Multi stage booster pump fried.....

[Greg Pack]

One of those days I guess....

About six weeks ago, I has a dayton PC32 1.5 HP multi stage booster pump mounted on a Pur Clean RO system kick the bucket. The pumps was over five years old at a fairly busy car wash so I didn't think too much of it. I replaced it. The replacement lasted about three weeks. I came in one morning and smelled the tell-tale smell of a fried motor. The megohmeter showed the motor had shorted out. I checked all voltages, contactor resistance, etc. Everything looked OK. I attributed the replacement motor going bad to a defective unit from the factory. I got a replacement under warranty from Grainger and installed it. Running amps were within specs and everything looked and sounded fine. Well, today, about three weeks after the second replacement was installed, I walk in the equipment room and smell the pump again. The motor housing was very hot to the touch. I had enough, so I just cut if off and headed home.

At this point I'm assuming that something other than a bad motor is up. This pump is mounted on a Pur Clean floor mount two membrane unit. The pump is mounted vertically, nose down, which is supposed to be an acceptable mounting position. There is no overload protection on the pump, just a two pole contactor. I guess I'm going to have look closer at the breaker sizing when I get there tomorrow. I thought about taking the pump off and carrying to my local motor shop to have them help with a post mortem, but I thought I'd ask around here for personal experience or perhaps something I have overlooked. I've never had bad luck with these Dayton pumps before, but did talk to one OEM guy who said that "they don't make them (pumps) like they used to" and he has had several bad pumps right out of the box. At this point I feel it's unlikely to get two dogs in a row, and would be hesitant to ask Grainger to eat this one. But I really don't want to buy another Dayton pump until I know what the deal is. Anyway, just looking for some answers. Any input is appreciated. Thanks....

 

[Washmee]

I assume this pump is a single phase 230V motor? The ones I have contain a thermal overload that shuts the motor down if it gets too hot. I would check the contact points on the contactor to make sure you are getting full power. They could be burned and prevent one of the legs from getting full amperage under a load.

 

[Randy]

We don’t buy anything from Grainger anymore. For the most part their stuff anymore is just junk. We’ve used to buy a lot from them years ago but they stuff has gotten to be worse all the time, bad motors out of the box, motors that go bad with a year etc. My motor shop guy won’t work on a Dayton motor anymore, he said they are basically a throw away motor.

 

[Bubbles Galore]

Hmmm....I just bought a dayton 1.5 hp for my spot free upgrades...uh oh.

 

[MEP001]

I wouldn't hesitate to take it back for a second warranty since it sounds like you've done nothing wrong to harm the pump. You mounted it in an "acceptable configuration" and confirmed that it's not running too much load. The only concern I'd have is having to replace it over and over every three weeks.

Hmmm....I just bought a dayton 1.5 hp for my spot free upgrades...uh oh.

They used to be good units. The one I linked to you is the same one I put on the Vector 7 years ago as the spot-free booster pump. If you're worried you could always return it.

 

[Bubbles Galore]

They used to be good units. The one I linked to you is the same one I put on the Vector 7 years ago as the spot-free booster pump. If you're worried you could always return it.

I have a 2 hp dayton booster that runs my self serve bays and that runs like a champ...no returns for me, I will wait and see how it works out, if I have the same problems, Grainger is only a phone call away.

 

[Greg Pack]

Went back last night to straight plumb the membranes off city pressure. I am producing a gallon per minute RO and have a huge storage tank installed by the previous owner, that should buy me some time, until the weekend anyway. It is indeed a 230V single phase motor and I confirmed proper wiring configuration for 230V operation. I could reach inside the housing inlet and spin the shaft with my finger. wires on contactor are tight. There is now some charring on one leg of the contactor that wasn't there before, but the contacts look OK. The specs on this motor say it is thermally protected, but when I found it that baby was hot enough to fry an egg. I put a multimeter on one leg and it was pulling 40 amps. Strange thing is that (if the breaker labels are right)it's on a 20 amp circuit. I did not have a multimeter to test a capacitor that size with me. The OEM guy I talked to told me told Flint & walling builds the pumps for Grainger. The motor shop I occasionally use is a F&W service center so I'm gonna see if I can carry it there for an evaluation. Regardless of what Grainger tells me to do I will probably carry it by anyway to get their take.

I will let you guys know what I find out, if anything. I will also call Grainger and Pur Clean and see what they say about the situation. If I can' get a reasonable answer from anyone on what happened I will replace the breaker and contactor just to be safe, and if new motor number three goes out I will definitely try another brand.

 

[Greg Pack]

Long day yesterday.......

As soon at they were open I called Pur Clean tech support to see if there was anything on the unit outside of the pump that could cause motor failure. The tech came up with a scenario of the unit being starved for water by the carbon filter, in conjunction with a failed pressure switch. He stated that pump needs an inlet flow of 20 GPM. That conflicts with F&W data for the pump, but I asume this guy is talking from experience. I told him I didn't think we had a water starvation problem, but would check. I did flow an adequate amount and checked the pressure switch for proper operation.

I called Grainger tech support, (which was surprisingly good) who couldn't figure out what was wrong , so they connected me to F&W tech support. This guy also could't figure out what was wrong, so he authorized me to carry it to the local F&W service center.

I took the unit to be diagnosed. The tech guy quickly determined that it had a bad capacitor. He is a crusty old guy who has worked on electric motors since they were steam powered. He said that he has seen more bad capacitors in the past three years than he has seen prior to that. He grumbled something about cheap Chinese capacitors and then proceeded to install a cheap Chinese capacitor in my pump. I made a note to buy another meter that measure capacitance.

