HELP!... big pressure drop during IBA HP functions

[GregF]

Every time our Laser 4000 is running the HP rinse cycle, we have a MAJOR pressure loss in several of our self-serve bays. Bays 1 & 2 aren't affected nearly as much as bays 3 & 4, and bay 5 isn't quite as bad either. Had a backflow guy in who took the backflow apart and got some debris out. Hoped that solved the problem, but no... Installed a new 2" PRV valve (on a 2" line), but no, didn't help. Had an expert water softener guy come in and within minutes diagnosed a bad piston in one of the two softener heads. Replaced the piston, but that didn't solve the problem either. (City) water pressure coming into the backflow is about 75 psi. We have four places on the backflow where we can check pressure, and between the 2nd and 3rd places, which are virtually right beside each other, the pressure drops from 75 to about 68 psi. Still about 68 before the PRV valve and (I believe) after the water softeners. Manipulating the pressure regulators on SS pumps 3 & 4 does virtually nothing.

Wash is approx. 11 years old. Have never had this kind of problem in the past. City says the supply is fine, that it's a volume problem on our side. Says that our pipes are "undersized" now (i.e., clogged arteries) and basically need to replace our plumbing. Backflow guy thinks it the water softeners or PRV. He suggested bypassing the PRV to see if that solves it. Water softener guy says it's not the softeners, that we might be losing a couple of psi there, but that's it. He says we ought to install a 3" PRV on our 2" line, even though our 2" PRV is virtually "wide open." Could also set both softeners to recharge at night to make sure they're wide open during the day (...I don't know why it's not already set this way or why he didn't do that while he was there, for the 2nd time from 60 miles away, with my ops mgr). Now what??? Each time I have an expert in it's costing me about 3 or 4 hundred $$. Hasn't gotten better at all. Just a lot of head-scratching going on. Should have come here to where the real experts are in the 1st place. Please help!!!

 

[I.B. Washincars]

Have you tried running with the softener bypassed? All of mine have a ball valve in the manifold that can be opened to bypass it. If your pumps pick back up, you'll instantly know that the softener is the issue.

 

[GregF]

Yes, we tried bypassing the softeners, too, and there was still a huge drop in pressure, just not quite as "huge" as when they weren't bypassed. Bays 3 & 4 (and 1 today, too) drop from 1250 psi to 500 psi on their pump outlet gauges, while bays 2 and 5 only experience a slight (but noticeable) decrease.

 

[lag]

First of all it may well be a volume issue. You may want to remove a couple of feed lines, to your pumps and install a t with a gauge and see if you do have 68 psi on or at your pumps, then if you do fire everything up,and see if the pressure does drop. If anything you should be able to see if you do maintain pressure ,and at what psi.

on the self serve side do you use a holding tank for hot water to your bays for use with soap ? if you do fire everything up and turn to soap,and see if the pump pressure drops then. that may also help determine if it is a cold water issue also.

next do you use hot and cold to your laser? or 2 colds? or one cold? you may want to try and throttle down your ball valves a little, fire up the HP pump,and close the ball valves a little bit to a point where the water in the tank just keeps up. this may help a little.

for the layout you describe 68 psi should be ok. We run at one of our locations at 75 psi,and we have 4 lasers and 3 self serves, We do however have a repress. pump on the incoming city line to maintain pressure.

I wouldn't think it would be a plumbing issue, with your pipes after all this time. Unless you have really lousy water. Sounds more like all trades are passing the buck. Install some pressure gauges ,and see for yourself ,whats going on.

Sorry for the ramble,in my reply. Good luck keep us posted

 

[GregF]

We have a hot and cold running to the Laser and, now that I think about it, the cold water volume at the pump station was also one of the headaches we were experiencing. We kept getting low water alerts because the tank wasn't filling fast enough (with the ball valve wide open).

We do have a hot water storage tank supplying the SS soap. I'll ask the site mgr if he's noticed the pressure dropping when that's in use, too.

I'll install gauges on the feed lines and see what we're getting.

Thanks.

