I hate the Hand Pump ! ! !

Saving my shoulder, replace the hand pump. 

The STW Hand Pump is a backup device.  You have to have a way to get water into the boiler if the level drops too far and trips the safety shutdown.  After driving the Lyka for a year (60 miles total) I have been studying how the water level moves during driving, how it changes after being parked hot, and what happens if you play and interrupt the natural physics of the boiler and steam system. 

But the hand pump is very slow to fill the boiler.  There is a handle provided that attaches to the pump.  You have to stroke it up and down, netting an unknown amount with each stroke.  It takes a real long time to get any level change in the sight glass, and frankly, my shoulder gets very upset after about 5 minutes. 

I was watching Jay Leno work on his Stanley Vanderbilt Racer where he was explaining the startup procedure and made the statement that they replaced the hand pump on the Vanderbilt with an electric pump to top off the boiler if needed.  I figured that if Jay could do that, I could too!

 

Here is the hand pump installed and plumbed into the feedwater system. 

 

 I came up with a number of criteria for the replacement pump:

• 3/8" NPT fittings
• 12 volt DC power
• 200 PSI max pressure
• capable of running dry
• reasonable amperage use
• fit into the space near the hand pump location

 

 

This is the model I chose.  About $125USD

 

Test placement.  Might be tight.

I chose to mount the pump to a piece of 1/8" plate, the unit comes with rubber feet and you screw thru them to give yourself a shock absorbed deal.  I also added the following items to the assembly:

• 12 V automotive relay w/socket.
• inline fuse holder / 20A fuse.
• barrier strip for connections
• SPST switch to be mounted next to sight glass in engine compartment. 
• 2 - 3/8 NPT M/F close elbows - brass. 
• 2 - 3/8 NPT x 12" high pressure braided pigtails (3/8"NPT M each end) 
• 1 - 3/8 NPT F - 3/8 Compression adapter.
• 1 - 3/8 inline check valve - 2PSI differential - 3/8"NPT F/F
• 1 - 3/8 NPT M - 3/8 Compression adapter. 
• High temp (plenum) 2 cond cable for hookup - 18ga for switch, 10ga for main power.
• cable cover (woven black) cause I want things to look old. 

I tapped into one of the positive battery connection points and my ground buss bar up under the floor. That cable ran along the top of the frame near the tabs for the fuel tank and then snaked back along the outside of the left hand water tank. 

The switch is installed in the frame over by the sight glass.  I do not use the engine cover at this point, so it's placement is not an issue.  In the future I may move it to a more obscure position. 

After removing the hand pump, I used the bracket to mount the plate. Then routed the flex hoses thru the available holes to meet up with the 3/8" tubing in the hand pump circuit.  I cut the tubing to length and attached via the compression ends.  All NPT threads were sealed with Rectorseal#5 and I added teflon string to the brass elbows as they threaded pretty deep.  

Here is the resulting assembly with the inlet flex tube coming up thru the hole in the hand pump bracket and the outlet flex tube leaving via the space between the frame and the back wall.  All electrical connections are at the back of the pump. The relay is hidden under the fuse holder. Everything is sealed in shrink tubing after crimping.  

 

A view from the back, the inlet pipe is on the left, the outlet on the right.

 

A look from the side. 

 

It is hard to see but there is a 3/8" check valve in line on the output.  I chose to do this because I was seeing some anomalies on the hand pump that indicated there was backwards pressure in the system and the little ball bearings were not always stopping it.  Most of the time after a run, I would find the handle of the hand pump in the "fully extended" position.  This indicated to me that pressure had been applied to force the piston out.  I would move the handle back to the mid position, and it would be forced out each time.  Since this is feedwater, the temperature was basically ambient, so just pressure was involved.  The pump has an automatic cutoff at 200PSI, that will keep me from overtaxing the system.  

 

A lonely hand pump

 

SYSTEM TESTS 

I flipped the switch, the pump whirred, nothing came out.  I went inside, had a pee, sat and pondered a moment.  I disconnected the two compression connections and put the inlet in a bucket of water, nothing.  I went to the outlet - I could feel some slight pressure against my finger, but nothing else. 

I stuck the out tube in my mouth and sucked - EUREKA - a mouthful of bucket water - and it kept on coming.   I know there are chambers and diaphragms in the pump head, so I am guessing that they were dry and sealed up.  Just needed a priming to get the juices flowing. 

Of course each time I played with the plumbing I needed to drain and fill the tanks, so I hooked everything back up, checked for drips, refilled the tanks some more and did my first test. 

Test #1 - no pressure. 

I drained the boiler to just above the cutoff sensor, then ran the pump while manipulating the feed valve lever. 

 

 Test #2 - under medium pressure - 120PSI.

This test simulates the situation where you have run the water level low and cut-off the burner but for some reason the engine-driven pumps are not doing it for you.  You pull over and park, turn the pump on and manipulate the feed lever to fill her back up. 

Watch the video - I will discuss it after.

 So here is what I saw - 

1. The water level was late in starting to change.  I think this is because the "bubble" was trapped so I did not see the fill happening until late.  
2. I played with the bypass lever, should have moved it the closed and stayed there.  I was working from ear, waiting for the same clack I get while driving and pumping.  I did not hear that, I heard a "rattle".  The rattle was occurring as the bypass was opening and closing.  One closed, the pumping action "flow rate" was enough to keep the check valve open, so we do not hear the "clack".
3. Once the bubble moved, and I stopped playing with the bypass, the pump did its work and filled the boiler back up. 

Notes: My check valve is a mechanical flapper (brass) and gives a noticeable "clack" when opening and closing against the engine-pump action.  It would appear that the pulses in the flow allow the valve to close between pumps.   The electric pump is much more continuous, reducing the clacks except when opening and closing. 

I will continue to play with scenarios and push the pressure up to test limits. 

The end result is that I now have an electric pump and my shoulders are grateful. 

Thanks for reading - 

Jim

poppapope

Denver, CO USA