X10 switch control logic

I have a 3 way hard wired switch for a whole house fan that I want to replace with non dimming X10 switches. (I do know and accept the X10 reliability factors)

The existing switch has 3 positions HI SPEED | OFF | LOW SPEED. It is wired 1 wire to power (high) 1 wire to motor Low, 1 wire to motor Hi. The motor has 3 wires; Hi speed, Low speed Neutral.

I am thinking I can replace this with 2 separate non dimming X10 switches. The 1st would be a ON | OFF toggle style switch, that would connect the power (hi) to the common contact of the second switch, a non dimming 2 way ON | ON toggle style switch. One of the 2 switched contacts to be connected to the motor Hi, and the other switched contact to be connected to motor Low.

I would mount both switches side by side with the ON | OFF switch to the left and the HI | LOW to the right for best natural action. One of my major complaints with the existing switch is that the center OFF is easy to miss if you are in a hurry, and strangers will almost always use the WRONG position for the HI / LOW speed. If I mount the switch upside down we all seem to pick the WRONG one. Using a separate switch (UP for HI | DOWN for LOW) makes sense from the way that other switches generally work.

Eventually I intend to use a computer and utilize the X10 control features to turn a fan on conditionally when the inside temperature exceeds the outside temperature and the inside temperature exceeds a predetermined TARGET-TEMP value. The fan would always turn on to the LOW speed condition, but then if the outside temperature exceeds a predetermined USE_MAX_FAN parameter after 30 seconds the second switch would be set to the HIGH speed position. In all cases the turn off command would reset the speed to LOW.

The fan manufacturer specifies that the fan be started at low speed, but the supplied switch doesn't force that, and you can see considerable arcing in the switch if you start it in the high speed position (easy to do this).

Reply to
J Baber
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Jim Replies: I suspect you might be correct, but as I replied to others, a whole house fan is larger that typical ceiling fans and the one I have should always be started at the low speed and then switched to the high speed setting (if you want the high speed).

If I were to change to the UPB, Wouldn't I have to change all of the other X10 stuff I have over? I do not have a lot, but enough that I would have to buy 20-30 general controls / switches and 2 thermostats (and I don't recall having seen UPB thermostats)

Jim Baber Email snipped-for-privacy@NOJUNKbaber.org

1350 W Mesa Ave. Fresno CA, 93711 (559) 435-9068 (559) 905-2204 (A no charge Verizon IN cellphone to other Verizon IN accounts) See our 10kW grid tied solar system at "
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Reply to
J Baber

I recommend you look at UPB instead of x10. They work very similar to X10, with one major exception, they actually work.

That said I don't know if wiring x10 switches like that is ok or not.



(easy to

Reply to

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A couple of caveats:

1) beware the _load_ rating on X-10 switch modules. Particluarly with motors. Make sure you're using something rated for the _horsepower_ load of the motor, not just the "watts". "Appliance module" type devices may be indicated. Don't think those exist in a '3-way' (SPDT -- aka your 'on/on' switch) device.

2) If you gang up two switches 'in series', like you're talking about doing, when the 1st switch is 'off', you cannot send commands to the 2nd switch.

I'd be *really* tempted to replace the existing set-up with a couple of relays _at_the_fan_, and run a low-voltage control system.

Both relays are DPDT, with one 'pole' on each relay used for switching the power to the fan -- in the same manner as you envision. On the first relay this pole is the 'on/off' control (SPST-NO), it simply feeds a pole on the second relay which is High/Low (SPDT -- with the NC contact being used for the 'low' speed).

The coil for the 1st relay is controlled simply by the 'on/off' switch.

The second high/low relay has some "slightly" fancy wiring for it.

That wiring goes through the NO contacts on the 2nd pole of the 1st relay, through a NC push-button, and then to (in parallel) a NO push button, and the NO contacts of the 2nd relay. The NC push-button is labelled "low speed", and the NO push-button is labelled "high speed".

In the default (power-up) situation, the 2nd relay is in the 'low speed' setting. *ALWAYS*. because the contacts on the 1st relay were open. when the 1st relay goes power on, the 2nd relay does -not- energise, because the circuit is through the NO contacts on the 2nd relay. When you push the 'high speed' button, the relay pulls in, and those contacts in parallel with the 'high speed' switch close, *keeping* the relay in the 'high speed' setting until power to the coil is interrupted. which happens when *either* the "low speed" button is pushed, _or_ the

1st relay is turned 'off'.

Obviously, you can use 2 push-buttons to control the 1st relay, instead of a 'switch', if you so choose. By simply using another instance of that 'latching' circuit.

