Pressure Problem

[Blackcat]

I recently purchased a two burner (maker's name is withheld because I'm certain the error is mine, not his) forge and I've just started to use it.

I open the tanks -- two 40 lbs in tandem-- all the way:

 

I adjust the regulator:

 

I open the ball values all the way (closed in this pic):

And light it up. My inital pressure, adjusted with the regulator is as high as 13 but, after about 5 mins. the pressure drops slowly to about 3 in a half hour.

I've tried:

Waiting for winter to end, the tank may have been freezing -- 40s - 50 degree F temps brought no relief

Tandaming the original 40 lb tank with a 20 lb tank -- no change

Buying and tandaming another 40 lb tank -- lighter wallet, no change

Making sure the new tank was purged and both tanks are full -- nope

Endless turning up and down the black reg. knob, the ball valves (which I think should just be fully open), and lifting and lowering the chokes from the recommended 1 inch open -- nothing

A new regulator, from the maker -- same problem

I'm running out of ideas, can anyone give me any advise?

Thanks!

 

[Loneforge]

If your tanks are cold there will be no evaporation in your tanks. Try keeping your tanks in a warm place before going to forge. The faster the fuel expands to vapor inside the tank the colder it will get......Try drawing fuel from one tank till it cools off then swap to the other tank......the delay may allow the other tank to warm up enough to give good evaporation again!....Keep us posted. I run a single burner with a 20lb tank on a 30PSI regulator...........

[ThomasPowers]

It does sound like a regulator issue.  (and it is possible to get a bad one right out of the box; but 2 is much less likely)

 

 

Does the forge heat change with this?  You've mentioned that the guage changes not that the heat output changes---two different facts.

[Herb Upham]

When you changed regulators did you get a new gauge as well? ... also it appears the sliding air control sleve seems to adjusted much differently on the right hand burner ... is that photo angle artifact or is there some other reason?

[Chinobi]

if you look at the first picture, the tank on the left has a very well defined frost ring while the tank on the right doesn't appear to have any, are both tanks drawing equally in that configuration I wonder?

 

at the forge school I attend we are running the same model forges (from what I can see) and each one feeds from a 100lb tank with a splitter after the reg to feed the twin burners.  my memory is foggy but I don't think they are typically set above 10 PSI at the reg, except maybe on startup if we really need to ramp it up.  even still, we sometimes have to shut down a burner in the afternoon and run it single because they start to 'chirp' if the tank is frosting up and dropping pressure.  doesn't happen every time, just greater than zero.  used to be a huge problem when we were running them on 20 pounders when the forges were brand new.

 

try shutting down a burner (if it doesn't interfere with the work) next time that happens.

 

edit: I should add that the forges I am referencing are in Los Angeles.

[Blackcat]

Thanks for all the quick replies!

Loneforge: My shop is an old barn that leaks like a sieve. Inside the temp. is really no different that out. I was hoping the tandem set up was a good idea but I'll try them one at a time.

Thomas: I was wondering about the heat as well . . . the reason I started looking at the regulator and seeing the pressure fall was the sound of the forge got so much quieter -- less "roar-y" over the half hour, not because of the work becoming so much harder to manipulate. I'm still able to work the piece. The maker lists a really wide range of working pressures "3-20."

Herb: No, it took the first dial off the orignal regulator, and put it on the new one. Are dials a weak link? Also, you're right: the slide are at a different level; just more of my screwing around try to make things work. Usually I set them both at 1 inch opened.

Chinobi: My pieces are small enough to only be under the one burner most of the time. My first forge was a one - burner and I had the (mis?) belief that forges with more than one burner should be used with all of them running. I try just one, next time.

Thanks again for all the help. Please keep the ideas coming, I promise to try everything.

[Chinobi]

It is intended to operate with both active, but it will work just fine with only one burning. No sense owning a twin if you plan to run it single, thats just a temporary solution to overdrawing, you still need to figure out WHY it is happening. You can brick up the back a little to reduce the chamber volume if it really came down to it. Just make sure you shut the choke sleeve on the inactive burner all the way or it will act like a chimney and fry the nozzle, could even damage the rubber hose.

[arftist]

You need to place the tanks in a tub of warm water. When the water gets cold and the pressure drops, put more hot water in the tub.

[Herb Upham]

All indications are your loosing pressure from the propane source, good observation of the frost on the left and not the right tank. That indicates only the left tank is feeding propane most likely. I'd find the cause of that then use the washtub full of warm water approach for both cylinders ... just be careful, I froze a ring of water the size of a plastic wash tub one day befor I bought my 100 pound cylinder.

[Chinobi]

my guess would be that there may be some of that Teflon putty (or is it tape?) obstructing the tube or the connection, there appears to be considerable extrusion at the nozzle of the right hand tank, might be a similar deposit on the inside as well.

[arftist]

my guess would be that there may be some of that Teflon putty (or is it tape?) obstructing the tube or the connection, there appears to be considerable extrusion at the nozzle of the right hand tank, might be a similar deposit on the inside as well.

I was wondering about that too. The whole thing should be unmade, then remade with the tape or past very carefully applied. None on the first 2 threads, none in the tanks, none on any fittings which have a ground seal or bevel. Pipe dope is only for pipe threads.

[Frosty]

NO TAPE! Use the putty if necessary but no tape. Propane tends to do unkind things to teflon tape and little bits of tape get loose and plug things best not plugged. I know there is teflon tape rated for propane and things may have changed since last time I talked to the propane guys.

 

Just a wild guess but my intuition tells me the #1 tank, (closest to the work) is colder because it's drawing faster, we've established that. Why isn't the #2 tank drawing equally? I'm thinking it's because it's running into pressurized lines and the back pressure is slowing the draw significantly. #1 tank pressure is backing up the flow from #2.

 

When I was running two tanks I ran them to a manifold then to the regulator. Nothing special, tank hoses to a 3/8" pipe T, a 6" nipple, regulator, short nipple and a street t one leg to each burner. the 6" nipple provided a little reservoir to even the pressure so both tanks were feeling the same.

 

My newer forge is a 4 burner and I run it off a 100lb tank. Two burners will put a frost line on it in an hour or so but it doesn't effect performance till the tank is getting pretty low. I winter I use two magnetic engine heaters to keep it warm enough to use but it'll still freeze up after a while.

 

Frosty The Lucky.

[iron quake]

Could be the OPD valve is stuck, and that could be because of the teflon tape you've applied at the fitting connecting the tank. This fitting requires NO sealant and NONE should be used ever.