 

[MEP001]

You may have a problem with the self-serve bays sucking air through the open valve in the Laser tank. I've seen this happen before, but it's still caused by inadequate flow. Put a gauge somewhere after the softeners to check pressures when the softener is in service, regenerating and completely bypassed, and check the pressure during a wash.

 

[galen]

You might have a flow meter on your water softener. Depending on what make you have. You could check that also. I push a button on mine and it shows a real time flow rate. Good for diagnostics.

 

[GregF]

We've installed gauges after the PRV (before the softeners) and on both the hot and cold feed lines to the SS pump station. While the SS bays are in use, but the automatic isn't, we're getting 64 psi after the PRV, 60 on the cold feed line, and 61 on the hot.

When the automatic IS in use, the gauge after the PRV drops to 42 and both the hot and cold feed lines drop to approx. 20 psi.

Now we're going to bypass the softeners and see what happens.

 

[GregF]

While bypassing the softeners now, with the automatic and at least one SS bay in use, we're getting 58 psi right after the backflow, 40 psi right after the PRV (with it wide open), and 38 psi on both the hot and cold feed lines.

While nothing is running, we're getting about 64 psi right after the backflow (which the water dept says is a meaningless measure).

While the automatic is in use and the SS's aren't, we're getting 42 psi after the PRV.

 

[MEP001]

While nothing is running, we're getting about 64 psi right after the backflow (which the water dept says is a meaningless measure).

They're right - restriction is clearly your concern, not static pressure.

By your tests you have pinpointed the softener as the culprit.

 

[GregF]

Our 2nd softener expert concurs with you. He said the beads are starting to bind together and are two different colors. I just wish the 1st softener guy would have checked it out (like I requested) the 2nd time we brought him in, instead of insisting that, in spite of being 11 years old, the resin beads were just fine and that it had to be something else (oh, and then billing me for 5 hours of labor for his two hrs of drive time and 3 hrs of explaining to my site mgr how water softeners work).

 

[GregF]

Also, I'd like to thank all of you for your help and your suggestions. I really appreciate it!

 

[GregF]

Update - We had the water softeners re-bed and took out our PRV valve and that seemed to solve our problems until this last weekend. Now we're back to having problems with bays 3 and 4. Bays 1 and 5 aren't affected at all, and bay 2 has just a slight pressure loss. When the HP pump on the automatic is NOT running, we have 65 psi where the PRV "was" and 64 psi on both the hot and cold feed lines at the SS pump station. When the hp pump on the automatic IS running, we have 50 psi where the PRV was and 20 psi at the SS pump station. We're in the process of replacing the feed line hoses to the pump station. If that doesn't solve the problem, can anyone tell me what the likely culprit is, or what to check next? Thanks!

 

[GregF]

Still the softeners?

Replaced the feed line hoses and that didn't help. Bypassed the softeners again and now pressure is consistent throughout the system. Calling the softener guys to come back out again. What the heck could be wrong with these softeners??

 

[GregF]

Softeners

Our latest recommendation from the softener guys is to buy new timers and schedule the softeners to cycle from midnight to 4 a.m. only. Also, it was suggested that we install a hub and lateral (i.e., crow's foot) system within the softeners to increase "capacity."

If the timers are set to cycle only at night instead of on a "per gallons softened" basis, would we gradually "lose" soft water throughout the day on really busy days?

Why have the softeners performed fine for the better part of ten years, but now, all of a sudden, they can't keep up and need to be scheduled to cycle only at night?

Is there a point in time where it just makes sense to buy new softeners?

 

[MEP001]

It doesn't make sense that 20 PSI at the pumps isn't enough. It would help to know more about your setup. I would think that as long as there's pressure to it, there shouldn't be an issue with pump supply unless they're drawing air. I would focus on that possibility rather than letting someone try and sell you a softener that you probably don't need.

 

[dustpan]

Good point. The pumps don?t need a pressurized water supply. The pumps create suction on the inlet, and if there is a leak in the supply it can draw air through the leak. When the automatic comes on, the pressure feeding the self-serve pumps drops, the suction on their intakes increase. When the pumps suck air they drop pressure and rattle like ****. Check for water leaking from the supply feeding bays one and two. The floor is probably wet under it.