Cat 310 Pressure Loss

[Bubbles Galore]

Here's the situation:

I had a bay freeze up and its been frozen for a few days now (too much going on with the automatic to worry about it). I finally get around to thawing it out tonight and everything goes smoothly.

I open the bay back up and as soon as a customer kicks on one of the high pressure options, I know something is up (just by hearing it). I look at the pressure gauge and its only reading 900 psi while prior to the freeze up it was running steady at 1200. I change out the gauge and get the same results. Weird thing is that when the customer lets off the trigger, the pressure jumps up to around 1200 psi. I try to adjust the pressure regulator and nothing. I check each phase of the three phase and that's good. This is the bay right next to the equipment room and after the HP ran for 5+ minutes, there wasn't any water leaking from the boom in the bay or in the equipment room...

Any suggestions where to look next?

 

[Eric H]

I haven't had this happen for such a long time I forget what the cause is. I would start by attaching a hose and gun in the equipment room to eliminate the possibility of a bad check valve or solenoid. I'm leaning toward a regulator issue, but can't put my finger on it.
I'll try and jog my memory with a stiff drink , but I'm sure MEP will be along shortly to give you the correct answer.

BTW: If you do not already have a copy of Paul Noone's Cat pump repair guide that appeared in SSCWN about 8 years ago you should really get one! Heck, I need to order one. I think my wife threw it out but she denies it, this is the only place I can say that and not catch her wrath.

 

[MEP001]

Start by changing the tip.

You could have a check valve not seating, either the weep at the pump or possibly the spot-free at the bay. If it was your tire cleaner/presoak check valve you'd likely have blown tubing or water spewing from your air regulators by now.

If the pump was run for long with the bay lines frozen, the high-pressure seals could be damaged. If the pump sounds ok and isn't pulsating or clattering it's not the inlet check valve on the hot water feed. Bad high-pressure seals won't cause the pump to leak.

 

[Buzzie8]

Last time this happen to me I had a hose leaking in the trough. It took a while to seep through the ceiling.

 

[Bubbles Galore]

Thanks for the tips guys. I will have to check it out tomorrow. I hope it's not a blown hose...I can't wait for winter to be over...

 

[Tpoppa]

I had a back check valve on a weep line that was causing some odd pressure readings. Every time one a certain bay would run it would push a small volume of water though the weep manifold to the other bays.

Also, on a pump that was losing pressure I've seen the psi numbers jump when the trigger on the gun was released.

 

[mjwalsh]

Bubbles,

My guess would be the spot free check valve.

MJ

 

[Bubbles Galore]

Looks like to the roof I go tonight.

 

[Waxman]

I haven't had this happen for such a long time I forget what the cause is. I would start by attaching a hose and gun in the equipment room to eliminate the possibility of a bad check valve or solenoid. I'm leaning toward a regulator issue, but can't put my finger on it.
I'll try and jog my memory with a stiff drink , but I'm sure MEP will be along shortly to give you the correct answer.

BTW: If you do not already have a copy of Paul Noone's Cat pump repair guide that appeared in SSCWN about 8 years ago you should really get one! Heck, I need to order one. I think my wife threw it out but she denies it, this is the only place I can say that and not catch her wrath.

Order 2 Eric; 1 for the Waxman.

 

[MEP001]

Looks like to the roof I go tonight.

You can see if it's the spot-free check valve without getting on the roof - disconnect the tubing at the solenoid for that bay and turn on the high pressure.

 

[Bob-O]

Had this happen once before, it was a bad pressure regulator on the pump.

 

[I.B. Washincars]

I had the exact same problem with a bay today. It was the last bay and as I walked past the others I noticed they had water coming out of the wands. I was a bad check valve for the weep on the last bay. With a new check valve all was well 15 minutes later.

 

[MEP001]

15 minutes for a check valve change? Must be some kind of nightmarish plumbing to the weep system.

 

[I.B. Washincars]

Must be some kind of nightmarish plumbing to the weep system.

It's not the greatest by a long shot, but I wasn't running a race either.

 

[Greg]

I open the bay back up and as soon as a customer kicks on one of the high pressure options, I know something is up (just by hearing it). I look at the pressure gauge and its only reading 900 psi while prior to the freeze up it was running steady at 1200. I change out the gauge and get the same results. Weird thing is that when the customer lets off the trigger, the pressure jumps up to around 1200 psi. I try to adjust the pressure regulator and nothing.

Hi Bubbles,
What you could "hearing" is the pump starving for water.
Your pump may be starving for water when in spray mode.
When the trigger is pulled, the water draw through the inlet line to the pump is greater than when the trigger is released.
When the trigger is released, water bypasses from the regulator to the pump inlet and reduces draw of water through the inlet line.

I don't know your pump inlet conditions, however I did assist a distributor to a similar issue and it was traced to a bad zero pressure regulator and a colapsing hose located on the pump supply line. Pressure was dropping to 800 psi when trigger was pulled and would jump back up to 1150 when trigger was released.
In this case, after changing the ZPR and removing the hose between the ZPR and pump inlet everything returned to normal.

Hope this helps - Good luck.

Greg Thoennes
Sales & Technical Support
Arimitsu Pumps

 

[Bubbles Galore]

Well I checked the check valves and everything appeared to work as it was supposed to. I will have to do a little bit better looking for my pressure regulators and switch that out next...thank god for 5 other bays...

 

[MEP001]

The regulator is in my experience the least likely thing to cause the problem you describe.

 

[Greg]

I will have to do a little bit better looking for my pressure regulators and switch that out next.

Hi Bubbles,
If your pump stands are equiped with Zero Pressure Regulators, they will look like this and are installed on the pump supply side;
http://www.kleen-ritecorp.com/p-17263-zero-pressure-regulator-weep.aspx
I agree with MEP, your "regulator" which is on the pump discharge side is not a likely cause to your symptoms.

Greg Thoennes
Sales & Tech. Suupport
Arimitsu Pumps

 

[JIMT]

Greg,
I have never seen a zero pressure regulator used. How many gallons per minute will they flow? Is there a different feel in the bay as the trigger is pulled and released?
Thanks,
JIMT

 

[MEP001]

I don't recall the exact flow rating, but it's at least 5 GPM. Despite its claim, there is a brief recovery time for a change in flow. I had to use them in one remodel and was able to solve that problem by looping the regulator's bypass back in to the inlet of the zero-pressure regulator so the flow through it was always the same.