CV Factor of 18, meaning that 18 Gallons of water will flow through this valve in one minute.
• It would appear that the lowest cost valve is the best suited. ( WOW )
• However the stainless steel valve No: 3 has a CV Factor of 11, but a ''CRACKING'' pressure of 1.4 Psi 
  • CRACKING PRESSURE = Pressure at which the valve will start opening.
• In the intended use here, the 1.4 Psi may be welcome, without any modifications to the valve.

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1 ) Bronze Swing Check Valves
	• Maximum Pressure: 200 psi @ 150° F;   Steam: 125 psi @ 406° F • Cracking Pressure: Less than 0.5 psi • Temperature Range: -20° to +406° F CV Factor: 3/4 Inch    = 18 1 Inch       = 31 1 1/4 Inch = 54 1 1/2 Inch  =76 2 Inch     = 131

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