DOS Repair

[2mk]

Has anyone attempted to repair a Neptune DOS before? Please join my thread for suggestions and advice for all fellow reefers facing the same problem?

 

[2mk]

The DOS I used for Automatic Water Change failed me big time after being in service for some 18 months. The left stepper pump motor failed without warning while the right stepper motor was working fine. There were no alerts whatsoever.

Since the DOS left pump was used to add water, while the right DOS pump was used to remove water, guess what had gone really wrong? Salt water was pump out of my tank without water being replaced. What made things worst was my Automatic Top Off added plain water to the tank to replace water "lost" for a more than 24 hours period while I was away from home. It almost created a catastrophic thank failure. Long story short, let me get to the point. The warranty period expired and I don't want to spend $300 for a new unit. I have been trying to repair my DOS to no avail.

After opening my DOS and researching on the internet, I have come up with the following info:

The picture I took after opening the DOS is above. The motor details are shown on stepper motor the label. I found a stepper motor on AliExpress for $65.00 that appears to be the same motor with the same specs but does not show the entire model number. Noted that it is from the same motor manufacturer. "

250ml/min, 4 Rollers, 24V Honlite Stepping Peristaltic Pump with Exchangeable Pump Head and PharMed BPT Peristaltic Tube"​

US $65.0 |250ml/min, 4 Rollers, 24V Honlite Stepping Peristaltic Pump with Exchangeable Pump Head and PharMed BPT Peristaltic Tube|peristaltic pump|pharmed bptpump pump - AliExpress​

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com


I am almost sure the problem with mine is a motor lock-up problem. I took the motor out and tried to disassemble it by removing the 4 screws show on the back of the motor to no avail. Nothing came apart. Then I force it to turn and it turned with a lot of effort. After re-installing it back in, It worked for a few minutes and ceased to work while making the same grinding sound, while the right motor right motor works fine.

@MadeForThat I wonder if the above can be used as a replacement. Can you or anyone take a look at it and give me an opinion?

@MadeForThat Can You comment on my new thread as to whether the above is an exact stepper motor replacement?

Also can you contribute / commented on your other post concerning "I toyed around with replacing the dos stepper drivers with something more modern"?

 

[Joe31415]

Before you replace it, swap the wiring harnesses. So if you try to turn the right motor, the left one spins. Turn the left one and the right one spins. See if the problem follows the motor or the wires.
What should happen, if you have a bad motor, is that the bad motor still won't spin and the good one will spin. This will verify the motor is indeed bad. However, if the 'bad' motor now works and the good one doesn't, then the problem lies somewhere between the connector and the controller. Whether it's just a bad connector or a problem with the circuit board or a problem with the apex, we'd have to figure out later.

This is just a quick a very quick test to confirm the motor is bad. You don't want to spend $65 and wait 2 months for it to ship from China just to find out it wasn't the problem.

PS, if you do this, label the motors (good/bad). Once you start moving things around, you're eventually going to forget which one is which.

 

[Mical]

What are the chances you can send it into Neptune for repair? (IDK is why I asked...) Have you called Neptune? Granted it probably won't be warranty but getting it fixed should be less costly vs new replacement.

 

[2mk]

Before you replace it, swap the wiring harnesses. So if you try to turn the right motor, the left one spins. Turn the left one and the right one spins. See if the problem follows the motor or the wires.
What should happen, if you have a bad motor, is that the bad motor still won't spin and the good one will spin. This will verify the motor is indeed bad. However, if the 'bad' motor now works and the good one doesn't, then the problem lies somewhere between the connector and the controller. Whether it's just a bad connector or a problem with the circuit board or a problem with the apex, we'd have to figure out later.

This is just a quick a very quick test to confirm the motor is bad. You don't want to spend $65 and wait 2 months for it to ship from China just to find out it wasn't the problem.

PS, if you do this, label the motors (good/bad). Once you start moving things around, you're eventually going to forget which one is which.

Good idea. I have not thought of that one yet. I will swap the motors' position and test to see if it's one of the motor's or the board's problem and report back.

 

[2mk]

What are the chances you can send it into Neptune for repair? (IDK is why I asked...) Have you called Neptune? Granted it probably won't be warranty but getting it fixed should be less costly vs new replacement.

