Be sure valve, regulator or part being replaced matches old part. IMPORTANT: Always use a good thread sealant on threads before installing new part (on flare fittings no sealant required). L.P. sealer should be used on all liquid propane fittings. Do not strip thread by over tightening. After parts are installed check for leaks with soapy water on ALL connections with gas pressure on. Re-tighten if bubbles appear – NEVER do this test with an open flame.