high pressure problems

[metzger1]

I could really use some help here. We have a Lappierre turbo with 2 membranes which was working just fine until a couple days ago when we could only get the high pressure to about 100psi. Called Lappierre and they figured a blockage in the pressure cylinder so he walked us through taking it apart and checking all the stages for problems. There was a few little pieces of crap, but not enough to be a problem, so we cleaned it all up and put it back together and still had the same problem. In trying to diagnose the problem we turned the pressure pump on and off several time, and after a few times, it suddenly jumped a bit in pressure, and after another few times of turning it on and off, it finally got up to 300psi and ran fine for the next few hours till we ran out of sap. The guy at Lappierre figured it was some obstruction that finally got worked out, which made sense until it did the same thing the next day when we went to use it again. Again, we had to turn it on and off multiple times to finally get the pressure up, after which it ran fine for hours, and today was the same thing. The guy at Lappierre still thinks it's an obstruction problem and is trying to get another high pressure cylinder, pump, or motor for us from one of their dealers as we are in central NY. Problem is, we don't really know where the actual problem is and I am hoping that someone out there has had this same problem and knows a solution.

Any help, suggestions or advice would be greatly appreciated.

[Machinist67]

Check your amps when the pressure is low and the check it when it is high and see if you get different readings. Also check for a voltage drop. You could have a loose wire in you electrical conections and you may not be getting full voltage to the motor. Another thing would be to check the RPM's

[Maplewalnut]

Do you have a strainer plumbed in line before your feed pump?

[metzger1]

I think that it does seem to be something to do with electrical. When the problem with the pressure first started, we also had problems with the breaker for the RO overheating and tripping. It had a 40 amp and apparently should have been a 50 amp, but it hadn't given us a problem before. I switched it out for a 50 and haven't had any problems with that since, but it seems a very strange coincidence if the two problems aren't related. I know basic electrical, but I don't know how to test for amps. I will see if I can get someone to check that. Any idea where wires might be loose? I did take off the cover for the wiring box on the motor but everything in there looked fine. We do have a sap filter before the feed pump, and our low pressure is staying where it should, so the guy from Lappierre says it can't be a problem in the feed pump.

[PATheron]

Metz- Doesn't sound like this is your prob but my machine will airlock bad sometimes starting it. Thing is the low pressure wont come up which your saying yours does. Starting and stopping it will help get the air out. Theres a red bleader button on the sap filter that helps bleed it. Ive never had the low pressure good though and not have the high pressure pump not work other than if the bearing goes bad in it but it makes tons of noise if that happens. You can go to radio shack and get a cheap clamp on ac ampmeter and see how many amps the motor draws. Theron

[Machinist67]

I think that it does seem to be something to do with electrical. When the problem with the pressure first started, we also had problems with the breaker for the RO overheating and tripping. It had a 40 amp and apparently should have been a 50 amp, but it hadn't given us a problem before. I switched it out for a 50 and haven't had any problems with that since, but it seems a very strange coincidence if the two problems aren't related. I know basic electrical, but I don't know how to test for amps. I will see if I can get someone to check that. Any idea where wires might be loose? I did take off the cover for the wiring box on the motor but everything in there looked fine. We do have a sap filter before the feed pump, and our low pressure is staying where it should, so the guy from Lappierre says it can't be a problem in the feed pump. Shut it down and start checking all connections starting at the breaker. (single phase or 3 phase?) Evern check the grounds and the common. You may have a loose screw. If you can try and use a better connector than wire nuts ie (staycon crimps). I have seen wire nuts vibrate loose. are you noticing anything else in the sugar shack being effected by the electrical draw?

[Maplewalnut]

Agree with Theron. I know I had not cleaned my stainer in a while and had the same problem. I was not getting sufficient flow to keep pump from shutting off. Bleed the system to make sure all air is out. The other thing to check is your pre-filter. It may need to be changed if it is gummed up.

[metzger1]

All the connections on the machine itself seem to be tight. They used heat shrink stuff around most of them and I can't imagine they are loose under that, do you think? I didn't check the screws on the breakers inside the machine. I will do that. Also I just thought about the outlet that the machine plugs into. Something could be loose in there I guess. I will check that as well. The connections on the breaker in the main building panel seem tight. We change the sap filter regularly, and the low pressure gauge is showing plenty of flow through that. Thanks for the help guys, any other ideas will continue to be appreciated.

[metzger1]

Also, it is single phase. And it is not shutting itself off at all, it just doesn't want to bring up the pressure without us doing multiple on and off cycles.

[maplwrks]

Have you opened up the panel on the RO to see if you have good connections at the breaker? It's acting like you may be down a leg of power maybe? Make sure all of your breakers and resets are ready to go.....grasping at straws...

[metzger1]

And nothing else in the sugar house seems to be affected. The vac is working fine, which is the only other thing that has a big draw, and even when I turn that off, I still have the same problems with the RO, so it seems like it must be only the wiring to or in the RO.

[metzger1]

I did just check the breakers in the machine, and all the screws on the breakers are tight, and the breakers weren't tripped, but the screws inside the outlet were not super tight, and the plug was out just a little. Doesn't seem like enough, but will see what happens this afternoon when we start to try and concentrate again.

[metzger1]

would it still be working at all if a reset was tripped?

[maplwrks]

Depends on which reset was tripped

[metzger1]

all the resets are fine, and still had the same problem when we went to concentrate today. Running out of ideas......

[Machinist67]

Where are all your pressure gauges? Do you have a gauge on the incoming sap line before the pump? If so what is the reading? Also can you get the model of this pump?(looking at NPSHR)
Is your sap tank always full before you start up? Any chance you could be getting air into the suction line?

[Brent]

Watch the level in your feed tank. If you get lots of pressure when the level in the feed tank is high and then the pressure drop coincides with a low level in the feed tank it may be suction problems. The pumps are good at pushing (pressure) but not so good at sucking. We had to put our feed tank up on a half dozen skids to get it high enough to keep a good flow into the feed pump.

[ennismaple]

Watch the level in your feed tank. If you get lots of pressure when the level in the feed tank is high and then the pressure drop coincides with a low level in the feed tank it may be suction problems. The pumps are good at pushing (pressure) but not so good at sucking. We had to put our feed tank up on a half dozen skids to get it high enough to keep a good flow into the feed pump.

We don't have that problem with our CDL RO. The Lapierre may be different, but the bottom of our 3,000 gallon feed tank is maybe 1" higher than the RO feed pump and we haven't had problems with supply pressure.

[metzger1]

Thanks for all the help guys. It turned out to be a combination of things. Eric from Lappierre gave us advice over the phone, and with his help we discovered that there was some damaged stages in the high pressure pump, and so he came out to bring us parts and fix it, and while there he also discovered that we had low power in the building. We got the power company out there the next day and they put in a new transformer and got our power back up to full volts. We still have some issues, but Eric is working on getting those resolved and we are at least able to concentrate again. Thanks again guys.