A new DOS will cost me $299 here in the US. Sending it back for repair will cost me $75 plus shipping to Neptune from Neptune's reply if that's the problem. So it would come out almost the same. But, I was thinking what if the other motor fails too after the repair? So do I repair it again? If I were to get 2 or more motors instead 1 (i am sure the other one will fail soon too), than the shipping would come out less. In that scenario, I might be better off cost wise, especially on down time. That's why I hesitate on sending it in. Did not buy the motor because I am not sure if it's exact replacement. It sure looks identical. The $65 motor includes the pump head unit. The pump head unit I think cost $29.99 to buy online.

It's Just a thought. What you think?

 

[Joe31415]

Good idea. I have not thought of that one yet.

I actually read the OP a few times to make sure you didn't mention it. It's one of the first things I would have done, especially considering that it appears as though there's more than enough slack in the wires to make it really easy to do. But, I'm a troubleshooter by nature, it's what I do.

Anyways, moving on. The model number on yours is HSP-24-250-NPT-2-P, the AliExpress one you linked to is HSP-24-250-NPT-4-T-PO.
The biggest difference being that yours has 2 rollers and theirs has 4. I don't have a DOS (or an Apex or anything by Neptune) but presumably when you calibrate the new motor/head, that will be compensated for.
The "O" at the end of their model number is the color. It's orange, so it should match, or at least be close.
The only other difference is the T, which stands for 'external tube'. I'm not sure what they mean by that. It might just have to do with the matieral the barbed fittings are made of (PVC). I probably wouldn't let that part be a deal breaker for me. There's always a way to make a tube connect to another tube.

The only part that I'd really be concerned about is that the DOS driver can drive this stepper. I don't know enough about the technicalities of stepper motor drivers to be able to answer that. If this part is wrong and $65 won't break the bank, I'd say go for it. Especially if you can find another use for the motor at some point. Stepper motors are handy, but you'd have to either buy a driver or build/program one with an Arduino or Raspberry Pi. Come to think of it, since it comes with the rollers and tubing, you could use it as an ATO or another dosing pump. And on top of that, if you've never played with a Raspberry Pi or Arduino, it's a nice little skill to pick up and not all that difficult, and for how powerful they are, they're really, really cheap. A Raspberry Pi can be had for like $50 and is essentially a fully functioning computer.

EDIT: If you're not comfortable with gambling $65, I'd either bite the bullet and get a new one (or find a used one (here/craigslist,ebay) or send yours in to be fixed.

 

[ca1ore]

I have no particular wisdom to impart .... but am interested to see how you do this . I replaced a motor on my GHL with a manufacturer sourced spare part, but so far have not had to fiddle with my DOS. I'd be surprised if the DOS motor/dosing head were anything other than a standard OEM item.

 

[2mk]

I actually read the OP a few times to make sure you didn't mention it. It's one of the first things I would have done, especially considering that it appears as though there's more than enough slack in the wires to make it really easy to do. But, I'm a troubleshooter by nature, it's what I do.

Anyways, moving on. The model number on yours is HSP-24-250-NPT-2-P, the AliExpress one you linked to is HSP-24-250-NPT-4-T-PO.
The biggest difference being that yours has 2 rollers and theirs has 4. I don't have a DOS (or an Apex or anything by Neptune) but presumably when you calibrate the new motor/head, that will be compensated for.
The "O" at the end of their model number is the color. It's orange, so it should match, or at least be close.
The only other difference is the T, which stands for 'external tube'. I'm not sure what they mean by that. It might just have to do with the matieral the barbed fittings are made of (PVC). I probably wouldn't let that part be a deal breaker for me. There's always a way to make a tube connect to another tube.

The only part that I'd really be concerned about is that the DOS driver can drive this stepper. I don't know enough about the technicalities of stepper motor drivers to be able to answer that. If this part is wrong and $65 won't break the bank, I'd say go for it. Especially if you can find another use for the motor at some point. Stepper motors are handy, but you'd have to either buy a driver or build/program one with an Arduino or Raspberry Pi. Come to think of it, since it comes with the rollers and tubing, you could use it as an ATO or another dosing pump. And on top of that, if you've never played with a Raspberry Pi or Arduino, it's a nice little skill to pick up and not all that difficult, and for how powerful they are, they're really, really cheap. A Raspberry Pi can be had for like $50 and is essentially a fully functioning computer.

EDIT: If you're not comfortable with gambling $65, I'd either bite the bullet and get a new one (or find a used one (here/craigslist,ebay) or send yours in to be fixed.

Thank you for the detail insight and finding out the difference concerning the two motors. So the two are not exactly identical after all.

With 2 versus 4 rollers, does it mean the white color rolling (tube touching) part inside the orange pump head unit?

