online service manual for Unitrol water-heater pressure-regulator ?

Out of pure curiosity, I'd like to know how one adjusts the Unitrol gas valve on my 50-gal water heater. Whirlpool customer support hasn't a clue, and Robertshaw has hidden its Unitrol information pretty well.
The water heater poses no danger, but no doubt one of the alt.hvac thunderbolts will explode. I'd appreciate an accurate answer from a cool sober head.
Thanks, JP
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On Sun, 19 Dec 2010 13:47:15 -0800 (PST), jake

    I see you're one of that rare breed that likes to get pissy about the forum and everyone in it before even getting an answer to your question.
    Trying to beat the christmas 'pissy time' rush, are you ?
    Asswipe.
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Oscar, on top of the on/off/pilot knob is a green slotted cap with the words "Main Burner Pressure". And there's a pressure tap at the outlet. These two clues strongly suggest that adjustment is possible.
I do appreciate your effort and civility. -JP
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Yes and it requires a manometer to set it properly. Natural gas (methane) valves have an internal regulator that drops the inlet pressure to 3.5" water column, LP valves pass the 11" WC straight through, and have a smaller orifice to match at the burner. IIRC 12" of water is .44 PSI. Given a fixed burner and air shutter size manifold pressure controls BTU output alone. Orifice size controls fuel/air mixture ratio and BTU output. Apparently methane requires a richer mixture than propane/butane hence the bigger orifice size and lower pressure.
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The manometer is no problem; I have a beautiful manometer.
Specs on the water tank call for "5in Manifold Pressure" (not 3.5"). No doubt there's an acceptable range (e.g. 4.5" ~ 5.5"). And I'd like to know which direction to turn for higher and lower, as I don't fool around with natural gas. That's why I'm hunting for Unitrol specs.
-JP
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On Sun, 19 Dec 2010 22:20:14 -0600, "Oscar_Lives"

    That's more like it :-)
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On Mon, 20 Dec 2010 08:12:33 -0600, "Oscar_Lives"

    They're pretty consistent like that, I've found.
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Oscar, on top of the on/off/pilot knob is a green slotted cap with the words "Main Burner Pressure". And there's a pressure tap at the outlet. These two clues strongly suggest that adjustment is possible.
I do appreciate your effort and civility.
-JP
Yes? but there is another clue
DON'T FUCK WITH SOMETHING THAT IS NOT DESIGN TO FUCK WITH!!!
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