Just to be safe I dropped by the electric supply house and picked up a new breaker. My 20 amp breaker was trying to pull 40 amps and did not trip. I tightened all the wires in the circuit I could find. I reinstalled the pump and another used (but visually OK) contactor I had and fired it up. The pump fired up and started making RO. I checked all measurements and the were what I would consider "normal", so the tank started filling back up.

Thirty minutes in I started to smell a strong, offensive smell. Not an electrical burning smell, but a cross between ammonia and road-kill. The pump was still running. I rechecked electrical values and we were still pulling the same amperage as before and voltage was OK. Even though the wash wasn't busy and the tank wasn't full curiosity got the best of me and I turned the unit off, then back on. The motor just hummed.

I removed the pump and took it back to the motor shop. It had blown the capacitor again. The guy took a harder look at the unit, megged the windings, etc and they megged out OK. He basically was at a loss as to what happened, but questioned the quality of my power and if I was suffering any voltage losses. His only theory was that perhaps that since I'm on a 208 Volt system and running about 212 volts between legs that the unit may be trying to continually energize the start circuit. He encouraged me to run a 120 volt circuit to the pump if possible. The rest of the RO is set up at 230 with no neutral so that would be a huge PITA. Again I was sent on my way with a running pump. I reinstalled it, I also swapped to another adjacent circuit. The RO unit was also wired with twist lock plugs, I removed the twist lock plug and straight wired it in with wire nuts. The unit is working as of last night.

So bottom, line, I still don't know what the issue is. It basically burned up my entire day yesterday . I will buy another capacitor to keep over the weekend. If it fails again, I will wire up a 120V circuit to run the pump and see if that helps.

 

[Greg Pack]

BTW, during this evaluation of the Pur Clean unit I discovered something that may be of note to purclean system owners. The pressure switch is located "upstream" of the asco water inlet solenoid. If there is adequate inlet pressure but the solenoid fails to open the pump will still operate and starve for water. I plan to modify this.

 

[MEP001]

The 208 voltage instead of 230 shouldn't matter, except that it's going to pull more amps. The inlet flow rating would make sense that it's causing excessive stain on the motor if you were trying to pump that volume out the other side, but I doubt you're exceeding 5 GPM total.

Since you'll have to rewire everything to switch it to 120v, have you thought about changing over to 3-phase instead?

 

[Greg Pack]

Well, I did talk to the F&W support guy again yesterday. He said 207 volts across the legs was the acceptable low limit. If voltage dropped below that he could see an attempt made by the motor to engage the starter winding, overheating and popping the capacitor. I never saw anything below 212V with other equipment on. I have an old Fluke 87 that will measure voltage range and give me historic high/low readings . I may install that today and get some reading with everything running.

Three phase would ultimately be the best, but I know myself too well. In other words, I am lazy and take the path of least resistance. If I can get this pump running reliably I will forget about it......

I put the unit on another circuit and bypassed the quick disconnect plug. it ran all day yesterday. We will see if it makes it past the magic three week mark. Spare capacitors were only $5, so I bought two.

 

[Greg Pack]

Just an update- Pump seems to be working fine with no further problems. I am suspicious of the quick disconnect plug. Even though it looks fine it's about the only item left.

Looking around a bit, I can't find many single phase pumps designed to work at lower voltage (208 Volts) until you get to 2 HP, below that, it seems most are rated for 240. I've never had a problem using 240 motor on a 208 service until now, perhaps just a marginal connection was enough to stress the motor too much.

I also bought a new multimeter that measures capacitance. I've never bothered checking capacitors on inexpensive motors, but will make this part of my checks now. The meter I bought was a Klein cl2000. This meter will do pretty much everything. It measures both AC & DC voltage AND current, capacitance, frequency(useful when working on generators). It even has a little voltage detector built into the tip. It does not sample as often as my fluke meter, but so far it seems like a great all in one tool.

If it blows again I will try installing a buck-boost transformer. Thanks for the input guys.

 

[JIMT]

The capacitor is only used to start the motor. Did the service man check the centrifugal switch in the motor? There are two sets of contacts, one for capacitor start and then run. Both must be good or the motor will fail. If the motor starts alright and then gets hot while running it is not the capacitor. If you are running too high outlet pressure this will put too much load on the motor.
I had a problem with a pump and I put a pressure gage on the inlet of the pump and when the pump started the pressure went zero. I had too boost the water pressure to the pump to solve the problem.

 

[Washmee]

Just got done reinstalling my Dayton 1.5hp booster pump for my spot free. It was installed new less than a year ago and last Monday it started kicking the breaker. Took it to my motor guy and he took one look at it and said it was one of the new Dayton motors that are now manufactured in China. After he disassembled it he found that the leads to the windings were not properly secured and one of them had slowly rubbed against the casing causing a dead short. It was obvious to him that the person who assembled the motor just took a shortcut and left out the ties that secure the leads. And this was not the first one he had serviced with the same problem. It only cost me $75 for the repair, but I will have second thoughts about buying another Dayton motor.

 

[mac]

Thyis discussion shows me two distinct things. One, we are getting all kinds of crap from China. Two, do not use a single phase motor for any application when you have three phase at the site. An overload on the motor starter wouldn't hurt either.

 

[Randy]

Over the last few years we’ve had nothing but problems with products from Grainger/Dayton that we do buy from them anymore. Years ago they were OK now there are nothing but junk. My motor guy says the motors are like a Bic lighter when they don’t work anymore toss it and buy a new one. On the other hand motors from the other manufactures aren’t much better.

 

[Washmee]

Just got back from my local Grainger branch office. Even though I bought the unit from a reseller on the internet(www.drillspot.com) they are stepping up to the plate and offering me a huge discount on a complete new pump(More than 50% off). They also advised me that all of the multi stage booster pumps offered by them are now powered by motors made by AO Smith.