To check the gas pressure of your portable propane heater, you can use the pressure gauge for it. You can never tell if the pressure used is correct or not by simply looking at the burner. You need to contact your customer service if they sell you the test kit with low pressure and you are not at all comfortable with it and the procedure as well. Furthermore, you can contact the distributor or even the gas provider so that they can check the pressure used by your heater. If there is NG gas pressure then you need a WC of minimum 7 in. to 13.5 in. along with thee many fold pressure of WC of about 4.0 in.