UV sterilizer is causing interference on temp probe

[MrCaveman]

I just finished installing a 57w UV on my tank redo and the UV is causing rapid temperature fluctuations. The UV only comes on at night however it's causing my chiller to turn off and on every 30 seconds since the apex reads a high temp then 0.4 degree temp change turns the chiller off; then right back to a high temp. I'm worried this will damage my chiller and or heater.

I know for sure it's the UV causing this because during the day when the UV is off, the temp is very consistent and gradual.

I've tried moving the temp cord as far away from all parts of the UV and covering the UV and ballast with a towel trying to absorb interference with no luck. What can I do? It would be a shame to have to program my chiller and heater off at night since temperature is such a basic and crucial parameter to stay consistent.

I've thought of wrapping the whole temp probe wire in aluminum foil to reflect the interference, which I think is ridiculous if I have to do it. What can be done to solve this besides permanently removing the UV or programming off my temperature control?

 

[vhuang168]

Does the output of the UV exit near the temp probe?


Sent from my iPhone using Tapatalk

 

[kurt_n]

Seems like the best way to deal with it is along the lines you're trying... reduce or eliminate the electrical interference. I don't have any input on how to do that, but I'm sure some of the electrical engineering type folks will offer suggestions.

One thing that jumped out at me though was your comment about the 0.4 degree swing causing things to turn on/off. While it doesn't eliminate the fluctuations, you could loosen up whatever your setpoints are for the heater and chiller. Having a 1 to 2 degree swing isn't going to be detrimental to the system. What are your setpoints for the heater and chiller controls?

Personally, I've always questioned the effectiveness of UV on our tanks anyway, and wonder whether you really need it to start with.

 

[jepuskar]

My UV power brick caused my flow meter to stop working when it was within 12" of it. I don't doubt this behavior for anything else electronic nearby.