Jabsco Sensor Max 14 cutting out

First problem of the 2022 season! We splashed this morning and ran the hour back to the marina. First order of business was to fill the fresh water tank and flush the lines.

I was impressed at the pressure and flow rate at each sink as it was significantly higher than last year. The boat was inside heated storage all winter and nothing froze. The fresh water tank and hot water heater were drained during storage.

After a couple minutes the wife said “Hey, the water is off.” Sure enough, the breaker had popped. I turned it back on and the pump ran fine until the breaker popped a couple minutes later. The connections at the breaker are clean and tight. The Jabsco Sensor Max 14 motor was cool to the touch. The wiring at the pump and as far as I could trace was sweaty from being cold, but clean and intact.

I read in the manual that the motor will protect itself by shutting off when the voltage gets over 14.5 volts. The house bank charge state was at 74% at the end of the winter, so the charger was charging at 14.7 volts. Would that pop the breaker in my DC panel?

Short Answer is No, the voltage would NOT pop the breaker. The pump would internally not run, but the breaker would remain on.

The breaker is popping because of over amperage and doing what it is designed to do.

Now, the tricky part. Breakers were never designed to be used as on/off switches so that wear and tear does take a toll.

You need to measure the amperage with a volt meter and clamp to see if the motor is causing an issue.

After some further investigation I now have the pump running constantly until it presumably pops the breaker. It’s easy to hear in the salon and I definitely heard the pump come on initially and cycle off when it made pressure, so this constant run thing is new.

Of course this is an obsolete model and my paper manual is two hours away. Looks like I will be looking for a new sensor.

AdmiralS said:

You need to measure the amperage with a volt meter and clamp to see if the motor is causing an issue.

Click to expand...

Thanks Admiral. For better or worse, the only meter I have today measured only AC amps. DC amps will have to wait for next week.

No Problem. I cant speak highly enough of the newer Marco Gear type pumps that Helmsman is using. They are great pumps. Variable Speed and quiet. Pricey, but well worth it in my opinion.

The model they are using is the Marco UP 6

https://www.fisheriessupply.com/marco-up6-e-water-pressure-pump/m164-622-15

The Jabsco Sensor Max pumps have a very bad reputation for reliability in the control circuitry. I've replaced a couple myself. Most recently with the Marco gear pumps, also variable speed and constant pressure. These have been more reliable for me, have yet to replace one. They are however not self priming like the Jabsco, so if the pump is above the water tank you will have to prime it (simple procedure) and if there are any vacuum leaks in the inlet side, or if you run it out of water, you have to prime it again. If the pump is below the tank, it will self prime.

This is the start (well, a false start really) of our third season with this pump and it always had rather anemic flow. Today’s start up produced the same kind of flow I get at our dirt home; way more than in the past. Then it started running non-stop even against closed faucets. Makes more noise too. Are those symptoms consistent with a dying Sensor-Max pump?

HeadedToTexas said:

This is the start (well, a false start really) of our third season with this pump and it always had rather anemic flow. Today’s start up produced the same kind of flow I get at our dirt home; way more than in the past. Then it started running non-stop even against closed faucets. Makes more noise too. Are those symptoms consistent with a dying Sensor-Max pump?

Click to expand...

those are definitely symptoms of a failing pump. when it was delivering more water, it was probably because the pressure switch was failing and allowing the pump to over pressure. that is what made the breaker blow. now it's been running too high a pressure and something in the pump is filing. i think those are diaphragm pumps, and it's probably got a bad diaphragm or check valve. it might be possible to disassemble and repair, but hard to say.

Bmarler said:

those are definitely symptoms of a failing pump. when it was delivering more water, it was probably because the pressure switch was failing and allowing the pump to over pressure. that is what made the breaker blow. now it's been running too high a pressure and something in the pump is filing. i think those are diaphragm pumps, and it's probably got a bad diaphragm or check valve. it might be possible to disassemble and repair, but hard to say.

Click to expand...

Thanks B, that makes a lot of sense. I believe rebuild kits for the Sensor-Max 14 are still available. Question is, am I chasing good money with bad parts (or however that saying goes)? Is it time to upgrade to what Helmsman starting using sometime after buying Mariner?

