Brass horizontal exhaust valve high quality and low price E121 ... goes down, its down to the lower lever system, linkage, open the exhaust valve, gas leak, released the results due to ... piping and equipment system of automatic exhaust process.2,constitution Brass valve,valve cap,the float is made of high temperature ... re-install.Note:Attached blocking valve E121-Z 1/2'',Brass,caliber 1/2'' Honeywell E121 ...