Pressure Problem

HighTide

HighTide

New member
I have been having pressure problems for over a month now. I have 18 hp Vanguard with TS-2021 pump with vertical hot box. Specs new were 3,500 psi @5.6 gpm. I have a one-year old green spring unloader on this unit. I can operate at 2,700 psi that spikes to 3,500. If I turn unloader up to 3,000 psi, it will spike to 4,100 (and bust my 4,000 psi hose after few hours of work). Today, I replaced the unloader with a new Allison Soft Touch from Envirospec. When adjusting for first time, it started at 1500 spiking to 1600. Turned it up to 2000, which now spikes to 2500. Turned it up again to 2700 and it now spikes to 3500. It seems both unloaders provides similar pressure issues. I was also told that this new flow type unloader would not "spike." Note: I used several type of new 2506 nozzles using only 100 ft of hose and bypassing my hot box. I also used an older pressure gauge at end of 100 ft of hose as well as a brand new gauge (in case my gauge was bad) all showing same reading.

My pump filled a 5 gallon pail in 50 seconds so I am getting the correct gpm at 5.6 gpm and there are no air leaks in system and no water leaks around pump. Just changed oil in pump. Also changed oil, oil filter, plugs and air filter on my Vanguard.

I have no problem cleaning a house with low pressure. But I have a terrible time cleaning concrete since my max psi is 2,700. Do I need to rebuilt my pump or just buy a new one? My local guy charges $300 for a pump rebuild and I can get a new pump delivered for $450 plus installation.

After saying all this, am I missing something? Or is this a pump issue? The pump is two years old and has never been rebuilt (but only heavily used in last 6 months as I didn't do a lot of business in my first year). I have never adjusted my Vanguard's rpm but it seems to be running correctly (I wouldn't know how to adjust this) and there is no throttle on this unit (just on or off with a choke). If this was your setup, what would you guys do next? Rebuild? Buy new pump? Buy different pump? Or something else? Thanks for any advice!
 
Is your gauge on the head of the pump or the coil outlet? If it's at the outlet, you could have a scale build-up that would use up some of the pressure before it gets out of the coil, hence only running 2,700 psi. When the unloader bypasses, you'll see the total system pressure spike, scale or no scale.

If you use an undersized injector to pull soap through long lengths of hose, and the gauge is mounted downstream of the injector, you can see the same result.

Or, the pump may need rebuilding. It's pretty simple if you pay attention to how it comes apart.

You mentioned changing the oil...was it milky?
 
Russ, the coil and injector were by-passed. Pressure gauge was at the end of a 100 foot hose connected directly to new unloader. Pump oil was not milky when changed (it didn't even look that dirty). Thanks.
 
I assume you did the flow test with no nozzle / gun. At negligible head pressure, even good sized internal leaks would not show up. If, however, you have damaged packings or check valve o rings, the reduced flow would show up under pressure.

Are the belts good and tight? Slipping belts will also cause the flow to drop off under pressure.
 
The belts are tight and the flow test was with no gun or nozzles. I guess I will look into pump rebuild after Labor Day. Thanks!
 
You must log in or register to reply here.
Back
Top