I am not certain what your setup is, so I am going to make an assumption. First, the grill you are using is a common portable propane gas grill designed to work off disposable cylinders. These grills have an integrated pressure regular and control knob and are designed to operate from 'tank pressure'; that will vary according to ambient temperature. If you are using a bulk tank for economy purposes, you should have and adapter and hose that provides an unregulated LPG supply. Keep in mind that the pressure of the LPG is the same regardless of tank size. As mentioned previously, there may be a check valve in the hose that is supposed to close if there is a situation that caused high flow such as a break in the line. The check valve will operate if the LPG tank is at fairly high pressure and the valve is opened suddenly when the gas flows to fill the hose. If the gas appliance is a high BTU one, just by operating it may close the check valve. Another question I would ask is, does the adapter/hose have a built-in regulator such as found on home BBQ grills? Those will limit the pressure to about 1/2 PSIG and that is not enough to operate a gas grill with its own regulator. The run of the mill portable gas grill needs no less than 10-15 PSIG to operate properly. There are fixed and adjustable regulators that will do the trick. If you are using a high output gas appliance such as a large camp grill, cooker or fire-pit, the regulated pressure will be much higher. This is a problem that comes up often when I am camping; there is someone nearby that is trying to figure out why their grill or stove either never worked or stopped working. The most common problem I run into is someone is plugging in a portable gas grill into the quick connect on their RV that is at the regulated pressure of 11" WC or about 1/2 PSIG. If you can even light the grill, the best you can do is warm your hands on a cold day.
