Water flow switch - shower to control ceiling fan

C

cmerlino

Member
I'm looking for a "reasonably priced" (whatever that is...) water flow switch I can put inline with my shower - hot water side, most likely. I want to turn on the ceiling fan when the shower is running.

I can tie the switch to an unused input on the Elk M1G, and then to ISY/Insteon from there, so any low voltage capable switch will do. What I have found, however, are all paddle type devices, and I'm concerned I will loose water pressure/flow - which I really can't afford in the shower.

Anyone have any experience with this?

Thanks!
 
:hesaid:

If the goal is to control humidity, the more typical and much simpler approach is to use a humidistat. You can get humidistats that'll trip a zone on your M1G or otherwise which can be used to turn the fan on/off.

Again, if it's humidity to control - the humidity takes a while after the fan is off to dissipate; I have a humidistat on the fan in my MBR and it runs for about 15 minutes after the shower is complete (but, I suppose you could do that with timing). Either way though, it's much simpler with the humidistat - and you can even get manual ones with no power required and hook them to a wireless contact if need be - making it extremely simple.

Otherwise another potential option that might work without altering your plumbing would be a temperature sensor strapped to your hot-water line. It won't be hot until the shower has been running, so that could work too... again it'd take a while to cool off though once finished.
 
Strapping a temp sensor may false trigger - depending on how hot the roof space gets. Here is Aus, our water is set to a max of 40 odd degrees (cold water mixed in at the tank outlet). A temp sensor will only get to 40 degree at most (less due to line losses).
Out summers reach into the 30's, and the roof space (where the pipes are) will be in excess of 60°C, so the M1 would think that the hot water is on.

As for it not turning off when the hot water is turned off, that ends up being a good thing. Most automated fans are set with a run on timer so that when you turn the loght off, the fan runs for a couple of minutes and then turns off. The pipework cooling slowly will achieve the same logic.

If you want to measure flow, look for an ultrasonic flow sensor. These strap on to the outside of the pipe and come in two varieties, a flow switch or a flow sensor (analog output).

Mick
 
I use HomeSeer and one of the $20 Oregon wireless temp and humidity sensors and an RFXCom receiver to control all of my bathroom fans. It works great and we never have to worry about turning the fans on or off.
 
znelbok said:
Strapping a temp sensor may false trigger - depending on how hot the roof space gets. Here is Aus, our water is set to a max of 40 odd degrees (cold water mixed in at the tank outlet). A temp sensor will only get to 40 degree at most (less due to line losses).
Out summers reach into the 30's, and the roof space (where the pipes are) will be in excess of 60°C, so the M1 would think that the hot water is on.
Click to expand...
The OP is in New Jersey, not Australia; and neither I or the OP said anything about an attic install ^_^

A temp sensor strapped to a water line in a wall cavity would work just fine... but I still prefer the humidistat.
 
Thanks for all the feedback. Was heading for flow sensing because it seemed more efficient to get the air moving before the humidity built up, rather than trying to clear it afterward. Just my logic (or lack of same...) Of course, the control would run for some fixed time after the shower stopped.

Haven't seen the ultrasonic flow switch - interesting....
As for the temp sensor strapped to the pipe - I think it would work fine, since it is a basement access to the pipe - no temp. extremes...

Thanks again to all !!!
 
Work2Play said:
The OP is in New Jersey, not Australia; and neither I or the OP said anything about an attic install ^_^
Click to expand...

Yes, I know you the OP is not in Aus , but I was using my situation as an illistration as to the downside to using a temp sensor to detect hot water - to make you think about it.

You didn't say it wasn't in the attic either - what am I, a mind reader...... :angry2:

Replies like this make me not want to help at all.
 
I do something a little simpler. I put a wireless door sensor at the top of the glass door, not very noticeable to most. Wrote program for Omnipro to turn on exhaust fan when "ready". Then to turn off 5 minutes after "not ready". We leave the door open when not used.
 
I put a motion sensor in the shower. When it triggers more than 3 times within a specified period (to allow you to reach in and get something out without triggering the fan), it assumes someone is in the shower. Then for me, the fan goes on, until 20 minutes after the room-door is opened. For my wife, it turns on for 20 min. after the door is opened (i.e. does not run while she is in the shower).

--Dan
 
About 20+ years ago, I put an exhaust fan in, with a delay on break timer. You turned the fan on and 15-20 minutes later, the fan turns off. Currently, the timer is flakey, because it is in the attic, but 20 years is a long life.

Switches are designed for specific flow rates, but there doesn't appear to be cheap ones around.

These are piston based: http://ecatalog.gems...tches/en/122340 so they don't really impead flow. You will also need a 50 micron particulate filter.

These are really nice: http://www.gemssenso...ng-rfs-cat.ashx, but are way to expensive. These require a 150 micron filter.

I've used both in an industrial environment with a filter.
 
Just to clarify though, this is all about running a fan to prevent humidity build-up, right? I still have to say the dehumidistat seems like the way to go. Why go through all the hassles guessing when to turn on and for how long rather than detecting the actual presence of the very humidity you wish to expel?

I was just about to go through all this in my master bathroom - install a UPB switch on the fan, and wire in a dehumidistat that would trip a zone on the Elk which would turn the fan on/off; all expensive and lots of work in the end... when my homebuilder offered, at their expense, to put in an automatic ceiling fan. It took the place of the old one; has a humidistat built-in, and uses all existing wiring. We leave the switch on all the time; and when there's enough humidity, it turns on; when the humidity is gone, it turns off. It's located just outside the shower door so it trips pretty quickly; and if I want it on manually, I just flip the switch off and on again. And - it's super quiet. Even if I'd paid for it myself, it would've cost less than a UPB switch and humidistat and wireless zone sensor, all to automate the previous noisy fan. Sometimes the simplest solutions really are the best!
 
Totally different approach.

What about hiding a water sensor in the drain line? GRI makes ones that are pretty cheap (about $13) and close a circuit when wet. If you wired them up to your Elk and whenever the zone became secure have it send an insteon signal to your fan. When the zone opens, let the fan run for five more minutes. If your shower is over a basement or crawl space it would be simple deal. If it is in a slab. . .well forget it.

You might be able to just drill two small holes into the bottom of the horizontal section of the drain line after the trap, thread the holes and put two screws into the holes with a little pookie. Wire the two screws up to the metal contacts on the GRI.

Just a brain storm. I don't know if the two metal contacts on the gri are some special alloy or if any metal would do.
 
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