Propane was leaking between tank and regulator on my BBQ. Replaced with three new regulators and two new propane tanks but still get strong hissing from vent hole and strong smell of propane when I open the tank valve

James,

Try Reseting the Regulator.....

1. Turn off the gas at the propane tank.
2. Disconnect the hose from the propane tank.
3. Open the lid of your BBQ Grill.
4. Turn all the burner valves to high.
5. Wait for 2 minutes.
6. Turn off all the burner valves.
7. Connect the gas line back up to the propane tank.
8. Turn on the propane tank slowly.
9. Light the grill using the proper ignition sequence.

Best to you.

HAVE YOU TRIED BLEEDING THE AIR OUT OF THE GAS LINE

I've been in the propane business 28 years and have found regulators from the 1950's still in use today. Regulator manufacturers tell us they should be replaced after 25 years. It should typically outlast the grill itself, which often require new burners, cooking grids, etc. The hissing sound can just be the flow of gas thru the regulator. If you smell gas however, then you should replace it. If it is affecting the pressure to the burners and not getting hot enough to cook properly, then replace it as well.

It does sound like a faulty regulator, propane operates at 2.75kpa and if the existing regulator is for natural gas it is only 1.1kpa.
If you are operating off a bulk tank the regulator on the tank may be high pressure then the secondary regulator on the appliance may be to bring it down further. See if you can get a manometer and check it all out before doing any regulator removing.

the problem is going to be the QCC handwheel or it is the o-ring in the tank. if you're swapping tanks instead of refilling, get a new tank but before attaching it turn the bbq on without a tank attached. leave it on for a few minutes so any residual pressure dissipates into the atmosphere. turn everything off, attach the regulator and turn the tank on very slowly before lighting the grill. the QCC handwheel can be problematic although it is rare. You can replace it with the older style POL connection which is a more reliable connection for the LP cylinder. Simply trace the gas line from the regulator to the manifold and unscrew it. the connection is a 3/8" flare which means you do not need putty or tape, just replace the gas hose and regulator as tight as possible. pressurize the line and pour soapy water on it to make sure it is not leaking.

It could be a defective LP gas regulator or a restriction somewhere in the gas line for the bbq. This can also happen if the propane tank is overfilled.

First make sure that the LP tank is not overfilled. If you open the bleeder hole on the tank(small screw next to the valve) there should be no liquids coming out. If liquid propane is coming out then the tank is overfilled. Keep the bleeder screw loose until the liquid disappears then tighten. Re-connect the tank and see if that fixes the problem.

Then inspect all the gas lines on the bbq. Make sure that there are no kinks or crushed lines.

Then take a look at the gas regulator. Try turning on all the burners then give the regulator a couple good taps on the housing with something solid. See if the burner changes size. If it does and then goes back down it could be the gas regulator. Also take a look at the regulator housing. There should be a very small hole on the housing and it might be labled "vent". Make sure that this little hole is not plugged with any debris or that can cause a low pressure problem. You can use a sewing needle to gently poke out the hole. You will know if it worked because the burners will become much higher. And you could also try disconnecting the hose and regulator assembly from the bbq then turn on the LP tank slowly with the regulator connected. You should get plenty of gas flow from the end of the hose. Then use your hand to block and release the flow a couple times to try and clear any debris that might stuck in the regulator.BE VERY CAREFUL DOING THIS!!! MAKE SURE YOU ARE CLEAR OF ANY SOURCES OF IGNITION BEFORE TRYING TO CLEAR THE REGULATOR. Then reconnect the hose regulator and tank to see if the problem is fixed. If you are getting very low flow from the hose with the regulator disconnected then it is probably a defective regulator. They are pretty standard and you can purchase a new LP hose and regulator assembly from most home improvement stores.

If the regulator checks out good then I would think that there is a restriction in the main gas line for the bbq after the regulator. You will need you dis-assemble the main line and blow it out with some compressed air to clear the restriction.

the regulator could have gone into lock up.
try this to unlock it...

1. Open the BBQ Lid
2. Turn ALL main control knobs to the "OFF"/CLOSED position
3. Turn the Propane tank valve to the "OFF"/CLOSED position
4. Disconnect the Regulator hose from the Propane tank
5. Turn ALL main control knobs to the "ON"/OPEN position
6. Let stand for 1-2 minutes, allowing all excess gas in valves and manifold to dissipate
7. Turn ALL control knob back to the "OFF"/CLOSED position
8. Reconnect the regulator hose to the Propane tank- hand tighten only.
9. Check all hose connections to ensure that a positive seal has been made
10. SLOWLY turn "ON"/OPEN the propane gas supply
11. Wait approximately 5 seconds for the regulator pressure to stabilize
12. Turn "ON"/OPEN the selected burner control knob to "HI"
13. Press the Multi Spark ignition button or match light selected burner.
14. Hope this helps you has me in the past!

The new style OPD valves have a small brass ring located in the female fitting on the LP tank. Over time this ring can work loose and then it does not allow the male fitting to fully depress the OPD valve thus reducing your gas flow
Using a small flat bladed screw driver tighten the small brass ring This should solve your problem
IF not you might want to remove the cap (white) on your regulator and try slowly adjusting the regulator, make small adjustments and try the BBQ My Weber if I set the front and back burners to MED I get right at 350 degrees in 60 degree outdoor temps. Adjusting the regulator will take some time to get it right but If it is not your tank it is most likely your regulator out of adjustment

Sounds like you may have a bad regulator, try replacing it.

I switched to the new style 20# tank with the new turn-on knob.  I couldn't get enough gas pressure to the BBQ burners for all three burners to light or to keep a strong flame on even one burner.  The new style tanks have a safety valve on the inside of the tank that shuts the gas off if you turn the knob on too fast because the safety valve thinks there is leak.  Shut everything off and then try turning the knob on real slow, especially at first, before turning it all the way on.  If that doesn't work (it didn't for me), then replace the large plastic connection valve knob (female end) that attaches the regulator to the tank.  Mine was for the old style tank and was black (low pressure).  I went to a propane company and had them replace it with a green knob (higher pressure).  Took it home and WALA!  Everything works fine now.  But it was very frustrating trying to figure why I couldn't get any gas to the burners after buying a brand new tank.  I hope this helps solve your problems.