How Can This Happen?

[sjs]

Recently got my first PCP, an Air Arms T200 with an Air Venturi Hill MK4 pump. I also got the correct adapter. 

I tried to pump up the gun cylinder, for 3 days. It never registered on the pump air gauge. The needle would bounce with each pump but never go past zero. I have pumped over a thousand times by now. Fast and slow, pausing at the top and the bottom and not pausing. Only 50 pumps at a time with a rest to cool in between. A few times I pumped more than 50 times just to see what would happen and the pump get warm, but never hot and the resistance never increased. I called Air Gun Depot and the tech confirmed I had it all assembled and connected right.

It does have resistance when pumping but it never increases. I got the cylinder gauge up to 120 bar but it simply will not go higher. The gun is supposed to be up to 170 bar.

How can it work enough to get 120 bar and not anymore?

If the gauge on the cylinder is incorrect, how can I keep pumping but the reistance never gets harder?

How can the rifle cylinder gauge work to 120 but no farther?

How can the rifle cylinder gauge work that much but the pump gauge does not register at all?

Is there some secret to this?

 

[Keyman62421]

Is it possible that is the output max on your pump?

Sorry, had to come back with an observation. In my airgun pumping experience, you might need more ooomph,

 

[sjs]

No, it is rated to 4900 psi.

 

[shamu]

Did you cock your gun first to reset the valve?

 

[airgunfans]

It appears that you have a leak somewhere along the path from the pump's outlet to the filling port of the rifle's air tube. Are you sure that the bleed valve on the pump is fully closed ?

The pump must be giving out some compressed air or the rifle's gauge won't show any reading. There is a one-way valve just behind the filling port of the rifle's air tube so once air gets inside, the air will be trapped so the pressure can be buit up. However, there is no such thing in the hose / connectors / adaptors so the air in the hose can fully escape if there is a leak and the gauge on the pump will not show any steady non-zero reading. I am sure the guage on the pump did jump up momentarily in the down stroke or air couldn't have been moved into the air tube.

Apply some soapy water to the bleed valve of the pump and all connection points between the pump to the rifle's air tube. Check where bubbles come out as you pump. That's the point of leakage. My Air Arms FTP 900's leakage point is between the filling probe and the connector of the hose of my Hill Mk3 pump. The two parts have a conical mating face and it turns out that the angle of the cone on the two sides are slight different so it didn't seal up. I solved it by doing a little machining of the filling probe with my lathe. 

 

[jking]

It sounds like the pump is bad to me. If the gun has 120bar in it then the pump should have some resistance and I'd think the guns gauge would increase pretty easily as small as the cylinder is. Did you put the 120bar in the gun or did it come that way?

Is there a chance the gun has a regulator in it and it's set at 120bar? Sorry I can't give you a definite answer.

Jking

 

[sjs]

I did not notice the cylinder gauge reading until after I called the tech, so it is possible the gun came that way. I will try the soapy water idea this morning.

 

[JWilson]

Sounds like the bleed valve on the pump is not seated to me. I would remove, clean and inspect for abnormalities.

Just saw airgunfan’s post. Try that

 

[airgunfans]

I did not notice the cylinder gauge reading until after I called the tech, so it is possible the gun came that way. I will try the soapy water idea this morning.

To check whether the pump is working OK, you can plug up the outlet with a dead head and see if the gauge of the pump shows a steady increase in reading.

 

[RM100GUY]

PM sent.

 

[sjs]

Sorry to be so dense but what is a dead head?

I can feel air coming out when I loosen the bleed valve on the pump or on the adapter, and when disconnected I can feel it coming out when I stroke the handle so it does pump air. Just not enough perhaps. Cannot see how it is possible for the gauges on both the rifle and the pump to be bad.

I am not handy but I am going to look for a u tube video on how to disassemble the bleed valve, after I try to do it on my own without instruction.

 

[airgunfans]

Sorry to be so dense but what is a dead head?

I can feel air coming out when I loosen the bleed valve on the pump or on the adapter, and when disconnected I can feel it coming out when I stroke the handle so it does pump air. Just not enough perhaps. Cannot see how it is possible for the gauges on both the rifle and the pump to be bad.

I am not handy but I am going to look for a u tube video on how to disassemble the bleed valve, after I try to do it on my own without instruction.

A dead head is a plug like this :https://midlandmetal.com/item_detail.php?item=9522H2. You may use it to seal off the outlet of the pump in order to check whether the pump can build pressure. Usually plugs of this kind come with a rubber seal just beneath the head. If it doesn't , add the sealing washer shown in the photo below before screwing the plug in. The thread on the outlet of the pump is most likely 1/8 BSPP but I am not sure. 

Hill pump is well known for it's good quality so at this stage I won't suspect that it's faulty. There is no point to disassemble it before the problem point is located. 

 

[jking]

SJS, can you hear any leaking at all? Also be sure and apply some heavily soaped water to all the fittings and look for leaks. It don't take much of a leak even on a 110 volt compressor to kill the performance of the air compressor. Do you know if there is anyone in your area that might be of assistance? Probably something simple so don't get discouraged.

Jimmy

 

[bucketboy]

 If you are able remove the hammer spring, lock the bolt forwards, place a balloon over the barrel and give a few pumps, if the balloon inflates then the valve is not sealing correctly, it might need a quick blast from a divers bottle to seat it, then pumping should work.



Bb

 

[jking]

Bucketboy, I think the guns cylinder has 120bar in it if I'm reading the original post correctly.

JK

 

[bucketboy]

Bucketboy, I think the guns cylinder has 120bar in it if I'm reading the original post correctly.

JK

Oops, I didn’t notice that, I must have scrolled up a bit too far when I read the post.



bb

 

[sjs]

I put a rubber glove on the outlet and the pump inflated it but did not have enough psi to burst it. I am new to this but I'm going to guess that is not enough pressure to fill a cylinder even partially. 

The gun must have come with 120 in the cylinder. I am returning this if air gun depot will let me and getting a Benjamin Pump instead.

 

[John "spysir" Blount]

 If it is a hand pump issue and you must purchase another you might be well served to pop on over to the air compressor & tank & such section of the forum and glance at the sub-$100 hand pumps.



John

 

[sjs]

I submitted a question to the English maker of the Hill pump and am awaiting their response. Meanwhile, I am postponing a return of the pump, though I have the clearance to return it if I need to. I followed the advice given here and also went over it with an aircraft mechanic friend and I think the pump might just be fine. It may just be an adapter issue.

I looked at the "PCP Hookup" section on the PA website, then talked to their Chat tech on line, then called and talked to a tech and then called the Airgun Depot folks twice and could not get any consensus on exactly what adapter was needed for my rifle. So, I ended up ordering two different ones to be safe. I now think that neither one actually fits the pump fitting properly and air is leaking out at that fitting. I have a third adapter on order now after talking to AG Depot again. I might get lucky this time but in case I don't, I thought I would just ask here.

Does anyone actually own an Air Arms T200 rifle and a Hill MK4 pump? 

If so, what adapter(s) do you use?

Should I ask this on a different sub-forum?

 

[airgunfans]

If you can post some pictures of the adapters and connectors showing the mating face shape, it may help us to tell whether the adaptors are of the right type.