So might the "NPT-4-T-PO" part of the number describe the orange pump head, while the "HSP-24-250" describes the motor?

The "250" part I think they meant by 250ml as described in the specs, which is the same as the original DOS part.

I have read some info on the internet about people building their own "Tank Computers" using Raspberry PI. I have never played with a Rasberry PI, but I have always wanted to try it. Thanks again for the advice and great insight. I will have to make a decision on it at some point, or completely do away with the DOS. Right now I have been doing manual water change the old way for a couple of months since it broke down.

 

[2mk]

I have no particular wisdom to impart .... but am interested to see how you do this . I replaced a motor on my GHL with a manufacturer sourced spare part, but so far have not had to fiddle with my DOS. I'd be surprised if the DOS motor/dosing head were anything other than a standard OEM item.

Given if the stepper motor can be driven by the DOS driver, then it should be just a plugging in the new stepper motor process requiring not much but a screwdriver and re-plugging in harnesses.

As @Joe31415 pointed out in his previous reply, we don't know if the DOS driver can drive the motor unless we risk trying it.

I wonder if anyone had bought this motor and did a replacement repair with it that worked.

 

[infinite0180]

Yea thats just the roller in the head. That most likely the exact same pump. People have bought those 4 roller heads as an upgrade. They snap right on...

 

[Joe31415]

Yea thats just the roller in the head. That most likely the exact same pump. People have bought those 4 roller heads as an upgrade. They snap right on...

And, now that I think about it, as long as the shafts on the two motors are the same, OP could probably just re-use the existing DOS head.

So might the "NPT-4-T-PO" part of the number describe the orange pump head, while the "HSP-24-250" describes the motor?

The "250" part I think they meant by 250ml as described in the specs, which is the same as the original DOS part.

HSP-24-250-NPT-4-T-PO means:
HSP=Honlite Stepping Peristaltic (Pump)
24=24 volts
250=250 ml/min
NPT=National Pipe Thread (the standards the threading uses, it's like asking if a bolt is Metric or Imperial)
4=4 Rollers
T=type of tubing that, I think, it's shipped with. It appears to mean Tygon S3 E-LFL, I'm sure whatever you have on hand is fine.
P=Peristaltic
O=Orange

I don't see any exact matches, at least not by Honlite. The one you found appears to be the closest. If that's who's making them for Neptune, it's possible there's a deal in place where Honlite isn't allowed to sell the identical one...they have just about every other variation, just not 2 rollers at 250ml/min driven by a 24V stepper motor.

Also, coming back to this "So might the "NPT-4-T-PO" part of the number describe the orange pump head, while the "HSP-24-250" describes the motor"
P-NPT-4-T-PO [the inital P is the last letter from HSP, 'pump'] describes the head, but the 250 would as well, or at least when coupled with that motor. Remember, all the motor does is spin. It doesn't know if there's a pump head or a 3D printer or a robotic arm doing microsurgery attached to it. It's told how how far, how fast and in which direction to turn and it does that.
A better way to look at is that HSP-24-250-NPT-4-T-PO describes the entire assembly. Especially since you'd need more than just HS-24 to describe the motor, that's just a brand name (Honlite), type of motor (stepper) and the voltage (24vdc).

 

[2mk]

And, now that I think about it, as long as the shafts on the two motors are the same, OP could probably just re-use the existing DOS head.


HSP-24-250-NPT-4-T-PO means:
HSP=Honlite Stepping Peristaltic (Pump)
24=24 volts
250=250 ml/min
NPT=National Pipe Thread (the standards the threading uses, it's like asking if a bolt is Metric or Imperial)
4=4 Rollers
T=type of tubing that, I think, it's shipped with. It appears to mean Tygon S3 E-LFL, I'm sure whatever you have on hand is fine.
P=Peristaltic
O=Orange

I don't see any exact matches, at least not by Honlite. The one you found appears to be the closest. If that's who's making them for Neptune, it's possible there's a deal in place where Honlite isn't allowed to sell the identical one...they have just about every other variation, just not 2 rollers at 250ml/min driven by a 24V stepper motor.

Also, coming back to this "So might the "NPT-4-T-PO" part of the number describe the orange pump head, while the "HSP-24-250" describes the motor"
P-NPT-4-T-PO [the inital P is the last letter from HSP, 'pump'] describes the head, but the 250 would as well, or at least when coupled with that motor. Remember, all the motor does is spin. It doesn't know if there's a pump head or a 3D printer or a robotic arm doing microsurgery attached to it. It's told how how far, how fast and in which direction to turn and it does that.
A better way to look at is that HSP-24-250-NPT-4-T-PO describes the entire assembly. Especially since you'd need more than just HS-24 to describe the motor, that's just a brand name (Honlite), type of motor (stepper) and the voltage (24vdc).