AdmiralS said:

No Problem. I cant speak highly enough of the newer Marco Gear type pumps that Helmsman is using. They are great pumps. Variable Speed and quiet. Pricey, but well worth it in my opinion.

The model they are using is the Marco UP 6

https://www.fisheriessupply.com/marco-up6-e-water-pressure-pump/m164-622-15

Click to expand...

Cool pump. I can see why it is a better and more efficient design. Marco also makes a 3 gpm model that is more in line with my boat's flow needs. See any problem using the UP 3 version?

https://www.fisheriessupply.com/marco-up3-e-water-pressure-pump/m164-602-15

HeadedToTexas said:

Thanks B, that makes a lot of sense. I believe rebuild kits for the Sensor-Max 14 are still available. Question is, am I chasing good money with bad parts (or however that saying goes)? Is it time to upgrade to what Helmsman starting using sometime after buying Mariner?



Cool pump. I can see why it is a better and more efficient design. Marco also makes a 3 gpm model that is more in line with my boat's flow needs. See any problem using the UP 3 version?

https://www.fisheriessupply.com/marco-up3-e-water-pressure-pump/m164-602-15

Click to expand...

i would always opt for the larger pump if it can fit in the installation parameters. plumbing size, amp draw, etc...
you say the sensor-max was always a bit anemic, why not upgrade to a much larger pump? if i was in the market for a new pump i'd seriously be looking at the larger marco unit. you only open the tap as far as you need, right? plus,it's nice to have extra capacity when someone opens a tap down below when you're doing something up top.
as long as the wiring circuit handles the load, it would be a no-brainer for me.
i guess you have to think about tank capacity too. if you have someone onboard that leaves a tap open full blast while brushing teeth, a smaller pump might be best...

The manual lists the following troubleshooting items for our Sensor-Max 14 pump:

1. Empty water tank
2. Punctured pump diaphragm
3. Discharge line leak
4. Defective pressure switch
5. Insufficient voltage
6. Debris under flapper valves

Many of those are easily eliminated. The tank had plenty of water, the voltage is okay, there were no leaks, the pump produced excellent flow (and therefore I believe it has no punctured diaphragms). That leaves a defective pressure switch and debris under the flappers. Since the pump delivers plenty of flow, it should still shut off when the faucets are all closed even with debris, and that debris may work its way out. I think the defective pressure switch is the likely culprit. Make sense?

While buying a new Marco MAT M164-602-15 UP3 makes a lot of sense whether or not I can revive the old Jabsco, I think the sensor warrants a thorough inspection and cleaning. I have plenty of experience with other pressure gauges and sensors and it is no uncommon for them to exhibit off behaviors when particulate accumulates in their inlets. Does that make sense too?

HeadedToTexas said:

Cool pump. I can see why it is a better and more efficient design. Marco also makes a 3 gpm model that is more in line with my boat's flow needs. See any problem using the UP 3 version?

https://www.fisheriessupply.com/marco-up3-e-water-pressure-pump/m164-602-15

Click to expand...

I'm using the 3 gpm in both my trawler and my RV. More pressure and flow than the Whale and Jabsco they replaced, plenty unless you have two showers in simultaneous use.

Our water flow from the tank has always been very low, but not low enough to rise high enough on the priority list to investigate. The flow was prodigious this spring when I opened a few faucets to blow the air out. I doubt it was 3 gpm, but it was plenty. Until this spring, it was maybe a quarter to a third of what it was. My read on the improvement is that the right pump (like a Marco UP3) will deliver plenty of water.

Check accumulator tank. Mine just failed and took out pump. PRS switch also failed and may have started whole process.

It was 30 years old Groco and built of solid brass. Motor still works.

My system does not have an accumulator tank, but I bet it was the pressure switch. I hope to find some debris in the switch mechanism that is keeping it from regulating the pump because if I don't, I will be without water until a Marco UP3 arrives some time later this month.

I don't like the pressure switches in the Jabsco pumps. I dumped them years ago.
THey are BARELY able to manage the current load. DC controlling a motor will create a LARGE spark when disconnected to shut down the motor. That spark burns the contacts each and every time it operates. After a while, sure it can be several years, the switch will fail.

