OPD Valves

[reedbr]

My propane tank just ran out and the PO (previous owner) had not  converted to an OPD valve yet.  The local places want $100 to install an OPD and recertify the tank, and it will take a week to get the parts and do the work.  New tanks are $160.  That is a 10lb 2.5 gal (I think) aluminum tank standard on the MKII's.  I went to do some emergency research and have found some interesting information.  First, the DT number on the tank stands for Dip Tube length, not Department of Transportation.  DT is the critical factor on valves.  It turns out that my DT is 4.0, the exact same as the standard steel BBQ grill 20 pound tanks. I called Sherwood (valves) to confirm my suspicions, that you can just take the OPD off of an empty steel 20LB tank and put it on the aluminum tank.  They said yes, same valve, no problems.  Use teflon tape or gas sealant on the threads.  If you use teflon tape, only use it on the upper part of the threads.  If you cover it all the way down, small pieces could end up in the tank and there would be a (relatively small) risk of clogs.  
 
 Another intersting note is that there are inline OPD valves and those that work on a pivot.  You want inline which is what Sherwood makes.  Others like Manchester and Stopvalve use the pivot variety that when full, might knock against the top edge of the tank when the boat rocks.  This could be annoying.
 
 So I'm off to the store to find a Sherwood valved BBQ grill 20# tank to see if this is all true.  After the valve swap, I'll see if I can have it recertified too to be safe.  I'll report back later.
 
 C34 mkII "Ambitious"
 Solomons, MD

[Ro Hill]

Great information.  Another reg. requires that all tanks be recertified every 10 years.  If you go to a fill station that's a "stickler" they will check for that date.  I've found that the steel tanks at 1/2 the $$ of aluminum tanks work great.  The cost of recertification of a steel tank is usually about the same cost(or more)of a new steel tank.  They do not rust like on your BB grill because they're in a "propane locker".
  A thought.   APACHE #788  ;)

[reedbr]

It worked!  It just so happens that the freshly emptied BBQ grill tank on my deck had a Sherwood valve.  However, removing the valves without damaging the soft brass is difficult.  I had to go get a monster crescent wrench and rig a clamp for the tank with 2x4's.  I also added another foot of pipe on the wrench to break the valves free.  Once done, I performed the swap in a heavily vented area. Then I had it tested and filled.  I took the old steel BBQ grill tank (with my old aluminum tank valve) to a Blue Rhino tank exchange.  The tank swap cost me $13 more with the non-OPD valve.  
 
 My aluminum tank date is Sept 1996, so I have ten years from there and a recertification is good for 5 years.  Thanks for the tip on steel tanks Ron.  I looked and it seemed like they were around $60 empty.  That was my close second option if the right valve wasn't just sitting on my back deck waiting for me.  
 
 One last note, the replacement BBQ steel tank for my grill had a non-Sherwood valve.  Yes, it made a ding, ding sound when it was rocked, so I am guessing it was the pivot variety.  
 
 While doing this, I had one more thought.  How can you rig a low pressure backup "T" on the system to accept a portable 1-lb canister.  This would be useful if you run out on a trip.
 
 C34 mkII "Ambitious"
 Solomons, MD