flow but no pressure

duane t

duane t

New member
russ, i have an Alkota 5305 thats about 9 years old. 4 yrs ago i replaced the AR pump with a ts2021. a few weeks ago it had trouble building pressure. i bought a new pump a couple years ago so i put that on. everything was fine till today..it won't build pressure. i get a full flow wide open. i back off the unloader and the stream weakens then when i crank down the unloader the stream begins to gain strength but no more than a garden hose. i replaced the unloader with a rebuilt and still no pressure. i would appreciate any suggestions...besides throwing away the general pump. thank you, Duane
 
Could be trash in the valves.
Does the machine have a downstream injector?
Does the engine sound like it's working hard?
 
no downstream...engine is not working hard either thanks for the help
 
Pop the caps on the head, and check the valves for debris, then check the o-Rings at the base of the valves for wear. They should be round, and round.
 
good call Scott.
If the problem isn't there, check pressure AT the HEAD of the pump..
As Russ implies, flow-restriction could be the issue..
partially plugged coil,
flow switch could have come apart inside,
An unloader could have internal issues,
and a rebuilt one isn't a good unloader until it proves itself..
When you rebuild one.. test and adjust it, tag it "good" date, pressure & all.
Hopefully you have your unloader bypassing to the water tank,
so that's EASY to check.. If it bypasses when you open the gun
with the nozzle in, you have an unloader problem.
Remember..
Don't assume the worst,
Check the easiest stuff FIRST, (belts could be slipping !) :haha:
and don't delay the diagnosis..
there are NO discounts, at the local service-center
for "Last-Minute" repair services. Eh?

:slap:
 
This is one of those things that leave you scratching your head. I checked the valves, they were spotless. I opened the plug on the pump's high pressure side and it was making pressure. Coming off the pump there is a tee, the flow switch in one port. Then another tee, a jumper hose to the unloader and there was a fitting that reduced to 1/8 inch hosebarb. I swapped the 2nd tee for an ell and for some reason it's working fine. Thank you everyone for your help and suggestions.
 
You probably had too much restriction on the outlet of the unloaded. As the unloaded aged it is getting sensitive, made worse by the restriction. Your unloaded could be on the way out.
 
We like to kid that machines "think they are girls"..
as problems come and go like a mood..
But no,
they simply have bugs that are sometimes less or inactive,
..but the bug is there, until found and removed.
Not to be negative, I'm just sayin' keep an eye on it for the next symptom.
..And check it again, before starting a new job or demo.

Have you found any shiny-metal, or rubber-bits in the spray-nozzle lately ??
Did we establish a flow-actuated unloader is on that machine ??
a K-7 can get intermittant before it fails.
but they are also rebuildable. ..'til the main valve ball and seat get thrashed.
 
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