Thank You again for a complete and more comprehensive explanation of the model number involved. From what you have explained so far, it seems like the motor might just work.

With the tubing, do you mean the soft rubber tube inside the pump head that is in contact with the rollers? Or external tubing they provide for use with the pump head?

 

[2mk]

Yea thats just the roller in the head. That most likely the exact same pump. People have bought those 4 roller heads as an upgrade. They snap right on...

You mean there are 2 types of pump head offered by Neptune? Or is it that people have bought the 4 rollers head not from neptune and used it on the DOS?

 

[infinite0180]

You mean there are 2 types of pump head offered by Neptune? Or is it that people have bought the 4 rollers head not from neptune and used it on the DOS?

Neptune cheaped out and supplies the two roller head offered by honlite. People have ordered the 4 roller heads, which were actually supplied by GHL for the Maxi doser until they stopped making that doser recently and poped it right on the DOS. Also vice versa.

 

[2mk]

Neptune cheaped out and supplies the two roller head offered by honlite. People have ordered the 4 roller heads, which were actually supplied by GHL for the Maxi doser until they stopped making that doser recently and poped it right on the DOS. Also vice versa.

That explains why the GHL dosers' pump head externally looks the same as Neptunes' pump head except for its blue color versus orange color.

The same company might be supplying the motor to GHL as well given if the pump heads are made by the motor company.

Very good info. Thanks.

 

[infinite0180]

That explains why the GHL dosers' pump head externally looks the same as Neptunes' pump head except for its blue color versus orange color.

The same company might be supplying the motor to GHL as well given if the pump heads are made by the motor company.

Very good info. Thanks.

I want to order the 4 rollers next time i need to replace mine! Avastmarine sells them separately because they used to sell a peri pump with the same blue head on it that GHL Maxi had. They actually went away from that design but kept the roller for their new model. I bet all these guys get them from the same source and build there own pumps with the same parts. Ive never seem a picture of the inside of a Maxi but id put $100 on it being Honlite and id even bet its the same specs as the DOS

 

[2mk]

@2mk As for the stepper motor, it probably isn't the motor unless the bearings gave out. If you open up the case it will have a sticker on the side that will have all of the requirements, and you should be able to find an exact replacement. If I had to guess it is a nema 17, but you will have to confirm with the name plate sticker or by measuring the "face" (with the shaft coming out) to see if it matches this:

nema stepper motors have standardized mounting faces, but the length "L" in the drawing changes depending on the amount of torque required.

I toyed around with replacing the dos stepper drivers with something more modern, as 3d printers have improved there has been a lot of development into silent stepper motors/drivers. the Neptune pcb does not lend itself well to this kind of modification, but if you were experienced enough, it surely could be done. @_AV if you can figure it out, I think a lot of people would love to pay for a service to have these stepper drivers hacked into their DOS..... I'd definitely be interested lol

@MadeForThat provided in his thread on EB832 that the motor might be a Nema 17. Any input from anyone who had used this to replace the stepper motor before? Will this be a compatible motor?

 

[MadeForThat]

I would recommend sending honlite a message and ask about your specific model required. If they bare the name on the pump, they will have a replacement. Seeing as Neptune clearly didn't design the pump, I would bet money that they cannot keep the manufacturer from selling replacements directly to customers. I would have said honlite might not sell individual units, and require a minimum order quantity, but that clearly isn't so, because they have an entire aliexpress store selling individual units lol.

To be honest I probably wouldn't bother trying to find a replacement motor, as the seller seems to allude that it is custom made or modified for the task of peristalsis. I would try to find the whole unit. It may end up costing you just as much as sending it in for service, but if you document your work, others can save a lot.

A slight bit of sacrifice on your part can save the community as a whole a ****ton of money. If you have this issue, 100 other people will also have this issue. If all 100 of those people went out and bought new DOS pump for $300 then the community as a whole just lost $30,000 to Neptune. When they could have just spent ~100 per person. ($10,000) Just making this thread and drawing attention to the issue of motor failure is awesome work @2mk in doing this you probably gave a lot back to the community already.

 

[MadeForThat]

Also I think it would be beneficial to request the admins make a sub forum for repairs for any and all equipment. Organized by manufacturer and product would be ideal to allow people to locate and fix their equipment.