Gotcha of the Day: New Propane Tank Doesn't Work with Weber Grill

Usually my gotchas are software related, this one however, isn't. It's all about hardware.

Yesterday, I went out replaced the two propane cylinder I have for our Weber Spirit Grill. I've done this many times, and the hardest part is usually finding a store with propane in stock. I got my two canisters home and ran into the following odd sequence:

1. I plugged in cylinder A to the grill. Turned on the grill. No gas appeared to come out (no sound or smell). I attempted to light the grill, nothing happened.
2. I removed A, and plugged in cylinder B. The gas turned on as I expected. I was able to light the grill.
3. Cylinder A had no obvious defects, so I removed B and plugged A back in. It didn't work. It was heavy enough that I could be sure it had gas in it, but none appeared to be released when the grill was on.
4. At this point, I figure A was a dud cylinder. I plugged B in. To my surprise, it no longer worked.
5. I swapped them both one more time confirming that A definitely didn't work. When I put B in place again, it did work.
6. While I was confused why B was working, then stopped, then started again, I pretty much left the situation alone and focused on the import task of cooking dinner.

Not sure what else to do, I dropped a note to support@weberstephen.com describing the above situation and asking for suggestions. Did I just get a bad cylinder? Was my grill broke? What did I need to buy? (Probably a new grill, and while I'm at it, a new deck to put it on.)

To my surprise, a couple of hours later I got the following note back:

[...pleasantries trimmed..]

It sounds like you may be activating a safety device built into the regulator. This safety device is a component of all LP gas regulators and is designed to reduce the flow of gas in the event of a leak.

You can inadvertently activate the safety device without having a gas leak. Typically, this occurs if you do not wait a sufficient time between opening the tank valve and the burner control knobs or if one or more of the burner control knobs is in an open position when opening the LP tank valve. When the safety device has been activated the grill is referred to as being in "bypass".

Keep in mind that the safety device reacts to gas leaks. If a grill is in bypass, the gas connections and hose should be tested for leaks with a soap and water solution.

If you do activate the gas regulator safety device, the grill may struggle to reach high temperatures or may not light at all, even with all burners on the START/HIGH setting.

To insure that you are not inadvertently activating the safety device as you turn on the grill, please use the following procedure: THIS IS A PROCEDURE YOU WILL WANT TO GO THROUGH EACH USE OF THE GRILL.

-Turn all burner control knobs to OFF, including the side burner control knob if present.

-Make sure the grill lid is open. Open the LP tank valve and then wait one full minute. This will allow the hose and regulator to pressurize.

-Turn the appropriate burner control knob for your model grill to the START/HIGH position and then ignite the grill by pushing the ignition button.

-Turn the other main burner(s) on HIGH as well.

-Close the grill lid.

-The grill should reach approximately 500 to 550 degrees in 10-15 minutes.

When you are done grilling:

-Turn all burner control knobs to the OFF position

-Turn off the LP tank valve last.
If you have any further questions, please call our Weber Customer Service with your serial number and one of our reps will be happy to assist you.

Safety device? Who knew?

Thinking back, I think it *was* the case that the knob for my grill may have been accidentally in the on position when I plugged in cylinder A. As soon as I noticed this, I turned it off. I didn't think much of it because I assumed the regulator wouldn't care. In fact, I had no idea my grill regulator had any intelligence at all.

I've yet to try the above procedure to see how it works, but I'm psyched to see that my question and seemingly random issue wasn't random at all. It was just my grill quietly trying to protect me from blowing myself up. How nice.