Tender with C7 valves - so much air escapes when inflating

[RogerFoxTerrier]

I've just got a new (2nd had) inflatable dinghy which has C7 valves, which I've never had before. On inflation I insert the pump, turn it clockwise and it inflates in no time. But by the time I remove the pump and pull the valve back to the lock position, I've lost about 20% of the air! This seems crazy. Am I doing something wrong?

 

[Sticky Fingers]

Valve should be up in the lock position for inflation, allows air in but not out. You're inflating it in the deflate position I think.

 

[ash2020]

I've found that my electric pump isn't powerful enough to have the valves in the closed position. It works quickly in the open position but, as you say, when you take the pump out and try to close the valve quickly you still lose a lot of air. The only way for me is to do most of it with the electric (valves open) then close the valves and use a manual pump for the final pressure.

 

[Plum]

I've just got a new (2nd had) inflatable dinghy which has C7 valves, which I've never had before. On inflation I insert the pump, turn it clockwise and it inflates in no time. But by the time I remove the pump and pull the valve back to the lock position, I've lost about 20% of the air! This seems crazy. Am I doing something wrong?

As Sticky Fingers, your valves are in the deflate position. Put your finger in the valve to depress the valve spring and rotate 90 degree then release. In the inflate position the valve spring is in a higher position than in the deflate position.
Edit: my electric pump works very well with the valve in the inflate position.

 

[RogerFoxTerrier]

I've found that my electric pump isn't powerful enough to have the valves in the closed position. It works quickly in the open position but, as you say, when you take the pump out and try to close the valve quickly you still lose a lot of air. The only way for me is to do most of it with the electric (valves open) then close the valves and use a manual pump for the final pressure.

Ah OK, I'll give that a try. I'm currently using a DeWalt leaf blower, which pumps it in no time but does struggle with getting it nice and firm.

 

[RogerFoxTerrier]

As Sticky Fingers, your valves are in the deflate position. Put your finger in the valve to depress the valve spring and rotate 90 degree then release. In the inflate position the valve spring is in a higher position than in the deflate position.
Edit: my electric pump works very well with the valve in the inflate position.

Yes I do that and it inflates no problem - but it doesn't return to the locked position when I remove the pump and the air shoots out before I can close it.

 

[catalina1]

I use one of these

Leafield Marine Pro Inflator Hose Adaptor for C7 & D7 Valves​

 

[RogerFoxTerrier]

I use one of these

Leafield Marine Pro Inflator Hose Adaptor for C7 & D7 Valves​

Thanks - link doesn't work though.

 

[Plum]

Yes I do that and it inflates no problem - but it doesn't return to the locked position when I remove the pump and the air shoots out before I can close it.

then the one-way valve is faulty. Or, when you remove the pump, do you have an adapter that remains in the tender valve? Some adapters have a little piece of plastic in them that retains the one-way-valve in the open position.

Also, when you say "before I can close it", how are you closing it?

 

[andsarkit]

This is the fitting you want. Note the centre spring to hold the valve open.
C7 adaptor

 

[RogerFoxTerrier]

This is the fitting you want. Note the centre spring to hold the valve open.
C7 adaptor
View attachment 195820

Yeah they look good - looks like the coil will rotate and pull / push...