U/V purifier

[Chucky_ott]

Hi all,

I want to install a U/V purifier at my cottage to make the water safer to ingest. Water source is from a shallow lake. Depending on the solution found, we might use bottled water for drinking but could still use the purified lake water for cooking, washing dishes, etc. We've been doing this for the last 30 years already with no issue but it's never too late to take more precautions. Ducks and geese (and fish) frequently swim close to the water intake on the lake.

Other than during my 3-week holiday, the cottage is used by me on weekends only. During other times, extended members of the family (wife, children, brothers, sisters, nieces, nephews) may come down and need water. So I need a user-friendly solution.

From what I have been reading, having the U/V purifier on for extended periods when there is no water flow may cause overheating and damage to the unit. Not sure if this is true or not. Solutions I have seen recommend using a flow switch (to power on the purifier only when there is flow) or a dump valve (to dump water if the temperature in the purifier rises).

I haven't done a lot of research into U/V units yet so I don't know if any of them have an integrated flow meter. Anyways, these are the options I'm considering and am wondering if any one has any insight. Maybe its a non-issue having the unit on all the time, other than reduced lamp life. Considering that it could stay on only for 6 months in a year, a lamp would potentially last 2 seasons.

Thanks

1. U/V purifier always on

Pros

Constant protection​

Cons

Electricity waste (not my primary concern)
Overheating of water in U/V device when not in use due to lack of water flow (could be 5-6 days).
Reduce life of unit (from what I've read), unless unit has built-in thermal protection.
​

2. Use a toggle switch (or timer switch) to control the U/V purifier

Pros

U/V unit on while switch toggled on​

Cons

May forget to toggle switch on when arriving at cottage - no UV protection
May forget to toggle switch off when departing cottage - unit stays on for extended period, even if not in use
When U/V lamp is off, bacteria can "swim" to downstream side of unit.
​

3. Use a toggle switch to control the U/V purifier and pump

Pros

U/V unit and pump on while switch toggled on​

Cons

Even with pump off, pressure tank (20 gallon tank) may have enough stored water (4-5 gallons) to supply users - no UV protection
When U/V lamp is off, bacteria can "swim" to downstream side of unit.
​

4. U/V purifier wired to pump pressure switch

Pros

U/V comes on only when pump comes on.​

Cons

Even with pump off, pressure tank (20 gallon tank) may have enough stored water (4-5 gallons) to supply users - no UV protection. Would work better with a small tank and a CSV
When U/V lamp is off, bacteria can "swim" to downstream side of unit.​

5. U/V purifier connected to an inline flow meter

Pros

U/V lamp only comes on when there is water flow​

Cons

Frequent cycling of U/V lamp - not sure if this is an issue
When U/V lamp is off, bacteria can "swim" to downstream side of unit.
​

6. U/V purifier connected to an inline flow meter with time delay (not sure if such a device exists)

Pros

U/V lamp only comes on when there is water flow. Lamp stays of for duration of delay, even if no flow.​

Cons

When U/V lamp is off, bacteria can "swim" to downstream side of unit.
​

7. U/V purifier connected to a temperature sensor

Pros

U/V lamp powers off when temperature rises (indicating no flow)​

Cons

none ?​

 

[Chucky_ott]

Found that at least one manufacturer makes a "temperature management valve" that goes on the UV purifier's outlet port. It will let about 1L-2L of water drain if the temperature exceeds 35C (I think). So option 8 -using such a valve - might be the safest and easiest option.

https://viqua.com/product/650537/