Do I need an over temperature safety sensor for my UV unit?

I don’t know, it depends on what you’re using your UV unit to do. I’ll give you some creative solutions in which you would need one fitted. If you have the situation I describe or a similar one then you may need one.

An over temperature safety sensor or TSS, is simply a thermometer that reads the fluid temperature in your UV chamber. The temperature isn’t shown to the user on the display but the temp levels can be set by the individual.

In our first scenario, you only use the unit for a single, large application (We’ll say your rain water harvester for arguments sake) but your use is intermittent (there is only flow through your system when rainwater is being processed), where there will be the same water sitting in the UV unit for a while, the lamp will have enough time to heat this water up. This is OK up to around 40°C, after that you’d be looking at burning hot water coming out the other end that can damage the UV unit, things in your pipe work setup and more importantly ‘little Timmy’ who turned the tap on. A TSS will detect that the water is getting hot and at 40°C will activate automatically. Once it gets back to an acceptable temperature the lamp will be switched on again.

Scenario 2. My water is pumped from a borehole to my moderately sized home. In this situation I would not recommend

a TSS. If your pump breaks you will once again have that water sitting in and heating up your UV unit, but because the power of that lamp is likely to be quite low, it won’t be able to heat the water hot enough to do any damage.

The 2 types of and actions that a TSS will do when activated are:

Lamp off type– Will switch the lamp off when over temperature is reached and back on when the temp is      safe again.

• Pros– No wasted water
• Cons– Can potentially allow untreated liquid through when the lamp’s off

Dump Valve –  Will open a valve that lets fluid through, it can either be connected to a recirculation loop or just left open to run off into a drain.

• Pros – No chance of contaminated fluid passing through because the lamp never                               switch
• Cons – Can only be installed on a pressurised system

What type of TSS you would need depends on your application but there is a definite answer for every situation. You will need one or the other.If you’re curious as to which one you need or if you have the right one, ask me. I’ll know J 

And sorry about the picture, I couldn’t resist.