HOW CAN YOU TELL IF THE PILOT LIGHT IT LIT ON A H200 ABOVE GROUND HEATER

there are a few things you can check. make sure you have a good fuel supply. make sure the pilot light is lit. (just because the pilot is on doesnt mean you have good fuel supply). the pilot may be out of adjustment from the burner rail. the igniting burner rail may be dirty or blocked

since you are not quoting an error code, i will assume that you have a millivolt heater. that being said, refer to owners manual pg 36/37

short of that, make sure the switch for the gas control block is on. little black switch inside heater on gas block (by pilot knob) after that, it can be a problem with any of the safe guards. check to be sure you have adequate gas pressure.

1) Get more air to the water heater and see if problem continues.
2) Read the following pdf-s for things that might apply to your situation.
http://waterheatertimer.org/images/Negative-pressure.jpg
http://waterheatertimer.org/pdf/Attic-Ventilation-and-Pilot-Outage-in-Gas%20Water-Heaters.pdf
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf

3) Read pdfs above first, and then Add a comment with missing information below, for possible do-it-yourself help.
Does this water heater have a blower?
Is gas valve electronic? Or does gas valve have a dial?
If gas valve is electronic, have you checked outlet with circuit analyzer?
Did pilot light work correctly for a while? If so how long?
Where is water heater located? Hot attic? Closet? Garage? Is area dirty and dusty? Has air intake been cleaned?
What color is pilot flame? Clear blue or yellow-or-orange?
Have you inspected inside of combustion chamber for dripping water?

More than likely the thermal couple is defective. The thermal couple is a safety device that shuts the gas off if the pilot goes out. If it is defective the pilot light will not stay lit. The thermal couple is the device that the small copper line goes to. It is mounted beside the pilot flame and the flame much touch the TC for it to work. If the flame is not touching the TC bend it until it is in the flame. If it is touching the TC then replace it.

Typically there is a safety device directly above the pilot light that must be up to temp for the gas to flow. You did not specify if the pilot is lit. If not, hold the lighter at the pilot light while depressing the button for one minute. This allows the sensor to warm to operating temp, thus allowing gas flow. Once pilot is lit adjust the temperature accordingly.

I have the same heater and have been struggling with it since we purchased our house 6 years ago. I am very familiar with the "tapping" method and just this year learned that I could jump the TH connections to consistently get it to light. Finally that too became unreliable as the heater would shut off shortly after I jumped it. I used a voltmeter to test the millivoltage coming from the pilot generator (assembly) and found that it was only around 300mv, whereas supposedly 500mv is required to open the gas valve. Before investing $70-$100 on a replacement pilot assembly I decided to take it apart and see if it needed cleaning. There was a bit of buildup on the thermocouple that I removed with 150 grit sandpaper. I re-installed the pilot assembly, lit it, and retested the mv. I was disappointed to see that the millivoltage was still only around 300, but as I watched it began to rise until it eventually reached 500. I then turned the thermostat on and adjusted it until it was higher than the temp of water and the heater instantly turned on. So far so good....

I have a hayward h-2001 natural gas heater that I wish to change to propane. perhaps we can swap parts. [email protected] 920-324-5652

Replace the pilot generator if output is below 400mV.

Yes it does. Flame rectification is carried back through the ignitor assembly ground. Be sure all the points of contact are rust free between the ignitor assembly and the chassis.

What type of heater is this, millivolt or electronic, is there a standing pilot if so will pilot stay lit, if pilot does not light you may have an obstruction in it which needs to be cleaned.
as well as checking gas orifices for blockage