For your 'full computer-controlled' automation down the road, some simple transistor 'switches', wired 'alongside' (or instead of) the push-buttons can be controlled from the parallel port.

Reply to
Robert Bonomi

Jim's answer: Point well taken, I just got 1 of the 23893W 2 way togglelinc switches from Smarthome and there is no reference to horsepower in it's documentation. It is rated for a 600 W load, and that is very close to my Hi speed max. startup needs. This switch was kind of strange to me, and is not what I had hoped, and won't work as a single pole double throw switch as I needed for the second switch, although it would serve as the ON | OFF switch. It appears I will eventually need to use X10 selected relays to control the speed selection since I have not found a X10 single pole double pole switch or relay yet, but I am looking.

Jim's answer: I didn't want to do this, the 1st was simply an ON | OFF control the second would be used to select speed. IF I CAN find a single pole DOUBLE THROW switch.

May have to, but now that requires some kind of safety circuit to prevent both the hi and low speed relays being turned on at the same time (you do know X10 hazards)

I haven't fully understood your circuit yet but I am looking at it, Could you Email or reply with a source of the DPDT relay you are describing. It seems to me I could just drive that 1 relay from a second ON | OFF switch to do what I want by wiring the fans Lo speed to a NC relays contact, the fans High speed to the relays NO contact, and the AC LOAD from the 2nd switch to the relays Common. If this as a

110VAC relay it's would have it's coil connected to the AC LOAD from the 1st switch and to AC NEUTRAL, if it is a low voltage relay the coil would be driven from an appropriate power supply for the relay that is controlled by the same AC LOAD from switch 1.
Reply to
J Baber

Jims correction: The coil of the relay would be controlled by the 2nd switch NOT the

1st (SORRY)
Reply to
J Baber

Are you *sure* you don't? :)

What if: (a) the fan is _running_ at high speed, (b) somebody *manually* switches the 'on/off' control to off.

HOW do you _remotely_ "start" at =low= speed the next time?

Nah. The circuit I describe provides that interlocking, *and* automatic 'fall-back' to the low-speed setting in the event of _any_ power-off event. Manual, 'directed', *or* 'un-commanded' (e.g., utility outage).

See the 'schematic' below.

It's just a "standard" DPDT relay, Available from pretty much _any_ electronics supply. Radio Shack sells a relatively inexpensive 4PDT that would do the job. (anything DT with 'at least 2' poles will work, )

The 'magic' is in wiring things up in a 'latching' circuit.

Here's the basic circuit: (the "X" means 'not connected to anything)

O-X O-------------- Fan low AC HOT -------------O---- /---------------O---- . O-----/ . O-------------- Fan high . . . . . +----------------------+ | . O-X | | . o-X |

12V ---o|o-----+----O---- /----o|o----+---O---- | === | . O-----/ === . O----+ | (push off) | . (push for low) . | | +----------------------------+ . | | . | | . | | | . === | . | === | +-------------o o-----+ +------+---o o---+ c (push on) c (push for high) o o i i l l +------+ +------+ | | | | Gnd--------------------------+--------------------------+

Hint: it is actually possible to _combine" the "push on", pushbutton with the "push for low" button, (just requires a SPDT-NO pushbutton, with t all to the 'left' of the 1st relay contact, above) , and then you can make a simple three-button switchplate.


ON / Low


Note: if the fan is OFF, pushing the 'high' button does *nothing*, you have to push the 'ON / low' button to start it.

Reply to
Robert Bonomi

Robert B>Are you *sure* you don't? :)

Jim's answer:

Thanks, You have given me good ideas, I just do not want push buttons because they would be "Non-standard" as far as this house is wired now. Pretty much the same reason that I don't like Decora style switches.

It seems to me I could just drive 1 relay from the second ON | OFF switch to do what I want by wiring the fans Lo speed to a NC relays contact, the fans High speed to the relays NO contact, and the AC LOAD from the 2nd switch to the relays Common. If this as a 110VAC relay it's would have it's coil connected to the AC LOAD from the 1st switch and to AC NEUTRAL, if it is a low voltage relay the coil would be driven from an appropriate power supply for the relay that is controlled by the same AC LOAD from switch 1.

Both switches are SPST

SW 1 ON | OFF O---+---------- Fan low NC contact AC HOT -------------O---- +----------------O---- | O-----+ . O-----+-------- Fan high NO contact . | | . | | NO and NC to 2nd switch . O---+ | with intermittant during ----O----------------------O---- | off (switching) time to SW 2 O . O-----+ cause coil drop out HI on +--------------------------+ c 120 vac coil o /or low voltage power supply i for a SPDT low voltage relay l + | Gnd-/------------------------------------------+------------------ Fan Neutral

Reply to
J Baber

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