How do i eliminate moisture from an underground,natural gas galvanized gas line. I have no gas flow to my garage or my 75k garage heater.

When natural gas or propane burns, water vapor is given off within the flu gasses so a bit of condensation in, off and around the flu discharge is quite normal. If it is a high efficiency furnace with the pvc flu pipe, they must be pitched properly BACK TO the furnace so the moisture will drain backwards and out a drain tap at the bottom of the riser. That style of furnace will have TWO drains...one up high for the air conditioner coil and one about 16" up from the bottom of the furnace off of the 'condensing coil' that the flue gasses pass through to extract a much greater amount of heat from the burned gas.

Many flu pipes are installed incorrectly which causes water to drip outside instead of back to the furnace and this usually results in huge icicles hanging off of them in the winter and eventually the partial blockage causes the flu's pressure switch to open.

If you have regular galvanized flu pipe, you have less than a 90% high efficiency furnace and the resultant flu gas temperature is much higher with a much greater quantity of water vapor in it. A little condensation is somewhat normal on the top of the flu cap as the hot moisture laden vapor comes in contact with the cold and dry outside air. If the moisture is all over the galvanized flu pipe in the basement, you are possibly venting into an oversized and unlined masonry chimney. IF that's the case, the chimney should really be lined with a flexible liner and properly connected to the furnace and water heater (if gas fired) with the proper connections and configuration.

It should say on the tag inside the cabinet, or on the gas valve. Another indicator is that natural gas typically is fed through a 3/4" galvanized pipe, LP is often run through a 1/2" copper pipe. Be sure before trying to fire it up.

Replace water heater, before it leaks on the floor
Rusted out inside

Check the flame sensor is clean . Also check out the pressure switch . Check out the snap disk high and low temp .

The orifices for a propane heater are much smaller so you will not be able to get the natural gas to flow properly with the current orifices.

The both the natural gas and propane valve are 1/2 psi so the valve can be used but the regulator for propane is typically 8-11 inches on the wc table and the natural gas is typically 3 lbs on the wc.

You may be able to drill out the orifices in the burner and in the pilot ods and get the unit to work.

Check for a fuse either in-line or on the circuit board. There should be 24 volts going to the thermostat. If not, you have either a bad transformer or a bad thermostat wire. Jump out the terminals that the thermostat wires are connected to. This should force the unit to fire. If not, bad circuit board.

No, Exhaust vents on heaters should always maintain vertical orientation because heat rises and creates a natural drafting drawing the fumes out. You have a monoxide poisoning situation otherwise.

I hop you did not bury the galvanized. As for the heater, try searching Haywards dervice locator for a local warranty shop. Most will repsond within 48 hours or so. Messing with the unit too much risks voiding warranty coverage.

http://www.haywardnet.com/locator/

Select service and keep increasing the radius until you find someone who can fix it on Hayward's dime.

The pressure switch to which you are referring is the switch connected to the suction side of your induced draft fan. This pressure switch will have a hose connected between the switch and the induced draft fan. Please let me know if you need any more assistance.

lp or natural gas sounds like moisture in the line look for a trap should look like a tee with a cap on it turn off gas and remove cap and see if any moisture in line replace cap and turn on gas check for leaks with soapy water and a small brush if not moisture it could also be air in line if so it will bleed itself out in a little while and work normally