# How do I fix a leaky check valve?



## afinegan (Jan 2, 2008)

How would I go by fixing this leaky check valve. I steamed up the DJB coal fired boiler 2x now and it works good except I have a small leak out the intake pipe for the water pump. I opened the check valve and looked at the ball and where it seats itself. I think that might be where my problem is. Dont worry about my technical experience, im here to learn so hit me with what has to be done to properly fix this rightly.


Other than that, im excited to have this project! When I got the blower going, this thing came ALIVE (blower overpowers my draft fan). Made my butane ruby hide in the corner.


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## weaverc (Jan 2, 2008)

My recommendation is that you contact David Bailey directly at:

[email protected]

David is a very nice man to work with.
http://www.noradsanta.org/


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## Steve Shyvers (Jan 2, 2008)

Andrew, 

Why don't you contact David Bailey by email and ask for his recommendations? He posts on MLS. If he reads this thread he might post a reply anyway, but no harm to ask. Although there is a common method used to form ball check valve seats, I would definitely find out what David's recommendations are first. 

My guess is that the water pump has two internal ball check valves as well, so there are three possible check valves to leak. Is the leak a steady stream of water or successive drips? I confess that my experience with ball check valves is minimal. Might be that a slow drip is typical for this type of simple valve. 

Steve


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## Pete Thornton (Jan 2, 2008)

the ball and where it seats itself 


I'm sure the official experts will be jumping in soon, but let me say that re-seating a ball valve like that is often done with brass polish. Apply it liberally to the sreat and rub the stanless ball into the seat.


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## Nick Jr (Jan 2, 2008)

Pete, can I assume that will work with pressure relief valves also??? Nick Jr


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## David BaileyK27 (Jan 2, 2008)

I would not use any pollish or grinding paste on valve seats or balls, to start with I would pump water through the system by fitting your pump bottle to the pump water inlet pipe and pumping water into the boiler, this will flush out any dirt which maybe hilding the balls open, you will have to close the by-pass for this operation otherwise the water will come back out of the by-pass pipe. 
You do not say if there is water coming out of the inlet pipe when the engine is in steam or not 
If the leak still pesist then it could be any one of the ball seats leaking, I would not take the pump to pieces unless you have experience of servicing this type of pump, as a last resort remove the pump and send it back to me. 
David Bailey www.djbengineering.co.uk


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## afinegan (Jan 2, 2008)

Thanks all for your quick replys, 

water does not come out when it is sitting in place but once the boiler has pressure, it leaks water droplets slowly 
when the pressure increases, so does the leak. It is leaking out the intake pipe. 

Tommorrow I will pump water thought the inlet pipe to try and clean off any debris that might be in there. 

david, I will keep you updated. everything else on this boiler is top working order! 
can't shutup about it around my family :-D 

andrew


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## Semper Vaporo (Jan 2, 2008)

Posted By afinegan on 12/24/2008 7:33 PM
Thanks all for your quick replys, 

water does not come out when it is sitting in place but once the boiler has pressure, it leaks water droplets slowly 
when the pressure increases, so does the leak. It is leaking out the intake pipe. 

Tommorrow I will pump water thought the inlet pipe to try and clean off any debris that might be in there. 

david, I will keep you updated. everything else on this boiler is top working order! 
can't shutup about it around my family :-D 

andrew 




These little ball check-valves are well noted for leaking. 

The "ideal" fix is to get TWO new balls of the same size, remove the valve from the boiler (you don't want to do this with it still attached to the boiler shell), remove the old ball, clean the valve seat, insert one of the new balls and using a short wood or brass rod and a small hammer whack the ball against the seat in the valve body. Then replace the whacked ball with the other new one and put the valve back on the boiler.

Another fix is to use a "Nitril" (high-temp rubber?) ball, they have some flexibility and seal a bit better over an uneven seat.

EDIT: I should also note that sometimes they will leak for only a while, while the boiler is heating and will seal up after the temperature stabilizes.


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## David BaileyK27 (Jan 2, 2008)

It depends on which Clack valve you have, I fit Clack valves with an O ring Shuttle valve so there is no ball to seat, the O ring seat may leak slightly when cold as it tends to "float" off its seat, but will shut with steam pressure behind it, same goes for the pump valves but they are ball valves, they were seated and tested when they left our workshop, I test water pumps up to 200 PSI which is more that enough to ensure the balls seat OK. 
Everything should settle down when you run the loco so I would not worry unduly about these small leaks now, only if they get worse during running. 
Have a Happy Xmas 
David and Paul bailey ww.djbengineering.co.uk


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## Ed Hume (Jan 3, 2008)

If you have an ultrasonic bath they are excellent for cleaning in general and they can do a good job with valve parts. Small ones are sold for cleaning jewelry and eye glasses - Micro-Mark carries them. I use mine often to degrease parts before silver soldering or painting - the ultrasonic action even cleans out blind tapped holes.


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## afinegan (Jan 2, 2008)

Hey all,

I fixed it, some dirt got in where the check valve was, I opened the top and dropped the ball out and stuck a cue tip in there and spun in. The cue tip had some brown dirt/something else on it. After I did this I put everything back (little dab of silicon on the screw threads) and put it back together. Hooked it up to an air compressor (40 psi) and the leak was gone. Then I put the water intake portion of the pump into water and opened the bypass and let it prime up with water, closed the bypass and watched as the sight glass filled up.

Since everything worked so well, I took the engine to my dads track in the backyard(still up as his house) and fired it up. Since I have the wrong coal it would build up steam fast then the coal would burn out (pocahantus coal from my local 7.5 gauge track). Here is the results (in the dark mind you).







2 times around on the first run, not too shabby, waiting on my shipment of welsh coal, I think that will be the winning ticket! Thanks for all your replies


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## David BaileyK27 (Jan 2, 2008)

I would not run it again without the water supply hooked up, it is very easy to drop the water level below the crownsheet and then you could burn the copper, it needs to have the pump running most of the time to keep the water level up. 
Good Steaming 
David Bailey www.djbengineering.co.uk


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## afinegan (Jan 2, 2008)

Working on the water supply right now (mimi tender), I was topping it off with the goodall valve at this moment but rather do it the right way.


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