Dayton i need the orifice numbers for a dayton 3E839 ng furnace heater.

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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They don't use a thermocouple, They use an ignitor and a flame detector rod.

You have to contact the manufacturers rep in the community to verify that the particular model of Dayton heater has the capability of NG to LP conversion. If it is, the natural gas kit will include a new set of brass 'spuds'...typically referred to as 'orifices'....for the main burners. The size of the hole will be considerably larger because NG contains less btu per cubic foot than LP gas.

There will be a replacement pilot orifice for the pilot assembly. Removed and installed usually a 1/2" and 7/16" wrench. This orifice will also have a larger diameter opening.

There should be a regulator to match the 100% redundant gas valve that is in your heater. Note though, that there may be several regulators in the kit to match any one of several brand gas valves that could've been installed on your heater....Robt Shaw, White Rodgers, Honeywell. They will NOT interchange with one another. Follow the directions closely to ensure installation is done correctly...you are working with a volitile, explosive gas !!!!

There may or may not be a set of air shutters to fit over the ends of the burners for primary air adjustment. Natural gas may require a bit of air adjustment to get the proper flame.

Thoroughly leak test everything when done, then leak test again.
If you feel you are in over your head, you probably are so contact a reliable service organization to do it instead. But at least you now have an idea of what is involved.

Is the manual gas valve open, either plumbed or on gas valve? It may sound dumb, but it happens. Are the wires connected to the gas flow solenoid securely?

When the heat call initiates heat cycle, can you observe the ignitor? If it tries to ignite, is there gas entering the burner? How clean is the gas orifice? If the orifice is plugged, best to simply replace it.

Try national energy the are on line

I would contact grainger industrial suuply at www,grainger.com/dayton heaterparts. They are the main distributor of dayton parts and if you have your model number and serial number they can get you the proper kit to convert.Make sure you specify that you are wanting to go from N.G. to L.P.. Thank you. This is a good company. I have dealt with them for years and they have nice knowledgeable people usually have what you need and ship promptly.Check with them to see if they have a distributer close to you and you can go pick it up yourself. Thanks again.

you will will have to change the reg as ng burns at 4inches and lpg burns at 14 inches and pilot orffice if fitted

Hello,They probably make a universal one that can replace the factory one.The number off the old part itself is needed to cross reference the match.

At 180*f-200*f high limit saftey

the orifice that comes with the unit has a starter hole only needs to be drilled out, in the instructions is a chart for altitude de-rating.