Gas-Fired Steam without Electricity?

NTL1991

After losing power for close to 20 hours, I started thinking about the different methods of heating and generators and inverters and all of that kind of stuff you think about when you're without power and have nothing to do except worry about frozen pipes.



My single-zone gas-fired boiler (with standing pilot) requires 120V to operate the gas valve, vent damper and circulator.



If I had a one-pipe gas-fired steam system (which I've had in the past), wouldn't it be possible to operate it without electricity in the event of a power outage? No circulator, no zone valves... What about the gas valves? Most typical gas-fired water heaters don't need electricity to operate their gas valves. Are these types of gas valves available for boilers? It sure would beat having to hook up a generator, or use a battery and inverter after doing all of the wiring modifications to get the circuit powered.



Nick

Tim McElwain

"Powerpile" systems used on

many steam boilers all over the Northeast have run no matter what happens to the grid. They use a pilot generator that puts out about 750 millivolts which is sufficient to operate the gas valve manufactured for that purpose



They are no longer on gas equipment since the mandate of 1979 for dual seated "redundant gas valves" in order to insure a safer operation the odds on two valves failing to close versus one valve. Powerpile valves could not operate with a dual valve set up so they are no longer allowed on heating equipment. We still see them on decorative appliances, unvented space heater's, pool heaters. The Amish still have access to powerpile in some areas. They were a great system. See my posting about my experience this weekend with the snow storm on the Wall.

NTL1991

Thanks

Thanks Tim,



What kind of gas valves do regular run-of-the-mill gas water heaters use? For safety, I'd imagine they'd have to have double-seated gas valves as well, and they don't use line voltage. If they don't have to use double-seated gas valves, why do boilers?



I'll be sure to take a look at that post of yours; It sure was one hell of a storm! National Grid wasn't too bad in getting the power back on here in Cranston, but I definitely think I'll be investing in a small generator next year at least to power the 3 boilers (mine being one of them) in my 3-family.



Nick

Tim McElwain

Water heaters use

a single seated set up with total regulation of gas pressure and incorporate an ECO (195° fusible link safety) which is a one time fail system. The valve is operated from a standing pilot system using a 30 millivolt thermocouple for the pilot safety system. The temperature is controlled by the rod and tube inserted into the water which is attached to a single seat mechanism. The ECO would typically be considered the safety versus a dual seat application.

SWEI

so would it be possible

to setup a series valve arrangement (like we see on commercial gas trains) using two modern millivolt valves, with two pilot TCs separately heating?

Tim McElwain

When you say modern

millivolt valves what make and model are you talking about? It really is not feasible to do what you are asking. I have done old large gas actuated boilers with two safety pilots, retrofitted to a powerpile system with one pilot handling the generator (750 millivolts) and the other pilot using a cabinet mounted 30 millivolt pilot safety tied into the 750 millivolt valve. This insures that if any pilot system fails the complete boiler is shut off. That would not however cover the design requirements for redundancy today.

g10

Powerpile systems work great

They were great system . There were only three parts to worry about gas valve/ thermostat / thermal pile . If reliable power was a problem. This system was the answer . And with customers wondering about the grid these days I tell them keep it working . If the power goes down you will still have heat. So there not as efficiency as the new heater. But there run a long time before you had a problem. 

Not like the scrap you got today. No power no heat . Hook it up to a generator that has voltage dips or spikes as other appliances kick in and out . you can kiss your electronic parts by by and then have one really pissed-off customer that just spent big bucks on a high tec boiler and generator after you ripped out a power pile system. Just to make it more efficient when the system wasn't leaking and working??????

JUGHNE

Once apon a time in the West...

I have replaced at least 3 gas furnaces from the 50's & 60's that had a gas valve labeled as 24 VAC or 12 VDC.  Old timers said that in a pinch they would haul in a car battery to power the gas valve.  The high limit would still be in this circuit.  I believe they would remove the blower door to get gravity air flow from the basement thru the duct work.  Of course there was no door safety switch. And the entire house was well ventilated.  This was always on LPG/propane also.  I've never done it and you didn't hear it from me!  Perhaps an urban legend.  Has anyone else heard of this?  But Robertshaw does have conversion kits such as 705-402  and millivolt kit 710-296 for NG/112,000BTUH.

jumper

ah the bad old days

I remember industrial facilities that powered all critical equipment and processes with steam because steam was considered far more reliable than electricity. Hang the cost. Things got interesting when oil replaced coal. Batteries or generator for igniter? Nowadays even refineries buy electricity.



New Orleans and Fukushima learned the hard way not to depend on electricity.