Valve Proof of Closure on Select RM7800's

Large commercial burners, depending on local codes, may require 2 safety shut off valves with a normally open vent valve between them to remove any ‘leakage’ of gas from the building should there be a failure in the safety shut off valves.  This is often referred to as a Double Block and Bleed system.  This system has worked relatively well for decades, however there are some inherent problems with this:

-          There is normally no mechanism that alerts to a failure in the NO vent valve.

-          The normally open solenoid valve typically fails in the open position, which means that gas is vented to atmosphere whenever there is a call for heat.  This reduces burner efficiency greatly, and also has a negative impact on the environment.  Often these failures an go undetected for a long time.

-          When there is a leak in one of  the safety shut off valves, (SSOV), there is no alert mechanism to have the problem fixed.

-          It is often difficult and expensive to run the vent line from the burner equipment to the atmosphere

As a solution, Honeywell now offers a safer alternative to this on selected RM7800 family relay modules.  The Honeywell Valve Proving System, (VPS), eliminates the need for the NO vent valve.  Instead, a pressure switch is located between the SSOVs.  The RM7800 relay module cycles the valves, and the pressure switch is able to determine if either of the SSOV’s is leaking.  Any evidence of leaking or valve failure would cause a safety lockout.

The Honeywell VPS is a safer, more reliable and cost efficient way to manage gas trains on commercial burners.