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CPS 2500 Pumping Question

Posted: Tue Jul 15, 2014 1:39 pm
by losty1
I just bought a 2500 and it is working good, but it takes about 50-60 pumps for the pressure to get full. The pressure holds, but I thought it was only supposed to take around 20-25 pumps. Is that normal? If there is anything wrong, what can be done to fix it. Thank you for any help you can provide.

Re: CPS 2500 Pumping Question

Posted: Tue Jul 15, 2014 3:44 pm
by DX
Check your pump seal, it may be worn out. If it's not sealing 100%, it's not moving as much water as it normally would per stroke. If the seal is fine, then check the tubing between the pump and the reservoir, there might be something jammed in there that is reducing water flow to the pump.

Re: CPS 2500 Pumping Question

Posted: Tue Jul 15, 2014 5:55 pm
by HBWW
If the pump seal is failing, it would be leaking while pumping (typically by squirting after pulling the pump forwards). I think the issue may be a leaky check valve letting water back to the reservoir when pumping. Does the pump bounce around a lot and/or otherwise behave oddly when in use?

Re: CPS 2500 Pumping Question

Posted: Tue Jul 15, 2014 7:29 pm
by losty1
Update:

It never leaked when I pumped, but sometimes it was weird. Sometimes it would feel like it was getting a lot and other times it was almost effortless pumping. That was before I decided to test it out again. I pumped it full and shot it and now it is not holding pressure. Water is coming out of the nozzle every time I pump. I am still able to shoot it and have more water come out, but it is not building pressure. Thank you for any help you can provide.

Re: CPS 2500 Pumping Question

Posted: Tue Jul 15, 2014 7:56 pm
by HBWW
(Same as my PM reply.)

The problem here is that the trigger valve is leaking or stuck open. There are a number of possible remedies or solutions for this, from adding silicone lube and rubber bands (that assist in the valve staying shut), to opening the valve itself and replacing the rubber seals inside.

For lube, add it to the valve where the pin goes into the internals. Make sure you use something friendly for plastic, rubber, and metal, such as silicone lube. (Never use something like WD-40.) For rubber bands, wrap them around the pin and valve, and they should help hold it shut. Don't use rubber bands that exert too much pressure, and use 2 of them to even out the force (one band wraps below the nozzle and the other wraps over it). I recommend that so the force is exerted more evenly, which might help it last longer in the future.

Re: CPS 2500 Pumping Question

Posted: Tue Jul 15, 2014 8:20 pm
by losty1
Update:

I opened up the firing valve and the rubber seal was off. I'm guessing that is why I was having problems.

Re: CPS 2500 Pumping Question

Posted: Thu Jul 17, 2014 4:20 pm
by HBWW
Next step is to just measure out the rubber seal you need and shop around. Unfortunately, I don't have measurements for it. Once you find the measurements, the best places to look are local hardware stores (preferably one well stocked with this sort of stuff) or home improvement. You can also look on McMaster Carr.

Re: CPS 2500 Pumping Question

Posted: Thu Jul 17, 2014 10:22 pm
by losty1
The rubber seal fell off, but it was still present. I epoxied it back on, but I am having problems once I close the firing valve. I am not able to release the water with the trigger. I am not even able to pull the pin back with my hand. The water ends up just staying in the firing valve.

The trigger and firing pin seem to work fine before I connect the two half of firing valve. The firing pin moves back and forth, but it seems like it pushes back as far it it can when I connect the two halves (therefore it is permanently sealed).

Re: CPS 2500 Pumping Question

Posted: Sat Jul 19, 2014 10:21 am
by HBWW
You should always be able to pull the pin back, no matter what. However, it's been a known issue for some CPS's where the firing valve gets stuck closed, but I've never encountered this on anything but my CPS 1000.

Try using more force. Does the valve get stuck closed even from just a few pumps?

Re: CPS 2500 Pumping Question

Posted: Sat Jul 19, 2014 12:47 pm
by soakinader
You need a bit of mechanical advantage to pull the firing pin. Thus, the lever. I know it's not easy but I have been able to pull the pin out with my hand on every CPS gun I've worked on.
Take a look at this post:
http://www.waterwar.net/site_wwn/board/topic6265.html
Read through it, especially the paragraph below the trigger picture. See if that describes your problem.

I just had a thought: When you had the firing valve OPEN, you should be able to push the part with the rubber seal into the back half of the firing valve. When it is closed (but not pressurized) you should be able to pull the pin back at least 1/4", and most importantly you should be able to hear the valve opening (or not).

Re: CPS 2500 Pumping Question

Posted: Mon Jul 21, 2014 7:48 pm
by losty1
The pin was able to go farther back. I'm not sure why I was having problems but I guess it was jammed. I applied some silicon spray and everything seems to be fine with the firing mechanism

So now I am back to my original problem. It is still taking about 50-60 pumps for the pressure to completely fill. There are no water leaks anywhere. It does not seem like water is getting let back into the reservoir when I pump, but I have noticed that it does not seem to move a lot of water on some pump (sometimes there is quite a few air bubbles). I haven't worked with a fully functional super soaker so I am not sure what is normal or not. Also the pressure holds in tube. It just takes a long time for it to fill completely.

Re: CPS 2500 Pumping Question

Posted: Wed Jul 23, 2014 10:40 pm
by soakinader
OK so this could be cause by a leaky OPRV or a bad pump seal. Check the pump seal and see if it is loose.