Graco Magnum Airless--rebuild?

[paredown]

I have an older Graco Magnum XR-9 that I used a lot for a time, and it then got back-burnered, since it seemed like all I was doing was small jobs, where it seemed so much easier to brush and roll. It was inside, and moved around, and outside in temporary storage in an HF tent.

Well I had a job where I wanted to use it--I was able to fire it up, pump out the storage fluid, prime and spray. cleared out some clogs in the tip, and it seemed fine.

Took it to the job, got all set up, came back the next day and could not get the machine to prime--or more accurately--it seemed as if it was holding prime, but not spraying at all--tip off, nothing. Ended up brushing and rolling multiple coats on a room full of panel doors (jeebus that's slow)--and brought the sprayer back to the house. Watched some Graco videos, and cleaned the inlet, removed and cleaned the ball (I'd already replaced the gun filter), hose seems clear, and still no joy.

Tomorrow's project is to fully take apart the gun and clean it, so jury is still out as to the root problem--but what I'm most worried about is the evidence of rust internally. I foolishly thought that the Pump Armor would protect the internals, but it seems like it did not (although this could be a function of the length of time it got left unused).

Any thoughts on how usable sprayer might be--even if it requires a pump rebuild?

 

[dnschmidt]

Out here in the West we have a paint store chain called Dunn-Edwards. They rebuild these pumps daily as their clientele are 90% professional painters. I let them screw with it. They know what they’re doing and I don’t.

 

[yatg]

By holding prime, do you mean that its sucking the up the big inlet tube and coming out the prime tube?

When you flip it to spray and turn up the pressure, are you getting any flow through the hose?
IIRC, if you remove the gun it should still pulse fluid through the hose.
You can just use water for testing.

 

[paredown]

By holding prime, do you mean that its sucking the up the big inlet tube and coming out the prime tube?

When you flip it to spray and turn up the pressure, are you getting any flow through the hose?
IIRC, if you remove the gun it should still pulse fluid through the hose.
You can just use water for testing.

It seems like it was pumping intermittently--turn up the pressure setting and the motor would start, but not build pressure. If you set it to the prime setting (pressure, and switch down) it would not start at all. Sunday, I took the gun completely apart--it was in surprisingly good condition--no evidence of damage or problems.

I was testing it with just water, since I could not get it to start when I had it set up to paint.

I talked to the Graco help desk today--and I have ordered a pump rebuild kit--they seemed to think what I was describing sounded like a pump problem.

 

[yatg]

Its been a few years since I've used my sprayer, an older XR9, but the principles are the same.

When the lever is in prime, it opens a bypass to the prime tube. The pump should run continuously on prime because the fluid is diverted back to the bucket and there's no pressure being built in the system. Yours doesn't seem to be doing that.

But when you turn up the pressure knob, the pump starts.

If its in spray mode with the gun connected, and you turn up the pressure knob and the pump starts to build pressure, does it ever shut off? It should. Then as you spray, it should run to keep the pressure up. When you stop spraying, it should run a few more cycles then stop.

Hopefully Graco is right, but it sounds more like your problem is on the electronic side, pressure knob or control board.

Here's a link to a manual that may be of help. There's some diagnostics you can try.

https://www.graco.com/content/dam/graco/tech_documents/manuals/312/312667/312667EN-L.pdf

 

[paredown]

Its been a few years since I've used my sprayer, an older XR9, but the principles are the same.

When the lever is in prime, it opens a bypass to the prime tube. The pump should run continuously on prime because the fluid is diverted back to the bucket and there's no pressure being built in the system. Yours doesn't seem to be doing that.

But when you turn up the pressure knob, the pump starts.

If its in spray mode with the gun connected, and you turn up the pressure knob and the pump starts to build pressure, does it ever shut off? It should. Then as you spray, it should run to keep the pressure up. When you stop spraying, it should run a few more cycles then stop.

Hopefully Graco is right, but it sounds more like your problem is on the electronic side, pressure knob or control board.

Here's a link to a manual that may be of help. There's some diagnostics you can try.

https://www.graco.com/content/dam/graco/tech_documents/manuals/312/312667/312667EN-L.pdf

Well it gets curiouser and curiouser. I did order the pump packing kit. Before installing I started the unit up, and it would not prime--only had slight drips out of the prime tube but at least the motor was running consistently (I thought)

Installed the pump kit--took a couple of tries to get everything lined up and buttoned up. Worked better on the prime, but not great. Rechecked the intake check valve, and made sure the ball was completely free (the trick seems to be to leave the plastic ball holder lose, and let it get pushed into place as the assembly is tightened--that seems to keep the ball assembly loose enough.) So then it primed, sprayed and held pressure.

At that point I tried to adjust the gun and stop small leaks (the o-ring on the bottom of the gun had disintegrated and what I tried to use didn't work--so I picked up something at the local hardware store--not perfect but better) Gun also leaked a little out of the tip, which suggests that it may need a rebuild (I had if completely apart to clean) and was careful with the packing/tip.

While fooling around with the gun, the sprayer started acting up again--basically not starting up to maintain pressure while spraying. So I at this point I thought I might have an electrical problem, because it was intermittent. This is more or less what happened when I took it to the job site last week--worked OK at home, wouldn't run consistently when I got set up on the job and finally would not start at all. Took off the plastic cover, checked connections. Board fuse was OK, no signs of burns on the traces etc. Tried jumping the switch--no joy--wouldn't prime or start up. At this point I'm thinking the control board has problems. Put the cover back on and have a think...

Then while I go to move the sprayer, it starts pumping again--and I figured out that if I tip the handle back on the cart the pump will start--let it drop forward, it cuts out. WTF??????

So the sprayer will prime with the cart tipped back (I put a 2x under the front of the legs), but now it doesn't seem to hold pressure consistently and continues to pump more than it used to (when working properly and you are spraying I used to get a nice little burst to maintain pressure every few minutes--now it is continuous.)

Looking at the front of the unit, I see small drips forming under the pressure switch--so there may be a leak there (AFAIK this is not serviceable). While it is pumping, I also see leakage out of the prime/waste tube... The only think left that I may be able to remove and clean is the prime/spray valve--it may be gunked up. (I'm mad at myself for not taking this apart when I had the pump assembly out.)
From manual: "Spray–Prime/Drain valve is leaking. Check Spray–Prime/Drain valve for debris trapped on seat and for worn parts. Torque to 185 in-lb (21 Nm). Replace if parts are worn."

If the pressure switch and prime/spray valve are damaged, I'd be looking at another $200 in parts for an almost 20 year old sprayer...

Sometimes DIY is not straight-forward!