Manufacturer recommended flow rate thru chillers?

[AcroporAddict]

Guys,
Each chiller make has a factory recommended flow rate for the chiller.

How many of you have actually measured net flow thru your chillers, and how does this line up with the factory recommended rates?

I just installed a Pacific Coast Imports 1/2 horsepower chiller/heater, and the recommeded flow rate thru the chiller is 750 gph minimum-1500 gph maximum. Chiller has 3/4" inlet/outlet. I have a dedicated Mag 12 pump that runs water from the intake side of the sump to the chiller, then back to the return side of the sump. The Mag 12 has 3/4" outlet fittings, and all tubing is 3/4". The length of tubing from the Mag 12 to the chiller is about 6 feet, and the return to the sump from the chiller is about 4 feet.

I did a net flow measure by holding the return tubing over a 5 gallon bucket for 30 seconds, and only got a flow rate of 360 gallons an hour from a Mag 12. Chiller sits right next to the tank stand. No real head height to speak of, with not a long tube run to and from the chiller.

A general rule of thumb (on Vendor websites) is that a chiller adds 6 feet of head height to a pump, but using the Danner flow chart, it is really more like 10 feet.

To get the recommended flow rate it looks like I'd have to go to a Mag 18 or an external pump, which seems ridiculous to me.

Another friend has a 1 HP Current Prime Inline chiller that he initially ran a Mag 12 (1200 gph) on as a dedicated pump, and it wasn't cooling, so he called Current USA and they told him to reduce the size of the pump because the water was flowing too fast to cool properly, even though the manufacturer recommended flow rating for this chiller is 1200-1560 gph. He now runs a 500 gph Eheim pump and the chiller works fine.

So needless to say I am confused. On one hand, for me to get the recommended flow rate thru my chiller I would have to go to a much larger pump because of the severe loss of flow, and then my friend is using a 500 gph pump on a chiller twice the size and was told by the manufacturer to basically ignore the recommended flow rate of their own chiller.

Any chiller owner's experiences to share with how they sized their chiller pumps?

My chiller works, but if I can use a smaller pump that uses less electricity I would do it. I am just at a loss over the recommended flow rate vs what people are actually doing.
Dave

[sjm817]

I've never run a chiller so dont have any real experience with them. IMO, a Mag is not a good choice for a pump. The flow ratings on a Mag12 are based on 1.5" plumbing. It loses a ton of flow using 3/4". It isn't really a good pump for high head. The other issue is it is a water cooled pump. The pump you are using to cool in the tank with the chiller is heating up the water. You would be better off with an air cooled external pump that can handle high head.

[AcroporAddict]

The chiller has 3/4" fittings, so the max ID the water will travel thru at any time is 3/4". There really is not an alternative to place an external pump. Most people use submerged pumps to run chillers anyways.

I appreciate your input, but my questions really refers to factory recommended flow rates vs what people are actually using and getting thru their own chillers.
Dave

[HighlandReef]

if it was me i would do what the manuf recommends, if they did their job the engineered it to a specific gph and i would not mess with it

[magikfly]

Have you actually tried running the chiller with the mag?
Sometimes you should just try and see how things work the way they are...
Don't get too worked up about the manufacturers ratings, in the end what works for you will be based on experience..