I have a atwood gas furnace model 8520 IV in my rv I was told it did not have enough gas pressure, do you know how or where to adjust on valve?

It could be any of several regulators. Do you have a manometer to measure gas pressures (inches of water column)? If not, you can't even start the process. Adjusting gas pressures is not hard if you have the correct tools and knowledge, but if not done EXACTLY RIGHT you can have a major catastrophe on your hands.

EPM

Who told you this, and how do they know?

I agree with EPMiller. There is more than one pressure regulator in a RV and you better have the right tools and knowledge to service the appliances. LP/Propane gas is unforgiving.

When I took the furnace in the tech put a new ignighter board in it hooked it up on his bench with Lp that had no regulator on the hose and it worked. When I put it back in RV it did the same, ignite and go out. Atwood said it was the pressure anyway I thought it might be or hoped it was sail or limit switch. Adjusting pressur is out of my reach.

I forgot to mention, when I hooked the furnace up to an external lp hook up with a regulator, it duplicated the problem as in the rv. Where the other tech did not have a regulator.

If I understand your posts correctly, it sounds to me like the gas valve itself is the problem. A heating technician will be able to sort this one out easily once he can get to the whole system, not just parts on a bench.

EPM

That is the same furnace I had in a 35 foot pull behind trailer made by Wilderness. You need to check the pressure of your system first. The regulators/auto switchover valve (if so equiped) in the front near the tanks have been know to go bad. Now if the oven and burners light normally on the stove that is usually a indication the pressure regs at the tanks are OK but that still does not mean for sure the pressure at the furnace is OK.

The atwood furnace I had worked great except for the very small ants the liked to plug up the main burner orifice every year for some reason. I had to pull the furnace every year and remove the burner tube to clean them out. The funny part is that they were always dead. I guess the real cold weather in the winter killed them.

Manual if you need it

http://www.atwoodmobile.com/manuals/furnaces/MPD%2033179%20SP%201.08.pdf

Parts list

http://www.ntpdistribution.com/PDF/Via/41-HF-furnaceqkchart.pdf


http://www.fourwheelcampers.com/atwoodfurnaceinstructions.pdf

GREAT manual listing tools and usage for many models.

http://bryantrv.com/docs2/docs/hflamefurn04.pdf




NOTE if it is cold in your area and your tanks are not completely full it is possible they will also be low on pressure causing the problem. Hope all this helps

I sure appreciate all of your help. Will let you know what it takes to fix. Thanks again to all of you.