Problems with pumps

The KH Director is a good tool to measure and control a very important parameter in reef aquaria, such as alkalinity. In general is a well designed monitor, but I have to complain about certain components. The peristaltic pumps, which are virtually silent, a very important feature, are prone to errors due to quick deterioration. I do not know whether is a design problem or cheap materials, but I am experiencing problems with several heads of the same doser that I had not never experienced with any of the two dosers I have been using for years (the black old models). In addition to that, the internal pump, which was also virtually silent at the beginning, now makes a loud noise when it begins to work at each measurement. I suspect I'll have to open the unit and make some adjustments, as happens with the faulty heads.

I wish GHL could solve these problems in the near future. It's a shame that a well designed, valuable and expensive piece of equipment has these problems, that require continuous attention and maintenance.

Hello,

You mention pumps, but do not specify exactly which pumps you are referring to; KHD mixing pump or Doser pumps.
Without this information, diagnosis is difficult.

Please create a support ticket and provide additional details on your setup.
We can then assist you further.

Hi Vinny. I'm referring to both. Pumps no 1 and 3 of the doser 2.1 that comes with the KHD and the KHD mixing pump which is making an ugly noise when it starts to run.

Have you removed these blue caps to inspect and/or clean?

I was actually going to start my own thread but mine is so close to this I hope the OP does not mind me joining in. Please have this deleted if necessary. Here is mine, specifically...
I have fought all the issues that everyone else has with my KHD, bad reagent, air in the tubing... my internal circulation motor went out and my unit was replaced. I am in the technology field and I get it. I have looked inside the unit, and I am very impressed for a piece of equipment designed for the aquarium. Still when my unit is running, it is wonderfully accurate and I do love it but it can be a little frustrating.
Here was yesterdays events that led to this...
My new unit (KHD) had been running for a couple weeks, dead on.
Yesterday I saw a spike from 9 to 10.1 I watched it. Each run, it climbed a point or two higher. obviously had an issue. At lunch when i went home I checked with my Hannah. they normally match and now the KHD was high.
I ran a manual KHD and watched. Head #3 failed. I pulled off the head cover (old style) and the internal guide in the cover was chipped. I blew out the head with canned air and the rest looked good. Vinny had sent me 4 new style covers, (post office destroyed 1) so I popped on a new one (my last one) and started to go thru and reset the KHD. I didn't take into consideration that they internal capsule had not fully been drained and when I went to flush the measurement cell, the cell overfilled draining into the vent tube. This in turn soaked and ruined the inline air filter. I removed, opened and inspected the unit. I let the unit incompletely drain. I removed the vent tubing, removed the air filter and reinstalled the vent tubing. I reassembled and reinstalled the unit.
I ran another manual test. Head #1 failed. I thought this can't be, it's a new style head. Upon removing the head cover it was obvious what the issue was. The head cover was fine, no damage. The internal hose was very flat from running 6 times per day, every day plus all the running for calibrations and dialing in. Lots of black dust in the cover and on the rollers. I replaced all of the internals, new tubing, new rollers and new pizza roller guide. I again went thru setup. It took a couple of times to dial things in but I am now up and running again, dead on. Here are some of my observation and actually gets to my main question. Sorry this has been so wordy.
1. From what I can tell, the heads on the pumps are different from the old style and even the European design. The heads rely on the tight tolerances of all components, tubing, pizza guide, rollers and head cover. There is no "gearing" or "direct drive" Any failure, even the eventual flattening of the tubing can cause a lack of fit and the the whole head to fails. Is this correct? If so, what would be the expected life of the internals? How often, running at 6 times per day, do I need to remove the cover and check for wear. I believe the screws for the caps are just going into plastic and that will probably wear. Maybe just the tubing replaced on a regular basis, failure or not?
2. The new head covers are "Fast". They must be re-calibrated. One of my pumps is now actually 10 mls/min faster then it ever has been. All increased with the new covers. It is also visually obvious when running that they are smoother and faster.
3. You just gotta remove that air filter.
4. I need more parts! :-) Also, stock the screws. Tiny and difficult to handle. I keep a fish net with neodymium magnets in it to find and retrieve them when dropped.
Jeff



Comments or criticism?

