Choosing the right chiller

[Sfiorenzo]

Hey all, Im fairly new to the hobby and have noticed that I nees to add a chiller to my Tank setup, left unchecked, my temps are approaching 84 degrees unless I keep the AC at 70 degrees.

What is your experience with chillers? Did you install undersized or oversized? I see lots of equipment for aqua/hydroponic chillers so is the tank size the same? Does pump size matter in the long run once your temps are stable? ( side note on this one, I am wondering if I can run my overflow line through the chiller on its way to the sump in the basement.

I would love to hear tips and generalities so others may gain insight as opposed to specific details on how my tank is set up.

 

[Tanggy]

I bought my chiller b4 the summer heat started. I bought one that is one size bigger than my tank size in case I might get a larger tank later on. Each chiller has a min/max flow rate through them. I have mine going from the return pump through my chiller and into my DT. I avoided having another pump in the sump. For the summer it kept my temp between 76-77 degrees. I have it set at 77 degree and it turns on when it hits 78.1 and turns off when it goes down to 76.8. For me, being in southern CA, it's a pretty good investment so far.

 

[Sfiorenzo]

Did you include your sump in your volume measurements?

 

[jda]

Include total water volume... it will all be running through there. I would size the chiller appropriately, but not too big or too small. Short cycling can be hard on refrigeration units, but running for a long time can be as well.

Pay attention to the max flow. The best way to run them is to have the return pump go through the chiller and the output into the tank. If you have a external controller, then have the temp probe in the tank... if the chiller has an internal thermostat, then so be it.

If you can, have the chiller outside, in the garage or storage room or something... they do put off heat like an AC unit does.

Before you buy a chiller, have you tried good fans? I do not mean computer or DC fans, but something like a Vornado. They can really help.

 

[Dan Korczak]

I subscribe to the theory that it’s better to over-size than to under. I’d rather more frequent cycles than a longer stint, but I also like the flexibility of reusing the chiller for a larger future project.

 

[Tanggy]

Did you include your sump in your volume measurements?

Yes. Total water volume.

 

[jda]

I forgot to mention that if you get a chiller with an internal thermostat, then do not get it too big or else the display can get cold before the water gets all the way through the sump and into the chiller. This can lag. If you have the controller temp probe in the tank, then this does not matter at all.

Even if you have a chiller with an internal thermostat, it is not a bad idea to dual control it with a Ranco. You just need to be sure that the chiller will "remember" the settings when the Ranco cuts the power. I have used dual Rancos before with the second one set a degree different than the first... but I have never had a ranco fail, so I kinda stopped doing this. I have had other temp controllers fail and especially the ones inside of Oceanic, Coralife, etc. units.

 

[CoralCache]

You almost never want to pay attention to the max flow to the chiller because at the temps we run our tanks at it is almost always way too much.
I have repaired and design/built many chillers and the recommended flow rates I see on mass produced units are high. I have installed many with the minimum recommended flow area but I take the temp of the suction line while it is running with water through the barrell. A very rough range would be a line temperature between 50 and 60 degrees. If the line temperature is above 70 degrees you will likely shorten the life of the compressor because of excess heat in the compressor motor windings.
When I build a chiller I match the flow of water to refrigerant pressures and temperatures. If you have an ac buddy it is always a good idea to ask them to pull the cover and see what they think.