Robertshaw gas valve questions

hemiguy

Hi.
I have a robertshaw gas valve 7000AST-LP-3 on an Empire direct vent heater. It is a hydraulic snap throttle valve.
It is working ok, except sometimes when turning on it makes a noise like a gas rushing sound. Not smooth like usual.
The valve label says no regulator, so what regulates the gas pressure from the tank?
Does the operator provide regulation?

After looking at the Robertshaw gas valve catalog I am a bit confused.
Some valves say they can be used with either LP or natural gas. How does that work?
Some have regulators, some don't, some can be converted to LP.
Any explanation would be helpful.

Thanks,
John

Tim McElwain

I have a robertshaw gas valve 7000AST-LP-3 on an Empire direct vent heater. It is a hydraulic snap throttle valve.
It is working ok, except sometimes when turning on it makes a noise like a gas rushing sound. Not smooth like usual.
The valve label says no regulator, so what regulates the gas pressure from the tank? THE SECOND STAGE REGULATOR SHOULD BE SENDING ABOUT 10" w.c. PRESSURE AND THEN THE FLOW IS CONTROLLED BY THE ORIFICES ON THE BURNER. A LOT OF SPACE HEATING UNITS DO NOT REQUIRE A REGULATOR ON LP.
Does the operator provide regulation? NO!

After looking at the Robertshaw gas valve catalog I am a bit confused.
Some valves say they can be used with either LP or natural gas. How does that work? WHAT VALVES I WOULD HAVE TO TAKE EACH VALVE INDIVIDUALLY TO ANSWER THAT FOR YOU.
Some have regulators, some don't, some can be converted to LP.
Any explanation would be helpful. MOST VALVES USED ON NATURAL GAS REQUIRE A REGULATOR BECAUSE THE INLET GAS PRESSURE CAN FLUCTUATE MUCH MORE THAN ON LP.

WE COVER ALL OF THIS IN OUR TRAINING CLASSES AND IN OUR MANUALS. CONTACT US AT GASTC@COX.NET.

Thanks,