Chiller Size Suggestion!!!

[taichimaster]

I have a 75 gallon with a 20 gallon sump. I am currently running a Pacific Coast 1/10 chiller. Never had a chiller before, so I was watching it and noticed that it is running 15minutes then off for 5 and on for 15 again....and off for 5 minutes and so on. Is this considered a short cycle? Is it undersized? I have two 250watt halide in an enclosed canopy. I was just wondering if this is undersized and if it will be costing me lots of energy. your suggestions are appreciated.

 

[taichimaster]

Another note,
I don't think it is a lack of flow because I am running a nEheim 1262 that is rated at 900 gph. the Pacific Coast 1/10 is suggested for 500-800gph.

 

[kimo4848]

I would run a 1/4h. I'm running one on a 120 + 30g sump and same lighting as you are. My chiller runs for 10min at a time about 3 to 4 times a day and that is in the summer months.
Ken

 

[Herefishyfishy]

Add some fans, chiller shouldn't need to be running this time of year

 

[trido]

I recently went through the same thing setting up my 1/3HP Pac coast chiller. If its running for 15 minutes then shutting off for only five then IMO its short cycling. If the chiller has done its job, it will not be turning back on after only five minutes because it is extremely unlikely that the tank is heating up the two degree differential in only five minutes.
I for example, have a chiller rated for 600-1000GPH. First I ran a mag7 which was far too small. Then I ran My mag 12 but had too much pipe friction and head loss. Both methods caused a short cylcle much like the ones your experiencing. I replumbed it again wiht the mag 12 and the chiller worked well but I didnt like the plumbing lay out for my over all system so I replumbed it once again. Now, my chiller seems to have too much flow and doesnt seem so be working as well as it did with the third layout.

Good luck finding the happy medium.

 

[trido]

Add some fans, chiller shouldn't need to be running this time of year

I wish I could agree with that statement. My system is pretty intense and Im still working out some bugs.

Here fishy is right. A couple of low wattage fans in the hood and over the sump will do wonders. I ran my 120 with 250s for three years without a chiller with no problems

 

[taichimaster]

Thanks guys. I am running the chiller with flex pipe and at a very short distance. no elbows. I will add some fans and see i guess.

 

[Scooterman]

sounds like your return may be too close to where the drain water is going to the chiller suction.

I'm all for increasing pipe flow one or two sizes bigger than what the pumps require but in this case I think the chiller is getting some of that cooler water in it too soon & you need to separate it enough to allow the entire tank water to be cooled down. One other issue If you have an external probe then it need to be placed in the main tank opposite of that return also for the very same reason.
I'm a fan of fans but in this case it I'd fix the problem first. Really you may be ably to get by with just fans but that is another subject, fix the issue first then re-think the use of fans to reduce the amount of run time on that chiller if needed at all.

The suction for that chiller should be in the sump before Or the actual return & the outlet should be in the main tank & away from the suction or drain to the sump as far as possible.

 

[mfinn]

Another note,
I don't think it is a lack of flow because I am running a nEheim 1262 that is rated at 900 gph. the Pacific Coast 1/10 is suggested for 500-800gph.

By changing to a slower flow pump, the water should get colder in the chiller and lengthen the time before the chiller starts up.
I'd go with a pump at the middle to low end of the flow requirements.
Along with the other suggestions, something good should happen.

 

[trido]

By changing to a slower flow pump, the water should get colder in the chiller and lengthen the time before the chiller starts up.
I'd go with a pump at the middle to low end of the flow requirements.
Along with the other suggestions, something good should happen.

I dont want to argue Finn but............
I recently spoke to a rep from Pacific coast imports regarding my new chiller.
He explained that the only problem with running too much flow through their product was less effiency like your describing. This will cause the chiller to run a very long time and not cool the water much at all. But if you have lack of flow, cooling the water in the coils too fast then the chiller basicly gets tricked into thinking the water in the tank is cold. The temp will drop from 79 down to 77 in a matter of ten minutes or so, (In my case it was more like 5min on/2min off) then only a few minutes later, with the tank water running through it it heats back up to the real temp and kicks the chiller on again. Thus, the short cycle.
He also said to me that he hears all the time (speaking about the bigger unit) "IM running a mag7 on it, Thats 700GPH, I dont see what the problem is". He claimed that people dont take into account for head loss and pipe friction. Not that this is the case here. Tachimaster seems to have a fine pump for the job. I think that scooterman may be onto something.
I tend to wonder how much restriction there really is in the coils of these chillers we use and wish that the manufactures could give us a little more guidance regarding set up and flow vs. pump ratio.

I guess Ill have to tear into my chiller to see first hand to get a better idea. :evil:

 

[taichimaster]

thanks guys for all the info. I did some tinkering and got another thermometer to test my tank temperature. It read at a steady 78.4 degrees. I then figure that there might be something wrong with the internal temp controller. I went and recalibrate the unit. let's see if this helps. I will post updates after watch it for a while.

 

[mfinn]

I dont want to argue Finn but............
I recently spoke to a rep from Pacific coast imports regarding my new chiller.

Good information is always welcomed.
I learned something myself.

 

[taichimaster]

Well,
I am still having this chiller problem. I diagnosed it and Scooter is right on track with the return being too close to the drain on my return pump. The chiller is getting some of the cold water from the drain I would guess. Unfortunately, there isn't much i can do inregards to adjusting the plumbing. hard to explain, but replumbing is not an option. I currently have a reef keeper with the temp probe in the tank. I have the chiller connected to the reefkeeper but the chiller temp controller is overriding the Reefkeeper controller. Is there a way to disable the chiller temp controller and use the Reefkeeper controller instead?

I have a Pacific Coast CL-280 1/10hp Chiller.

 

[RGibson]

taichimaster what is the tem of the room that the tank is in?

 

[trido]

Well,
Is there a way to disable the chiller temp controller and use the Reefkeeper controller instead?

Turn the chiller temp down to 75 or 76 so it will either run until it believes it has reached the desired tank temp, or the secondary controller turns it off. I would suggest turning it even lower if necessary but if the primary controller fails you run the risk of chilling your tank to death. Literally. I had to set mine at 75 to insure it ran properly at first. Now that the flow issues are worked out it works like a charm .

 

[taichimaster]

I have it in the basement. It is actually pretty cool. I would say 68-70 degrees.

 

[taichimaster]

Trido, I might try your suggestion. I will first try 77 on the chiller temp controller. I have the Reefkeeper set at 78. We will see.