ensuring the static pressure is correctly maintained for the pressure switch to close during the pre-purge cycle

and ICP units

For unconditioned or outdoor environments

For any technician dealing with high-efficiency boiler installs or retrofitting older tanks

As the official replacement for S8402-093

Johnson Controls A-4000-144 Relief Valve Els PW 17895 ensuring the static pressure isThe Johnson Controls A 4000 144 is a professional grade safety relief valve designed specifically for pneumatic control systems and air compressor accessories. Featuring a 1 4" NPT male connection, this pop type valve is factory set to activate at 25 PSIG, providing a critical mechanical failsafe against overpressurization in the supply line. The robust brass body construction ensures durability and corrosion resistance, essential for maintaining the