After some time lurking around the forums I realised I was spending too much time here and a short while later it was clear to me, that this was not going to change soon. So I became a member. Hello everyone, it’s nice to be here 
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I started playing tin whistle about six months ago after hearing John Sheahan of the Dubliners. After browsing around Youtube and hearing some recordings of Planxty I had to play the pipes. Or at least try it. I got a practice set around 3 months later and after some initial difficulties it is going quite well. I still got quite a bit of a death grip but hope this will go away with practice.
But despite practising the bag and bellows technique pretty regularly, I got a problem which has been bothering me for some time. It sometimes happens that I pump the the bellows with my bag, the air enters the bellows and does not go into the chanter any more and I have to stop playing. Most of the time everything works quite well but it seems to me, that before the air solely enters the chanter I always pump a bit of it back into the bellows. Is there a way of using the bellows to prevent this? Although it does not happen very often, I always fear that the next bag squeeze might pump the bellows so it interferes a little with my practising.
Thanks for your help.
You seem to have a problem with a valve. Check if the valve in the blowpipe of the bag closes of the inlet properly and make sure the ‘hinge’ is on top so gravity will close the valve.
And you can take your valve out to adjust it by sticking your finger through the inlet hole and then “grabbing” the edge of the inlet valve that is inside the bellows and pulling a bit. Do it along the inside rim at different places until it starts to come out. The valve makes a seal with the paddle of the bellows by a wrapping of hemp, etc. You can easily get it back inside by pushing it in after you’re done.
I think the issue just got confusing. I was talking about the valve in the blowpipe in the bag, that would be responsible for air flowing back. Try stick your finger up there!
My mistake. I read and responded prior to morning coffee… carry on.
Not to worry, did my share of pre-coffee posts.
Thanks a lot for your replies. I tried to pull out the blowpipe to see the valve but I can not get it to move. Can the blowpipe normally be removed? Maybe I just need to put in a little more strength, but I do not want to break anything.
Sometimes it is a bit difficult to practice by myself, you never know for sure what the problem really causes.
Usually, there is some sort of interface on both ends of the tube between bellows and bag. Look for a joint in the stock on the bag end and see if it twists. The valve should be inside there. Maker or photos would help.
I was not able to get the blowpipe out by pulling but the combination of twisting and pulling worked well. The hinge was not completely on top so twisted the blowpipe a bit and put it back in. Everything worked a bit better than before, but I still had the feeling of pumping a bit of the air back into the bellows before the valve closes. So I decided it was a good idea to put a bit of wax on the bottom of the valve to make it close more easily. The result was, that the valve stopped working completely. After the initial panic 
I removed the wax, made sure the hinge was exactly on top and now it seems to work! I did not pump air from the bag to the bellows anymore and I hope it won’t happen again. Thanks!
Wannabepiper: Nice cat!
It is worth putting a little mark on the blowpipe so you can always check the alignment. A lot of pipemakers put a mark on the blowpipe to show where the hinge is tied in.
You can also check to see if the leather is flat and completely closing the blowpipe. Leather can get dry, harden and curl up a bit.
As Mr Gumby said, leather can dry out. While you have the valve out of the stock you can rub a TINY amount of almond or olive oil into the sealing side of the leather and press the leather into its’ seat with a warm spoon. This will help give you an airtight seal. You can do the same with the bellows valve as well. Only use almond or olive oil though, linseed and walnut oils will dry.
thank you for that advise Mike
I have a bit of the same problem