Need help with JBJ chiller

[mikepclo]

Ooops just saw this reply. Thanks Blind River Joe for your help. Hope the 2 degrees swing wont have any negative effects.

Thanks again!

Originally Posted by Blind River Joe

Hello:

Just a bit of back ground. I am a refrigeration (HVAC Tech) by trade so I will try to answer you questions as best as I can.

Temp swing: If the thermostat is set to turn the unit on at 78of then that is when you chiller should start. There is usually what is called a deadband built into the thermostat of the chiller usually around 2 to 3 degrees. I.E. if you set the chiller to turn on at 78 and you have a 2 degree deadband the chiller will turn off at 76. The deadband is necessary because you just can't get that tight a temperature control at .2 degrees. Another reason for the deadband is to prevent what we call short cycling. Once the chiller turns off the refrigerant cycle requires time to equalizes pressure. Not going to go into all that but turning a compressor on and off very quickly is a good way to end it's life.

Your clunking sound when you move the chiller is the motor inside the compressor. The compressor motor is mounted on springs and when you move the chiller the motor (Inside the black dome looking item) hits the side of the casing. Normal to sometime hear this when you move the unit but not okay if it is clunking when the chiller is not being moved and the unit is running. Be gentle when you move the chiller. You may also hear a clunking sound when the chiller shuts off. Once again normal.

Pulsing hum not the normal constant hum not sure what you mean by pulsing hum. What are you comparing the noise to?

In you last question 3 minute load time... If I understand correctly you are using some other type of temperature sensor to turn you chiller on and off?? Here is how I run my chiller. The chiller is on a heavy duty programmable timer. It turns on at 8 am and off at 4:30 pm Monday to Friday. Sat and Sun on at 9:00 am off at 12:30 pm on at 3:00 pm off at 430 pm. My chiller has it's own temperature sensor built in to it just like your and cycles on and off as required as long as the heavy duty timer is energized. Hope this helped you out.

[gregzz4]

I ran a different brand of 1/4 chiller on my freshwater 125g
I set the differential to 3 degrees
If it was set to 2 degrees, it would short-cycle;
Chiller would only run for about 45 seconds, and would run every 4 mins

With it set to 3 degrees, it would run for about 4 mins and roughly about 4 times/hour
The tank temp was 78F and I never saw it fluctuate, even with the 3 degree differential

My current chiller is a 1/10 on my 75g, with a total of 110g of water
My RKL runs the chiller with a differential of only 0.4 degrees and everything is fine
RKL turns on the chiller, takes a few minutes to power-cycle and sense what is going on, turns on and runs 'till RKL shuts it off
I have the chiller set to 77 (with a 2 degree differential) and run my tank @ 79, so the chiller will always turn on when powered up
Maybe this will fry the chiller processor, but it's worked fine for a year so far
HTH