Detecting water flow?

[MHotchin]

Greetings! I have a Hot Water recirc system that I can control from C4 - I have the motor on a switch. Right now I turn off HW recirc at night.

Has anyone set something up to detect when water is being used, i.e., there is flow in the water pipe? Then I could have the granularity much finer, and only turn on the recirc if water is being used.

[CFUG]

I did this in the beginning. It costs pracitcally nothing to run this pump full-time. Save your money on a C4 Outlet Switch and a flow Switch (a few hun to be exact).

[MHotchin]

It's not just the pump, there's the cost of the hot water losing heat to the house, and having to make it up using electric heat.

Bad enough in the winter (expensive heat, but at least useful), just plain awful in summer.

[CFUG]

I'm assuming that you are in need of a flow switch and not a flow transmitter. You're not going to get much "resolution" as C4 does not take-in analog sigs but you can trigger the pump based on flow switch sig on a HC or IO extender.

Are you dealing with a pump at the HWH or at the point-of-service? I really don't see Control4 helping here as some pump controllers already incorp. flow sense, scheduling, etc...

[RyanE]

The point of the recirc pump is to have the hot water where you want it *before* the person turns on the taps.

Now, if you had motion sensors in the bathrooms, you could use that info to turn on the recirc when someone enters the room, but it doesn't make much sense to me to turn it on when they've already turned on the spigot.

RyanE

[fredpenner]

Use a flow transmitter with a current switch to trigger a input on a c4 contact. You can pick what you need up pretty cheep used on ebay, but setting up industrial automation is a little much to ask from a c4 dealer. You need to find someone who understand instrumentation to give you a hand.

[MHotchin]

For my purposes, recirc on flow would work fine, since 'most' of the time, cold water is used before hot water is needed - flush toilet, turn on recirc, etc.

For those few other time, the recirc pump gets hot water around the system quite fast, so the delay is not a big deal. Filling the sink with dishes? No problem, I'll need enough water anyway.

I was really looking for a simple, flow 'Yes / No' detector - on flow, close a contact. Trivial to integrate with C4.

[CFUG]

Let me re-state, you can get a cheap flow switch and do the detection. But, it won't work well the way you are describing. You have a lot of themal mass in those pipes to be raising the temperature the minute you start flowing.

Have you really looked at your cost of just running the pump during morning and late evening hours? Flow switches and flow measurement are not really needed