Pressure setting

[Andy Burn]

Currently I am running 1100 psi pressure to the bays and using winter weep guns. However, some customers have complained that the pressure is not enough. What is considered an optimal pressure? Please advise.

 

[OurTown]

We are running only 1,000 psi and get compliments quite often that we have great pressure. Maybe you have corrosion somewhere restricting flow. What size tip are you using on the wands? We are using a 2507.

 

[Roz]

We are running only 1,000 psi and get compliments quite often that we have great pressure. Maybe you have corrosion somewhere restricting flow. What size tip are you using on the wands? We are using a 2507.

Tip size is often the issue as it can restrict the water volume through the nozzle, 2507 is a good size or even a 2508 (what we use). Other thing to check, when someone pulls the trigger see how much of a pressure drop you see on the gauge. Should only be about 200PSI. You can increase the PSI from 1100 to 1200 (we use 1250). If hoses are several years old you may have crud (from the water) built up inside the lines and consider installing new HP lines (not expensive).

 

[cantbreak80]

Humans often mistake volume for pressure. It’s the fire hose effect. Say the fire apparatus can pump 300 GPM @ 150 PSI. Crack open the fire hose nozzle and a single firefighter can handle the hose. Now, fully open the nozzle and that firefighter will need several buddies to help hold on to the hose.

Operating at 1,000 PSI a new #5 spray tip will deliver 2.8 GPM.
#6 tips provide 3.0 GPM
#7 tips provide 3.5 GPM

Increase the pressure to 1,200 PSI and…
#5 = 3.1 GPM
#6 = 3.3 GPM (Most commonly used in my market)
#7 = 3.8 GPM (Starts to become difficult and tiring for some customers)

I once visited an operator who ran 800 PSI. His wands with a little bend at the tip. Why?
"It pushes the tip up when they pull the trigger...folks think I'm running better pressure."

 

[PaulLovesJamie]

You are running 1100 psi at the pump, not at the bay/tip. So although the responses about tips are true and correct, it is misleading because you do not have 1100 at the tip. Measure the pressure at the tip. Also note that the length of the hose will effect the pressure drop, so all of your bays are probably not the same.

I use a 2506, 1150 to 1200 measured at the tip. cantbreak80 wisely points out that if you try to please the customers who want more pressure, increasing it too much will be difficult and tiring for other customers, you need to balance that for your demographics. Yes, at 1200 some of my customers complain that it is a tiring.

 

[Andy Burn]

Thank you for your help. The installed nozzles are 1/8 MEG 3207. So as I am weeping water, should I go with 2506, 2507 or 2508? Regards Andy

 

[Roz]

Thank you for your help. The installed nozzles are 1/8 MEG 3207. So as I am weeping water, should I go with 2506, 2507 or 2508? Regards Andy

So you have a wider spread. I know operators who use a 1506 to have a narrow spread so people think the nozzle is giving them more power. At end of the day comment above is right, find a balance and never try to please 100% as that is an impossible goal. Good luck.

 

[OurTown]

Thank you for your help. The installed nozzles are 1/8 MEG 3207. So as I am weeping water, should I go with 2506, 2507 or 2508? Regards Andy

32 degrees is too wide of a pattern IMHO.

 

[cantbreak80]

[Flame Suit ON]
IMHO, 15-25° patterns are just too narrow for self-serve. While I’ve run 40° for years, I now recommend the 32° pattern nozzles… provides good coverage for the customer and speeds up bay floor cleaning for the attendant.

Regarding Andy's weep flow rate question:

The nozzle’s degree pattern has nothing to do with flow rate.
Spraying Systems nozzle ratings are based on 40 PSI, so…

A #7 tip flows 0.7 GPM @ 40 PSI (regardless of the spray pattern.)

A #6 tip flows 0.6 GPM @ 40 PSI

If your weep system flow meters/valves are wide open AND your weep system water supply operating pressure is set at 40 PSI, you’ll be weeping at 0 .7 GPM per nozzle.

 

[Randy]

We set our Cat 310 pumps at 1500psi and use a 1505 nozzle, we've tried a wider nozzle but our customers didn’t like them so we went back to the 1505.

 

[soapy]

I like a 15 degree nozzle also and use 1508s, For every 25% more water you double the impingement at the same given pressure. A narrower nozzle will focus the impact better and keep its impingement farther from the tip.

 

[MEP001]

I run 25055 at 1300 PSI. The city doesn't allow car washes to exceed 3 GPM, so when they come around to check I turn the pressure down a bit, then I turn it back up when they're gone. IMO 15° is too narrow. The Kleen-Rite "perfect nozzle" is 32° MEG nozzle, which I think is too dangerous to put in people's hands.

There's a distributor in San Antonio who sells wands with a bend in them so it feels like more pressure. Some operators only run 600-700 PSI with an 06 tip because that bend makes it almost impossible to hold the gun at a normal 1000 PSI.

 

[washnvac]

I bought a wash that the operator had that bend in the wand ends. He was running barely running 750 psi. It sucked at cleaning, and I personally did not like fighting the wand to keep in place; therefore I know my customers would not like it. I changed all those in short order.

We run 25055 tips @1250psi at the pump.

 

[GoBuckeyes]

You are running 1100 psi at the pump, not at the bay/tip. So although the responses about tips are true and correct, it is misleading because you do not have 1100 at the tip. Measure the pressure at the tip. Also note that the length of the hose will effect the pressure drop, so all of your bays are probably not the same.

He's exactly right. Put a Tee with the pressure gauge and a brand new tip (whatever size you decide on, we use 2507) in place of the tip in the bay. Have someone in the equipment room crank up the regulator until you get your bay pressure where you want it, then mark that bay's equipment room pressure gauge with a paint marker. Each bay will likely be a little higher the farther you get from the equipment room.

 

[James.Ireland]

I run 1200 psi with a 4006. Pumps are Wanner Engineering D10. Water is stupid expensive where I am but people seem happy with the volume and pressure. I get compliments weekly.