Help rewire chiller

[NaTe R]

i need some help.

i have a chiller with its own temperature controller that turns it on and off but it is 1.5 degrees off what the actual temperature is in the display. Plus it cools for too long and temp swings 2 degrees in an hour to an hour and half if i don't manually turn it off. so..

this is what i want to do i want to re wire it so when power comes on to the unit it turns the chiller on and when power is cut it kills it.
I want to hook it up to my ReefKeeper Controller that is far more accurate.

here are some photos of what the guts look like.

picture of the units temp controller

picture of the wiring coming in the side of the unit

hand drawn schematic of wiring. Dont know what the "unknown box" is i was hoping sombody out there can look at this and tell me what wires to cut and splice and so on

if you need any more info please let me know

 

[ac7av]

I am a refrigeration and air-condition tech.
I may be able to help but the question I have is.
Do you want the controls on the chiller to still be operational after the mod?
If not you can easily hook it directly to your controller. My only concern with the direct connection is if the controller tries to turn the compressor on too soon you may have a currant overload and destroy your control. A compressor can not just turn on and off like a light. The computer on the chiller probably has a delay circuit prevent this from happening. BTW the unknown box is a run capacitor for the compressor.

 

[NaTe R]

Do you want the controls on the chiller to still be operational after the mod?

NO

My only concern with the direct connection is if the controller tries to turn the compressor on too soon you may have a currant overload and destroy your control.

i have a "safe-start" Feature on my controller that tell the controller to delay turning the power back on after it has turned it off for 10 minutes (i think 10 min might be 15min).
It is the function used when the controller run metal halide lights, to not let them immediately fire back up. So this shouldn't be a problem.

Thanks for the help, what should i cut?

 

[ac7av]

Does the control on the chiller remember its settings when you unplug it?
If it does then you could easily and with no modifications and still have the computer doing is job and operate your chiller with the control you have. Simply set your chiller for a low temp and let the controller control the operations of the chiller. For example set the chiller for 70 deg so it will not turn off before the controler if you have the controller set for 78 deg. With these settings the controller will tell the chiller when to turn on and off and if for some reason you have a short cycle the computer on the controller will prevent the compressor from turning on too soon.

 

[NaTe R]

Does the control on the chiller remember its settings when you unplug it?
If it does then you could easily and with no modifications and still have the computer doing is job and operate your chiller with the control you have. Simply set your chiller for a low temp and let the controller control the operations of the chiller. For example set the chiller for 70 deg so it will not turn off before the controler if you have the controller set for 78 deg. With these settings the controller will tell the chiller when to turn on and off and if for some reason you have a short cycle the computer on the controller will prevent the compressor from turning on too soon.

it does not remember the setting so i when i plug my chiller the way it is currently. the controller will turn it on and the chiller asks me what temperature i want it to turn on at. I tried this already and with the units controller the way it is, i am going to have to bypass it i think, and let my Reef keeper do the thinking

 

[jrgilles]

On my neptune apex controller, you can program it so that if it shuts off, it must remain in the off state for a given time period before it can turn back on. This would stop it from turning the compressor back on too soon. The syntax for the Apex is as follows:

Min Time 030:00 Then OFF
##the outlet will be kept in the OFF state for 30 minutes before it is allowed to be turned back on.

Here's another example:
Min Time 002:15 Then ON
##the outlet will be in the on state for at least 2 minutes 15 seconds before it can furn off.

Both a Min Time ... Then ON AND a Min Time ... Then OFF can be specified for each outlet.

Taken from the apex manual....

rob

 

[ac7av]

Okay if your controller has a safe setting on it then lets take a look at the wiring. Does your chiller have an actual wiring diagram on it that you can take a picture of to be sure the wires you drew are correct?

If not then lets talk about the drawing.

Only two things you need to look at

The compressor and the cooling fan.

Remove the white wire from the temp controller fan connection

Remove the white wire from the temp controller compressor connection

Remove the brown wire from the temp controller.

Connect to brown wire from the temp controller the two white wires you just disconnected from the temp controller

At this point you can leave the black wire of the fan connected to the temp control like it is or remove it and cap it off to completely isolate the temp controller.

