Iwaki Md 70rlt And Heat Issues

[edat]

I recently added this pump to run on a closed loop for my 75 gal.
I had to relocate my tank in my house so all fish corals and inverts were in a separate tank so nothing was harmed.
I set up the tank in its new location, filled with water, turned on new pumps and left for work.
When I was able to start on restocking the tank the next day I realized that the water was a little warmer....A LOT WARMER...95 :eek2:

I thought external pumps ran cooler than internal.
Anyone else had this or heard of this happening ??

[JetCat USA]

I've got several Iwaki's and they have a little heat transfer but not to that extreme, if it's the pump you've likely got a bearing problems causing excessive heat in the case that's transferring to the impeller housing.

[aninjaatemyshoe]

External pumps do not run cooler, if anything they run hotter than submersible (powerhead) pumps. However, they will usually add less heat to the water than a submersible pump of the same wattage. This is because the excess heat generated from the pump can go into the air instead of the water. Iwakis in general run pretty hot, but they don't usually add that much heat directly into the water. However, this can be a problem if say your pump is right next to the tank and the air around it is pretty stagnant. I'm assuming this is the case. An Iwaki 70rlt will definitely generate alot of heat, but this can be managed if it is placed remotely or if you ran a fan over it. Personally, I think doing both is a good choice. If you are already running it remotely and it is causing this issue, I would say that you have something wrong with your pump. Of course, how much did it actually raise your temp? I know it is at 95, but what temp is it without the pump running?

Another possible issue is that you're running the American motored Iwaki, which is inferior to the Japanese one; adds more heat, less efficient, noisier. Though this wouldn't cause that much of a heat issue.

[JetCat USA]

<a href=showthread.php?s=&postid=10526948#post10526948 target=_blank>Originally posted</a> by aninjaatemyshoe
External pumps do not run cooler, if anything they run hotter than submersible (powerhead) pumps. However, they will usually add less heat to the water than a submersible pump of the same wattage. This is because the excess heat generated from the pump can go into the air instead of the water. Iwakis in general run pretty hot, but they don't usually add that much heat directly into the water. However, this can be a problem if say your pump is right next to the tank and the air around it is pretty stagnant. I'm assuming this is the case. An Iwaki 70rlt will definitely generate alot of heat, but this can be managed if it is placed remotely or if you ran a fan over it. Personally, I think doing both is a good choice. If you are already running it remotely and it is causing this issue, I would say that you have something wrong with your pump. Of course, how much did it actually raise your temp? I know it is at 95, but what temp is it without the pump running?

Another possible issue is that you're running the American motored Iwaki, which is inferior to the Japanese one; adds more heat, less efficient, noisier. Though this wouldn't cause that much of a heat issue.


i have to disagree with most of that post, external pumps have their own built in fan and most aren't even warm to the touch (such as the ReeFlo's), I've got an Iwaki 40RTL crammed into the stand of my 75g (90g volume) with all sorts of cords/surge protectors and the transformers from my two Tunze streams pilled on top of it and it's not even warm to the touch, tank temp is steady at 75º. the motor case on my ReeFlo Hammerhead running a CL on my 180g is cool to the touch.

if that's been you're experience with external pumps, it sounds like you've had some bad pumps too.

http://i16.*******.com/4mn69g7.jpg

[edat]

Thanks for the responses!!
The pump is located 30 inches below the tank in the stand.
The temp of the tanks ranges from 79 to 81 max with 2X250 mh.
I do have the one with the Japanese motor...at least that's what is written on the pumps sticker.
If it is bearing problems is that easy to fix?
I also have an Iwaki 40RT on a separate closed loop on the same tank it it gives me no heat issues at all.

[aninjaatemyshoe]

JetCat,
The one Iwaki I've ran sofar is a 2MD 20RLT. It is in perfect working order, but as a 2MD model (2 impellars/volutes) it does not have a fan. It heats up, but this doesn't become a problem because my pump is not sitting right next to my tank. Perhaps the lack of a fan is why these guys aren't so popular... In any case, I'll take your word that other Iwaki's are sufficiently cooled by the fan they have. Edat, It seems likely that your pump has a bearing problem.

However, it is the case that external pumps (mag-drives) generate more heat per watt than submersible (powerhead) pumps. Just compare the wattages of two such pumps of similar flowrate/pressure ratings. Again, this does not mean that externals add more heat than powerheads to the aquarium unless the heat has no where else to go. Just because you have yours crammed into the stand with stuff piled up on it does not mean that the heat is entering the tank. I'm talking about having the pump right next to the tank in a near completely confined space where the heat has no where else to go.

[JetCat USA]

<a href=showthread.php?s=&postid=10528259#post10528259 target=_blank>Originally posted</a> by aninjaatemyshoe
..........it is the case that external pumps (mag-drives) generate more heat...............

a Mag drive pump isn't an external pump, it's a submersible with the option to be run external, a sealed power head, and I've never called them a water pump myself, they are water heaters that happen to provide flow as well. probably one of the worst pumps there is to heat the water regardless of if it's ran external or not.

also, my stand is confined, has a back and doors, and the sump is sitting a 1" PVC union away from the pump. you've got the wrong impression about external pumps and not to be taken as flaming you it sounds to me like you have very little experience with external pumps.

[aninjaatemyshoe]

You're confusing what I call mag-drive pumps with the crap pumps made by Danner Supreme (which incidently is a powerhead and not a mag-drive). Mag-drive pumps are pumps in which the impellars are magnetically coupled with a larger magnet that is driven by a motor. They are not submersible because their design does not water-proof the motor. Submersible (powerhead) pumps are pumps in which the impellar is driven by electrical coils that are encased in epoxy. The coils are energized and generate magnetic flux that causes the impellar to rotate. I do know what I'm talking about. If you were to look at wattage vs. flowrate of mag-drive pumps vs. powerhead pumps, you would notice that mag-drives use higher wattage to pump the same flow. This means more heat. Again, powerheads submersed tend to generate more heat than mag-drive pumps because the heat has no where else to go. If your Iwaki pump is not hot to the touch, the heat is escaping effectively. If your tank is not heating up, then the heat is going somewhere else (out of the stand and into the surrounding room). I don't feel the need to argue thermodynamics/heat transfer any more on this one.

[JetCat USA]

edat

I'd recommend pulling the pump apart and inspecting that the cooling ports aren't blocked with salt creep/dust/etc..... or that the fan isn't slipping on the shaft. they also build up dust in the back fan cover which restricts air flow.

only way to check the bearings is to spin the fan by hand, it should spin freely with no drag other then the slight bumps from the magnetic fields.

aninjaatemyshoe

while the Iwaki is a magnetic driven pump, not all externals are as you are trying to classify them, most are direct drive. you are right that there is no need to argue with you about it, i stand behind my previous statement that it's my opinion you have little experience with external pumps in general.