I have 2 sunjoy G-PH001PSS, when attached to the propoane tank, th unit does not light. I do not hear any gas whe turn the control knob to the on position. When i remove the gas line from the heater the gas will come out of the line as if the unit is not accepting the gas. Just filling the line but not ging into the heater. Both uniots arre doing the same thing.

From the Troubleshooting Guide - Check the Obvious Turn on the gas and listen at the burner to see if you can hear the gas arriving.
If the patio heater has an electronic ignition system make sure that there is a spark. If there is a spark but the heater will not light up, try using a lighter or burning spill to light the gas. Be ready for a flash over if you have been trying to light the gas for a while-there might be a small cloud of gas near the burner.

Start at the Bottom The most likely reason that a gas heater will not work is that there is no gas. Take out the empty gas cylinder and replace it with a full one. Often you will feel that there is still gas in an empty cylinder but there is not enough to create the pressure needed to drive the gas burner. An empty cylinder will feel light.

Check the Gas Regulator The gas regulator is the connection of the gas cylinder to the gas pipe that takes the gas up to the burner. Some regulators have a flip switch that prevents the valve in the top of the cylinder from being depressed-effectively an "off" switch. If there is such a switch, make sure that it is in the "on" position.

Check the Gas Pipe Although it is most unlikely that the gas pipe can get blocked, remove the gas pipe from the regulator and from the gas inlet at the top of the heater. This pipe is pressure fitted and held in place by pipe clips. Blow air through the pipe to ensure that it is clear.

Check the Burner The burner will be a very simple assembly. Take each part off in turn and check for any blockages. Also check that the burner apertures are set correctly. Beneath each burner is a small chamber in which air and gas are mixed. Make sure that the gas and air inlets are clear.

If Your Heater has a Pilot Light If your heater has a pilot light, there is the possibility that the thermo couple has failed. The thermo couple is usually shaped like an inverted "v" and sits in the flame of the pilot light. The temperature acts on the thermocouple to keep the gas supply to the burner open. A good indication that the thermocouple has broken down is that the pilot light goes out when you try to turn the heater on. Thermo couples are readily available patio heater parts and usually available from stock.

If you have carried out all the checks and the heater will still not light, you can repeat all the checks more slowly and carefully or take your heater to a specialist for a service.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/steven_7f54ab9063554f66

Need to clean or replace it,supply tanks is empty, low pressure,bad regulator, not enough air supply etc. Kinked supply lines.?

Try using a match, sometimes spark is not hot enough. be carefulle.

The troubleshooting manual says low fuel, low fuel and cold weather and kinked supply line. Beyond this I would need to know if something happened to the unit like it fell over or was taken apart. Best, Joe

It could be dirty nozzle or dirty line
Unscrew every thing in the nozzle and control valve section and clean gas line and reinstall and try it

Either the temperature probe (at the pilot light) that signals the gas valve to open is defective or the gas valve is.

I would read the customer reviews on this product , looks like nearly 70% of consumers are less than happy with this unit.

1500 watts is the units peak output, and drops to around 600 as it warms up. My hair blower puts out more power.

1500 watts is LESS than the output of a small element on your stove top. The real measure of heat is not watts, its BTUs and btus from gas are much cheaper than they are from electricity.