This will remove the temp controller of the chiller completely from the system and allow you to use your external control to operate the chiller and still keep all internal fuses and power switch in operation.

 

[ac7av]

Sorry type O
Connect the brown wire from the temp controller to the two white wires you also disconnected from the temp control.

 

[ac7av]

Okay so I guess is late.

just cut off the white, red, and brown wire from the power supply board on the first picture and wire nut them together and you done. Plug it in turn on all the switches and your chilling.

 

[NaTe R]

Does your chiller have an actual wiring diagram on it that you can take a picture of to be sure the wires you drew are correct?

I will double check my drawing before i cut anything but i drew it because there is no diagram available. i m sure i mapped everything i had to cut some zipties to really see for sure where the wires went.

Okay so I guess is late.

just cut off the white, red, and brown wire from the power supply board on the first picture and wire nut them together and you done. Plug it in turn on all the switches and your chilling.

is that your final answer? LOL:lol:

 

[NaTe R]

jrgilles - Thanks, it would be nice to have the minimum on cycle duration controllable, i cant say weather mine has that feature or not i need to play with it and find out.

 

[ac7av]

I know I was thinking the same thing
Man I cant make up my mind.
I just was looking over your drawing and didn’t notice you made the wire transition at some terminal from white at the compressor to red at the control board but didn’t label it red so I just didn’t pick up on it at first. I see some really crazy diagrams in the field so if it doesn’t say it, I never guess it.

I’m sticking to the cut red, white, and brown. Connect them together and your done. If the diagram is correct. I cant really tell much from the second picture as far as the wiring goes to tell if its accurate or not but it looks good on the diagram.

 

[NaTe R]

ac7av I will tear in to this project after work tomorrow and let you know how it goes thank so much for your help.

Those Yellow Circles represent connections made by a four hole snap together harness thingy. it is strange that red connects to white and such but thats the way the communists built it i guess.

 

[Scooterman]

What is the controller relay out rated for, can it handle the chiller amperage? It looks like it is a 120 vac right? I guess your controller has a Temp. probe also?

 

[NaTe R]

hey scooter, the controller has a 15 amp breaker in the 4 outlet strip currently running 4.7amps max and the chiller will draw 2 amps is what it says on the side of the case. should be good there.

oh and the controller is has its own 20amp circuit it is plugged in to

And progress... well i forgot to grab some stuff out of my work van and left it on a job site so i will have to try and remember tomorrow.

 

[ac7av]

It should run it fine. The only time you need to worry about is the start up of the chiller. It probably has another currant rating on the label. If it has a rating of 15 or higher you may be overloading it. Most residential refrigerators even though not very power hungry appliances these days, run at give or take 90 – 150 watts when they are running. Not very much power is it. The manufactures and home building codes still say to hook them to individual 15 or 20 amp circuits. The reason for this is the start up power required by this type of devise. It can in many cases exceed the power rating of the circuit its connected too but its usually just for an instance. Having it connected to a circuit that has any substantial power drain on it from some other devise can be a problem in the long run.

 

[Scooterman]

My 1/4 HP chiller had an inrush of over 22.5 amps but ran at 6.5 amps. So I take it you have a small chiller which should be way easier to deal with.

 

[NaTe R]

i have a 1/5 hp chiller.

well i got home kinda late today from work and i was going to get this thing figured out but i thought to myself i had better get this controller thing figured out first being i was replacing my vho's outlet to the chiller and there lays the problem.

The settings on my Controller (reefkeeper) are weird the manual says that i can should be able to set my temp set-point, and how much variance in temperature it can move before it turns off. The Variance set point is good but, The set temp, (i want to keep my display) is only letting me go max 9 degrees. for example i can only adjust up from 0.00 not 000.0 like normal temperature setting on this thing. like it wants to control ph or somthing.

so i got to get a hold of DA and find out whats going on here before i do this thing. sounds like a great project for a Friday night.

 

[Scooterman]

You should shoot at least a 2 degree swing, don't try go go any less this will make the chiller work much harder.

 

[NaTe R]

What is the controller relay out rated for, can it handle the chiller amperage? It looks like it is a 120 vac right? I guess your controller has a Temp. probe also?

sorry scooter just saw this. The relay is rated for 8amps and it is 120 vac. and Yes i have a temp probe