Maximum safe flow rate pump for Resun CL-280?

[pepetj]

The Resun CL-280 chiller manual specs states a minimum output flow rate for the waterpump/powehead as >900LPH.

I am currently using 1,400LPH powerhead submerged in a Wet/Dry filter to feed the chiller.

What is the maximum, yet safe, output flow rate for this unit? There's no such info in the manual. I guess there should be a safety upper limit.

If someone has run this unit -or a similar one- with 1,800-2,500LPH I would like to know about your experience.

Pepe
Santo Domingo

[Cookiemunster]

The Resun CL-280 chiller manual specs states a minimum output flow rate for the waterpump/powehead as >900LPH.

I am currently using 1,400LPH powerhead submerged in a Wet/Dry filter to feed the chiller.

What is the maximum, yet safe, output flow rate for this unit? There's no such info in the manual. I guess there should be a safety upper limit.

If someone has run this unit -or a similar one- with 1,800-2,500LPH I would like to know about your experience.

Pepe
Santo Domingo

Hi there,

there isn't anything dangerous about oversetting the flow rate except for poor temperature transfer.ie to put it simply, if the water flows too fast, there isn't sufficient contact time on the metal cooling surface in the chiller to chill the water.

On the contrary if the flow rate is too slow, the chiller would cut off thinking it has already reached the designated set temp as the water within its chilling cylinder is chilled very quickly.

So back to your question on maximum safe flow rate. Theres really none. Unless you seal the end of the chiller, it will not ever be at risk of bursting due to over flow rates typically. Unless you do something silly like put a 10000 LPH pump to it.

However, the recommended flow rate for effective cooling for the resun 280 would be about 1000LPH (take into consideration the number of turns or joints and height of your tank which will reduce flow rate also). But also remember that a resun 280 would only be effective for up to 2.5ft tanks. It would really be stressed (run almost continuously) for 3ft tanks.

Cheers

[pepetj]

Hi there,

However, the recommended flow rate for effective cooling for the resun 280 would be about 1000LPH (take into consideration the number of turns or joints and height of your tank which will reduce flow rate also). But also remember that a resun 280 would only be effective for up to 2.5ft tanks. It would really be stressed (run almost continuously) for 3ft tanks.

Cheers

Thank you very much. I have no idea where the recommended tank length info is to be found. For whatever (wrong marketing/sales?) reason(s) the Resun manual makes reference of tank's volume only.

Would the CL-650 be OK for a 4 footer, 40gal tank (consider 50gal if Wet/Dry sump is included)? I have few options down here (Santo Domingo) and there's one for sale.

I wish, if possible, to be somewhat cost-effective. Keeping the chiller running for as long as possible (to avoid so insanely frequent start-ups) but without ruining the unit's life either. I really appreciate you took your time to answer me, I posted a few weeks ago, so far I have found submersible pumps that I could use so the question is... Which range should I go try next? maybe 4,000LPH? or 6,000LPH?

By the way, the electricity bill showed a huge increment (above 200KW/hr for last 31 days), I can't blame just the chiller (I have added a 18W UV sterilizer, 2 airpumps, etc) but I know the frequent on/off/on cycles of the CL-280 has some accountability there.

Thank you very much CookieMunster

PS Would it be wise to adapt a DIY external thermostat?

I figure I can go for a couple of months paying the extra energy, but I need to find/implement a common-sense solution.

Pepe
Santo Domingo

[Cookiemunster]

No problem pepe,

I'm just sharing whatever I know.

There isn't much info about most non european chiller brands as they are quite sloppy in terms of data.

However, based on a typical 1/10hp chiller which the CL-280 is, you can roughly estimate it can easily chill down to 25 degrees a tank volume of up to 2x2.5x1.5ft tank.

If you get a 1/2hp chiller, you can easily chill down to 25 degrees a 2x2x4ft tank with a small sump tank.

Having said that, you would also need to consider any heat contributors such as super strong Metal Halide lighting in terms of watts. But if its just T5 or PL lights, then no worries as the heat transfer isn't much of a big deal.

The chiller location is also very important as the heat exchange via surrounding air circulation will greatly affect the performance of a chiller too. Ensure the intake side is cool air and the output side blows the hot air away from the tank. (I'm taking about the ventilation and not the water flow)

Submersible pumps you mentioned really depends on brands as the stated pump flow greatly depends on height and number of bends. Each bend reduces the flow rate by about 10%. Usually pumps will provide a chart which indicates the reduced flow rate at a certain height.(well eheims do)

However, for a 4ft tank, a flow rate of 3500 lph should be more than sufficient unless you want to create strong currents or have many bends or the flow height is more than 6ft about pump level.

Try not to overkill on pump flow as thats a big wattage consumption as it has to run 24hrs by 7.

Resun typically has a very very inaccurate thermostat. So if you really want an accurate temp to be maintained, you can install a thermostat to the input voltage to the chiller so that the thermostat is used to activate the chiller (turn on/off). However your chiller has to be set at a much lower temperature so that it will not affect your external thermostat. (ie set chiller to 20 degrees and external thermostat to 25 degrees)

If you have a current meter clamp type, you can accurately measure the current consumption of the chiller and effectively calculate exactly how much wattage (Current x voltage) your chiller is using. see http://en.wikipedia.org/wiki/Clamp_meter

Typically its a balance of on/off/on cycles or duration of each on and off cycle. The most efficient state would be more off than on durations of course. There is a short current spike each time a chiller kicks on but it doesn't contribute to cost as much as length of on duration. Think of it in terms of an aircon.

Also factor in

1) how many degrees less the surrounding air temp you wish to set.
2) Good air circulation to remove hot air
3) Good match of chiller horsepower to volume of water to be chilled.

Cheers

[pepetj]

Just to close this thread:

I upgraded the powerhead rated at 1400LPH (Resun SP-2500) for a submersible pump with adjustable output, rated at 6000LPH (Resun Flow-6000).

Start-up/turn-off time: 45 minutes (give or take 2 minutes). off/re-start: >60 minutes.

Pepe
Santo Domingo