I have Dayton 3E250 ceiling hung heater. It was originally LP but was converted to NG. I want to convert it back to LP. Does the gas valve also need to be replaced? Thanks

Question edited for a lot more clarity.

From the maker.

Fuel Conversion Kit NG to LP

Mr. Heater https://www.mrheater.com > fuel-conversion-kit-ng-to...

Fuel Conversion kit for changing NPP overheads to LPP and from NG to LP. Kit includes all necessary labels and components required for the complete ...
US$33.69

Mr. Heater ventless wall heater convert to LPG

The Garage Journal https://www.garagejournal.com > ... > Heating and A/C
Mr Heater supports converting the Big Maxx 50 and 80 from NG to LP and sells a kit with the orifices for $25. https://www.mrheater.com/big-maxx-fuel- ...

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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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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.

orifice sizes will increase since goin from lp to nat gas.......to convert appliances you will need diff gas valves, nat gas and propane will have diff pressures

Dayton is primarily sold by www.Grainger.com . You must purchase a re-jetting kit (Natural Gas Valve) from them to accomplish this.

Grainger Part # Natural Gas Valve
Item # 1FEK5
Natural Gas Valve, For Use With 5VD61, 5VD63, 5VD65 DAYTON
1FEK5 4401 Usually ships
1-3 Days 1 $144.30 Sale Price$115.44 See All: Parts

you need to change reg spring pilot injector and burner injector and reset pressure to heater , should be able to buy kit on line

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

you need too change the orfice about 10.00

That heater was not designed to be safely converted to Natural Gas. Even if you could convert it, it would cost more to do that than to replace the heater.

If you know a dealer or repair company,they can order orifices to change out in the unit.