A spare should be carried.

Even better would be to use a RELAY to do the actual control of the motor with the pressure switch controlling the relay OR Use a REAL pump switch which has far heavier duty contacts and 4 of them so the contact burning is of far less a problem.

I also use a reverse polarity diode to further quash the sparking.

My last pump switch lasted 20 years. It was not the contacts that finally caused a failure.

Even the last Jabsco pump I installed a month ago uses that same pump switch with a bit of monkey mousing so it too will carry on for many years.


Anemic flow? I am going to add , how did you test the voltage at the pump? Did you clip the leads on to the switch contacts and then operate
the pump so you could observe the voltage under operating conditions?

If not then the V test was not valid. If there are poor connections or inadequate wiring ANYWHERE in that circuit there will be too much V drop which will cause poor [slow] motor operation causing slow pumping action and ultimately early motor and switch failure.

I am not arguing against another pump but many people do not understand that a check for this must be done under loaded conditions looking for excessive Vdrop.

The pressure switch on a Jabsco Variflow pump does not handle the current of the motor, that is done in the controller. The pressure switch is just a signal to the controller.

The Marco controller seems much better at regulating pressure, and has the same built in safeguards as the Jabsco without all the false alarms they are known for. The only problem I had with them is in my RV, the pump is above the tank and I had tiny vacuum leaks in the pump inlet line (the Marco supplied inlet filter was responsible for this) causing it to lose prime. Also, the water system in the RV - a truck camper - is very small, which could confuse the pressure regulation loop in certain circumstances causing a slight sag in water pressure before the pump came up to speed. Not a problem on a larger water system (more volume to dampen pressure waves) and cured with the addition of a small accumulator tank.

Got it

I will clean and inspect the pressure switch/sensor this weekend and hope that clears a jam interfering with the sensor operation.

I also ordered a Marco UP3 pump directly from Marco for US $170. Feels like a real bargain.

HeadedToTexas said:

I will clean and inspect the pressure switch/sensor this weekend and hope that clears a jam interfering with the sensor operation.

I also ordered a Marco UP3 pump directly from Marco for US $170. Feels like a real bargain.

Click to expand...

that's less expensive than i would have thought. please post a review of the performance after you install it.
i have a variable speed jabsco and i feel like i'd like better performance than it gives. i was thinking of installing the larger one, but $170 is a small price to pay if the 3 gpm works well.

The Sensor Max pumps use a magnet that is moved out under pressure at the end of the pump into the path of a hall effect sensor. This now controls a PWM controller with a single FET power transistor to drive the pump motor at what ever speed it needs to meet it's pressure goal. The Hall effects go bad, but that usually results in no pumping action at all. The power FET shorts and that will allow the pump to run at full speed and eventually trip the breaker. This sounds more probable. I have fixed mine in the past, and so far have been ok. The Hall effect sensor is/was out of production. The part number is A1321 by Allegro. I would have to go back and review my notes for part number of the power FET, but they were easily obtainable. The failure mode seems to be a tank that runs dry, that allows the pump to run full trying to make pressure. The transistor then overheats due to poor heatsinking and the fact that the motor itself just starts to run hot. The transistor shorts the low side of the motor to ground and the pump just runs full out. At least that is how mine failed. Faucet wasn't fully tightened and the pump was left on. They do really work well when they work, but it wasn't one of the "better" designs. I guess it could have been, but maybe it would have cost an extra .10 for a timer circuit or a thermal monitor to shut the thing down if the transistor got too hot?

Steve

Vicki Z

Got fed up of the unreliability of modern sensor pumps, and their sensors. I now have mine controlled by https://www.amazon.com/gp/product/B07Q6WBNCV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Have had 2 1/2 years of trouble free use since i did the conversion ($20 switch $5 for brass tee and bit of cooper pipe) 30mins labour. It may not be speed controlled etc. But pumps against the membrane tank and has worked flawlessly. I feel that sometimes these people invent upgrades to increase sales, and the KISS principle is far better option.