Pilot light i have a dayton propane heater we turn on the thermostat it clicks then the heater clicks pilot come on then gas and then it goes out and blows hot air out the pilot or gas wont stay lite we need to know what the thermocouple looks like for this model

Help in the link, but you LPG Gas fitter should know all this. All gas installations must be done by a gas certified technician.

https://www.google.com/search?q=Dayton+Furnace+3E847+LPG+Pilot+orifice+size

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For (fire) safety, there is usually a thermostat that will turn off the gas if pilot light goes out.

So when you try to light the pilot you will have keep press & hold the pilot gas supply for at least 10 sec until the thermostat is heated up. Then only when the pilot light stays on continually, can you turn on the burner.

Forget about changing to a High pressure regulator!

Check propane pressure, also check for water or other contamiants in the propane.

If this is a standing pilot system, turn the gas valve to pilot position. push in the knob & hold while lighting pilot...keeping holding knob down for a minute... this will pick & hold the gas valve. Let go of the knob & see if the pilot stays lit, if it does, then turn the knob to on position & the furnace should start if there is a call for heat from the thermostat

Find where the gas line connects to the gas valve on the back of the heater, from the gas valve, follow a small aluminum tube going into the back of the heater. There may be a removable door to access the pilot assembly. If there is no aluminum tube, the unit has electronic ignition and no pilot lite. Turn the gas knob to off, then to pilot. Hold the gas valve in and with a long match or gas grill lighter, light the pilot. Continue to hold the knob in for about 30 seconds. After that, release the knob and check to make sure the pilot stays lit. If so, rotate the knob to ON. The thermostat will kick the burners on.

If you're using a 20lb propane tank (Gas Grill Tank), that may be the problem. Turn off the propane tank at the tank valve and disconnect it from the tank. Wait 5 minutes and reattach the heater hose to the tank. Turn the propane tank valve on very,very slowly until it's all the way open. Try lighting your heater now. If the pilot flame height returned to normal, that was the problem.

FYI - The Thermocouple has nothing to do with the length of the pilot flame. It's a safety feature that stops the gas if the pilot flame goes out for any reason.

Hope that solves your problem. Please let me know.

Rich

its most likely dirt/rust in your burner assy , but as its 15 year old and propane do your self a favour and get it inspected by a registered gas/propane engineer .
ive witnessed propane explosions at first hand and they are scary

Check your thermocoupling to make sure that it is sensing flame. You can tell if it is good or bad by the white on the tip of the flame sensor. The other problem would be a blocked or closed flue pipe. Make sure that the cap is not smashed down on the pipe on your roof

get someone to check the gas pressure that is poss problem gas company if nat and the lp supplier can do it