Dolphin MC789 chiller only 23*C

[ksc133]

hi folks,

i got hold of a 2nd hand Dolphin MC789 chiller (2 Fan model) to cool my 30 liter tank.
but i can only get average of 23*C running non-stop for 2 days already.

i am using a 17W 855L water pump to pump into the chiller.

1) is this 17W pump producing too much heat?
will replacing a smaller watt pump help to bring down the temp?

what other ways can i help to bring the temp to 22*C

thanks

[dexter]

hi bro, may i know what is your surrounding temperature? i got a friend who uses the same chiller but only manage to get around 26+ degree on a 1 feet cube tank. How did you acheive 23 degree?

[ksc133]

hi bro,

my ambient temp is ard 30-28*C.

ya the original dolphin MC789 chiller sucks!!!
because the heat sink and 70mm fans are too small.
i touch the surface after running 12 hours, it was burning hot.

Not wanting to throw it away, i went to SLT to buy 2*120mm fans and
a BIG 330mm*120mm aluminium heat skin.

all i did was to mount it on top (with thermal grease of course) of the original dolphin 2*75Watts peliter TEM.

i run again for another 24 hours and this morning 10am, it was 22.5*C i can see water condensation on the tank surface. i am not lying or joking.
but by mid afternoon sun 3PM it rose to 24*C....

average temp it was around 23*C like now at 9.45PM

but i seriously need to cool it to 22*C for my animals.
i was thinking if my 17W water pump was producing too much heat???

thanks bro

[wllm33]

this is interesting on your part.
think most complain of this dolphin "chiller"is cos it drops the temp too little.
most likely it is the fan size from what you described.

mind sharing how you connect the fan to the original tem peltier.
i don't mind if i can get 23 degC already.
thanks

[teebs]

I somehow don't think that a 17W pump is producing so much heat that it can heat up your 30L aquarium by 1 degC. I think it would be more likely that your lighting is the one that is producing the heat that is increasing the temperature of your water.

But just curious, how much did you spend on the heat sink and fans from SLS???

[teebs]

Anothing you could try is to get an external pump instead of the submissible pump you are currently using. This is if you are really sure your pump is producing the excess heat that is raising your aquarium temp by 1-2 degC.

[ksc133]

hi folks

thanks for all your advice.
the BIG heat sink cost around $15 and the fans at $15 each at sim lim tower.
i use soldering to joint back to the original peliter TEM.
ya i change the 17W pump to 6W pump and still 23*C

i am now thinking of mounting the chiller directly on the tank top or sides.
my tank is plastic... drilling..lolz and sealing with silicon...
this method eliminate the use of water pumps and water pipes which might cause COLDNESS lost.

was also thinking the design of heat sink is not good enuff.
looking at some 2nd hand copper heat sink for servers etc...

cheers!

[ksc133]

hi folks,

i read on this thread.
http://www.arofanatics.com/forums/sh...620&highlight=

looking at specs of dolphin MC789 150/180W
it should be able to deliver around "93W will give Qc = 53.1W (model CP1-12706)"

to cool from 30*C to 22*C, Qc needed is around 90W

so clearly Dolphin MC789 should be able to cool to 22*C from 30*C.
but some how it just cannot go lower than 22.5*C

any experts can advice?

thanks

[charonstix]

Wow bro, managing to get a 23 deg average is already very good. What fauna are you keeping that requires 22 deg? Nice DIY by the way, maybe can post some pictures of ur modification?
By the way i believe that the dolphin tem can be fixed such a way that the peltier contacts with the water directly. (stated in the setup paper) You might want to try that arrangement?

[ksc133]

hi bro,

i was keeping some pets...they need 20-22*C.
earlier i did not use any chiller at 27*C ...1 die liao... sad!!!
i quickly put in fridge at 15*C for 1 week before i setup this chiller. they 2 remaining are ok now so far.

i will post the pic when i back in office cos now no usb cable to connect to my phone cam.

yes, the dolphin has 2 model internal and external.
i tried mounting my external model on top of the tank but cold fins was too short..lolz....

but i have to say it was not really worth to spend $45 extra to modd the dolphin.
unless u can get MC789 at $50. lolz
or u can find spare unwanted powerful fans and BIG heat sink to modd it.

[teebs]

If you really want to get that additional cooling power, you can:

1) Insulate your tank.
2) Insulate your inlet & outlet pipings
3) use a clip on fan to blow your water surface/lightings to disperse the heat
4) dismantle the peltier elements from your chiller and mount them on the sides of your tank
5) If your setup is a fresh water setup, then make a lot of ice cubes and throw them into your tank each morning and at night.

[wllm33]

if so much modification is needed to get your desired temperature, perhaps investing in a small chiller may be better.
just a thought.

[ksc133]

hi folks

some pics of my dolphin modd

[BFG]

hi folks,

i got hold of a 2nd hand Dolphin MC789 chiller (2 Fan model) to cool my 30 liter tank.
but i can only get average of 23*C running non-stop for 2 days already.

i am using a 17W 855L water pump to pump into the chiller.

1) is this 17W pump producing too much heat?
will replacing a smaller watt pump help to bring down the temp?

what other ways can i help to bring the temp to 22*C

thanks

Is that a full 30 liter container or a 30 liter container half filled? You could go with an external pump.

[ksc133]

thats a 57cm*37cm*15cm tub.
roughly 32 Liters.

if fully filled with be 55-60 liters i guess.

external pump is X leh
i got my 6W 420 Liters submersible pump at $12

[teebs]

Why are u using a plastic tub and not an actual aquarium?

The only other cheap way for you to get your temp down is using ice cubes. Another alternative would be to increase the efficiency of your Dolphin TEM cooler. You could do it by using a fan to blow at your Dolphin cooler.

[vinz]

If you really want the temperature to drop, get an external pump. But then, how much will it drop?

[deacon]

Why are u using a plastic tub and not an actual aquarium?

The only other cheap way for you to get your temp down is using ice cubes. Another alternative would be to increase the efficiency of your Dolphin TEM cooler. You could do it by using a fan to blow at your Dolphin cooler.

But he already "upsized" the fans

[teebs]

But he already "upsized" the fans

Yes, he did but a stand fan at 16" is much larger than the fans he is currently using...

[Wahlin]

Yes, he did but a stand fan at 16" is much larger than the fans he is currently using...

16" fan to cool down heatsink or peltier, not quite practical right.