Unloader - over pressure, no flow

[810f250]

Yes, yes, yes, all that, ..and a cup of tea, Eh?
It's great to see you guys thinking this all through, so..

The moral to the story..

A) Get a pressure gauge on the head of the pump,
and at the hose reel..
the first one tells you the performance of the pump system,
the other tells you the flow restriction thru the coil, and the actual spike-pressure against the outlet side of the system,
including "water-weight" (aka inertia) in that more-than 50 ft hose you have.
Don't leave more than 150 ft of hose on your reel for that reason, and the reel will last longer too.

B) you need actual, methodical, proven "Guidelines" for adjusting an unloader valve SAFELY and for long-term-low-cost.
e-mail me for FREE copy of that info.

C) when you check system pressure, use your O-degree nozzle,
as it is more accurate, since it has a more durable oriface.
Your worn nozzles are a problem to the reliability of system components..
If you adjust that unloader "perfectly" with a good nozzle,
when you use the worn nozzle, you won't have as good a working-pressure as possible,
and you won't be bypassing as much as the unloader needs to for long wear, and lower pressure-spikes.
It's better to go down a nozzle-size to bypass a little water, and enjoy a better working pressure,
than to "flow the whole flow" with reduced pressure, and the unloader hammering itself to death.
e-mail me for a copy of the "Nozzle chart" and learn how to use it ACCURATELY

D) More and more of you guys are going over the recommended 7gpm max through 3/8" hose..
the flow restriction is horrendous.. 5gpm through a 100ft hose sees about a 130psi drop..
Put 8gpm through 3/8" hose and loose 300+psi for every 100 ft.. that's right,
in 200ft, you may see 3600psi at the pump, but it drops to barely 3000psi at the wand.
If you use 1/2" hose, you would have 3440psi at the wand..
only 80psi drop per hundred !
So while you're having to scrape gum, the guy that has the first 200ft in 1/2" hose, and the last 50ft in 3/8"..
he can blast the gum away, without bending over a scraper. ..at 250ft.
e-mail me for a copy of the "restriction-to flow" chart.


E) What !? no mention of the Pressure relief valve, that should have spewed at 4300psi on the 3600psi system !?? Aaarg !
:slap:

RESPECT the tech !!
CALL for more info.
we aim to be your favorite supplier. :dirol:

Great info Jerry, I have upset the manufacturers equlibrium of my setup. I was also wondering if the relief valve would ever pop.

 

[Sirocco Jerry]

regulating relief valves

Again I have to say, what a great thread !! ..one of the most important to read for newbies coming in. Eh?
Good job guys ! ....:clapping:

About pressure relief (safety valves)...
I mentioned the huge spikes caused by long hoses..
and I've mentioned reliability in Relief valves..
I have to add..
a "Regulating-Relief" valve is WAY more accurate than a pop-off..
On more sensitive systems, like the ones with steam options, or any running over 200deg.F
I like to use the regulating relief, as you can adjust it for a much tighter (..more accurate) setting..
the Adams style 7400 series go to 3500psi and are my favorite... rebuld it with two 0-rings.
the VS220 by "PA" does 3600psi,
VS350 goes to 5100psi ..very accurately.
you can also take a blue or black-spring unloader andremove the outlet check-valve
to use it s a relief.
note: If you have a "pressure-actuated" unloader valve, you MUST have
a relief on the head of the pump, AND a relief on the inlet of the heater system to protect the heater coil. Eh?
only the very BEST (safest, reliable) machines in the world have 'em from the factory.
I'm STILL trying to get a manufacturer to make an affordable (mass-produced) Flow-actuated unloader
for up to 5000psi (reliable on 4000psi) . Only one relief is necessary on the system,
..and failures are MUCH less traumatic on the system.
which reminds me..
that K7 with the big spike-pressure..
must be from the "long hose syndrome"..
as all that water in the line smashes-into the trigger-valve, swells-up that long hose, and
the regulator reacts to the spike it sees at the pump, the "bubble" of water-surge at the gun bounces back
against the heater coil and the unloader, a "greater than expeted" spike pressure occurs.
I've seen spike pressures as high as 1000psi over the working pressure at the hose-reel,
where there is normally almost no spike on flow-version unloaders. ccheck it out !..
put a gauge on your hose reel, and compare it to the pressure at the pump..
KNOW what your system is actually going through..
this will explain why you go through QC o-rings every day, outlet check-valves on the unloaders fail every 6 to 9 months, etc.
I could go on, and on.