Yes, I have removed the blue caps several times and adjusted the white cilindres. After doing that the pump works fine for several days and then, suddenly, one day it stops working. However I have not inspected the internal pump yet. Is there something you can do with this internal pump to eliminate the noise?

Quote:

---

Originally Posted by Shredded

1. From what I can tell, the heads on the pumps are different from the old style and even the European design. The heads rely on the tight tolerances of all components, tubing, pizza guide, rollers and head cover. There is no "gearing" or "direct drive" Any failure, even the eventual flattening of the tubing can cause a lack of fit and the the whole head to fails. Is this correct? If so, what would be the expected life of the internals? How often, running at 6 times per day, do I need to remove the cover and check for wear. I believe the screws for the caps are just going into plastic and that will probably wear. Maybe just the tubing replaced on a regular basis, failure or not?
2. The new head covers are "Fast". They must be re-calibrated. One of my pumps is now actually 10 mls/min faster then it ever has been. All increased with the new covers. It is also visually obvious when running that they are smoother and faster.
3. You just gotta remove that air filter.
4. I need more parts! :-) Also, stock the screws. Tiny and difficult to handle. I keep a fish net with neodymium magnets in it to find and retrieve them when dropped.
Jeff

Comments or criticism?

---

Hi Jeff,

1. The screws themselves will not "wear out". The only parts that will wear overtime (depending on usage) are the blue cap, rollers, and tube. The tubes should last you quite a while. A good replacement indicator is when the tube begins to harden, crack, or become more yellow. Personally, I like to replace these at least once a year. The caps and rollers should be regularly cleaned every 3-6 months. The key is to make sure you're not accumulating excess dust because that will eventually put more strain on the moving parts and motor.

2. Since these v2 caps are sturdier and slightly different from the originals, re-calibration may be necessary.

3. Yes, we found that some users encountered issue where the filter would become clogged and result in trapped air which blocked the VENT. After looking into this some more, we decided to no longer include these vent filters because they did not provide much more of an added benefit.

4. We'll take this into consideration. :)

Quote:

---

Originally Posted by chema61

Yes, I have removed the blue caps several times and adjusted the white cilindres. After doing that the pump works fine for several days and then, suddenly, one day it stops working. However I have not inspected the internal pump yet. Is there something you can do with this internal pump to eliminate the noise?

---

Noise is going to depend on a few things:

• Presence of dust inside cap and around rollers
• Set speed of pump motor

When you run the pump at slower speeds, more noise will be produced naturally. This is the typical behavior of stepper motor pumps. Higher accuracy and speed adjustment at the cost of slightly more noise when run at slower speeds.

Jeff,
Looks like you went through hell with your unit. Sorry to hear then man..Hows accuracy on you unit? I am having issues my self, much lower reading vs lamotte test kit..

Mike

I have had the same problem with the Doser 2.1. The heads wore out after only a couple of months.

Hi Vinny, there is something I don't quite understand. The pump producing the noise is the internal pump, the one mixing the sample water with the reagent in the internal cell. Can you modify the speed of this pump? If so, how do you do it?

Quote:

