need help please

[bigstevemex]

hi i have just registered and have a bit of trouble.i recently bought a 2nd hand boc lite oxy set which was almost new.no bottles.i have got new 1/2 size cylinders and set it all up but no oxygen is coming out of the torch. it is all set up and connected.there is acetalyne at the torch and it lights but no oxygen.if i disconnect the hoses and gently open the cylinder valve acetalyne comes out of the hose at the torch end.if i do the same with the oxy nothing comes out.i think the hose is blocked.if i blow down the disconnected hoses the ace one is clear but the oxy one is not.i have gas welded years ago and am mechanic with 20 years experience but not sure about this.any help or sugestions appreciated thanks steve

 

[wyn]

The hose may have a fitting with a one way valve....maybe try the hose the other way round.

I have had a similar problem before but can't remember if it was oxy or propane.

 

[gavuk]

If there are flashback arrestor's fitted,they might need resetting or as Wyn says...look for check valves on hose

 

[bigstevemex]

even if the hoses are disconnected i can blow down the ace one but not the oxy one.there is something in the hose that could be a one way valve but its in both hoses.they can only go on one way round because of different size unions.when i look down the hose from the torch end i can see a brass bit that looks like it blocks the hose but its the same in both of them.is there a valve in the hoses and could it have failed?the hoses are unused so in theory should be good.

 

[wyn]

Have you tried blowing down the other end of the hose.

As you say the hoses haven't been used before maybe they have had the wrong ends fitted.

I have fitted a check valve on the wrong end of the hose once or twice.

 

[eil]

If they are new hoses and you cant blow, try sucking.

 

[Bsmith]

Any arrows on the check valves?

 

[Pnumac]

Does Oxy come out of the flashback arrestor when the oxy hose is not connected? If 'No'
then take off the FBA and try again, if 'Yes' then your FBA is knackered and it has to be replaced, If 'No'
then your oxy reg could be knackered so replace it
BUT before you do all this please make sure the oxy hose is connected correctly i.e. hose check valve at torch end and plain nut and tail at FBA end.

I always have a bit of a problem with people picking up second hand equipment that they dont know the history of. Sometimes the savings made on 2nd hand gear are just not worth the risk. I have seen the results and consequences all too often