---

Originally Posted by Shredded

I was actually going to start my own thread but mine is so close to this I hope the OP does not mind me joining in. Please have this deleted if necessary. Here is mine, specifically...
I have fought all the issues that everyone else has with my KHD, bad reagent, air in the tubing... my internal circulation motor went out and my unit was replaced. I am in the technology field and I get it. I have looked inside the unit, and I am very impressed for a piece of equipment designed for the aquarium. Still when my unit is running, it is wonderfully accurate and I do love it but it can be a little frustrating.
Here was yesterdays events that led to this...
My new unit (KHD) had been running for a couple weeks, dead on.
Yesterday I saw a spike from 9 to 10.1 I watched it. Each run, it climbed a point or two higher. obviously had an issue. At lunch when i went home I checked with my Hannah. they normally match and now the KHD was high.
I ran a manual KHD and watched. Head #3 failed. I pulled off the head cover (old style) and the internal guide in the cover was chipped. I blew out the head with canned air and the rest looked good. Vinny had sent me 4 new style covers, (post office destroyed 1) so I popped on a new one (my last one) and started to go thru and reset the KHD. I didn't take into consideration that they internal capsule had not fully been drained and when I went to flush the measurement cell, the cell overfilled draining into the vent tube. This in turn soaked and ruined the inline air filter. I removed, opened and inspected the unit. I let the unit incompletely drain. I removed the vent tubing, removed the air filter and reinstalled the vent tubing. I reassembled and reinstalled the unit.
I ran another manual test. Head #1 failed. I thought this can't be, it's a new style head. Upon removing the head cover it was obvious what the issue was. The head cover was fine, no damage. The internal hose was very flat from running 6 times per day, every day plus all the running for calibrations and dialing in. Lots of black dust in the cover and on the rollers. I replaced all of the internals, new tubing, new rollers and new pizza roller guide. I again went thru setup. It took a couple of times to dial things in but I am now up and running again, dead on. Here are some of my observation and actually gets to my main question. Sorry this has been so wordy.
1. From what I can tell, the heads on the pumps are different from the old style and even the European design. The heads rely on the tight tolerances of all components, tubing, pizza guide, rollers and head cover. There is no "gearing" or "direct drive" Any failure, even the eventual flattening of the tubing can cause a lack of fit and the the whole head to fails. Is this correct? If so, what would be the expected life of the internals? How often, running at 6 times per day, do I need to remove the cover and check for wear. I believe the screws for the caps are just going into plastic and that will probably wear. Maybe just the tubing replaced on a regular basis, failure or not?
2. The new head covers are "Fast". They must be re-calibrated. One of my pumps is now actually 10 mls/min faster then it ever has been. All increased with the new covers. It is also visually obvious when running that they are smoother and faster.
3. You just gotta remove that air filter.
4. I need more parts! :-) Also, stock the screws. Tiny and difficult to handle. I keep a fish net with neodymium magnets in it to find and retrieve them when dropped.
Jeff



Comments or criticism?

---

There is something somehow implicit in your observations and that is worrying me. If the speed of the dosing heads depends upon the type of head cover, that may mean that a worn out cover changes the speed of the dosing head. Then, you would have variable speeds depending on the degradation degree of the cover, which would modify the sample volume and the reagent volume resulting in differences in the measurements.

I have observed that from time to time the KHD gives an alkalinity lecture quite different from the ones previously observed. Then, the following ones may be again in range.

Quote:

---

Originally Posted by chema61

There is something somehow implicit in your observations and that is worrying me. If the speed of the dosing heads depends upon the type of head cover, that may mean that a worn out cover changes the speed of the dosing head. Then, you would have variable speeds depending on the degradation degree of the cover, which would modify the sample volume and the reagent volume resulting in differences in the measurements.

I have observed that from time to time the KHD gives an alkalinity lecture quite different from the ones previously observed. Then, the following ones may be again in range.

---

Not sure if I can reopen this thread or not. I actually did not see this last post previously but I share the same concern that that has the heads wear, tolerances will change and at the very least need to be recalibrated as the amount dosed is going to change. The reason for revisiting this is because this weekend I took down my KHD and it's respective doser for inspection and maintenance. I have ordered parts from my LFS because I am still down one head (borrowed the cover) from a previous failure and wanted a spare. It is now going on 3 weeks and my LFS has not received the parts that were ordered. During the cleaning of the heads on the doser I discovered two of the heads were damaged as before. My concern about this is that they were the new stronger heads, so apparently even tho they last longer, they are still going to fail. I opened a ticket on the GHL ticketing system on Sunday but no one has responded. I rebuilt all the heads with the best of the damaged parts, also borrowing from my other doser to get this one back up and going. I'm not sure what to do here. Am I just going to just have to rebuild the heads every 3 to 4 months? The other thing I noticed is even tho the new heads broke exactly like the ones before, same location, they didn't stop working. This is good and bad. The KHD didn't stop functioning, but the damaged head covers pretty much just ate up the rollers which in turn, damaged the tubing so it was a full rebuild on the damaged heads.