Re: Water heater eating X-10 signal

["Robert Green" <ROBERT_GREEN1963@xxxxxxxxx>]

"Dan Lanciani" <ddl@danlan.*com> wrote in message
news:1338677@xxxxxxxxxxxxxxxxxxxxxx
> In article <E9ydnWRPweMgFqnbnZ2dnUVZ_rWnnZ2d@xxxxxxx>,
ROBERT_GREEN1963@xxxxxxxxx (Robert Green) writes:
>
> | This really is a fascinating problem.  I never expected that you'd get 5
> | bars at the light switch.  I'm thinking that for whatever reason, the
signal
> | reaching the wall switches is corrupted and that the earlier threads
> | regarding interaction between the two phases was correct.
>
> The problems with this are that (1) such interaction should cause simple
> cancellation rather than corruption per se (unless the repeater is doing
> something really strange like sending out of sync--that particular
repeater
> is known to be a bit odd) and (2) with the elements off there would have
> to be a big capacitor leg-to-leg or such and I can't see why that would
> be the case.  The original poster is welcome to try my spare/repaired
> CR230 if he wants to rule out repeater oddness.

I didn't intend for "interaction between the phases" to exclude any funny
business from the Leviton repeater. (-:  It's still a primary culprit and
why I just ordered an XTB II from Jeff.  Even though the XTBs have worked
flawlessly, I really *do* need a repeater for controllers that can't be
routed through an XTB. But I need one that works for my particular usage
pattern and equipment inventory.  That wasn't the Leviton.  I'm hoping it
*will* be the XTB-II.

It was a long time ago, but IIRC, the most irksome issue was the constant
locking up and resetting involved.  The X-10 floodlights seemed to be the
culprit but I never ran it to ground.  Each lockup caused a significant drop
in SAF for X-10, so I went the multiple transceiver route, with its many
perils but fewer trips to the circuit panel overall.  That's very generous
of you to offer your spare for testing.

> | The lack of low voltage feeds to the water heater suggests to me that
> | there's a switching power supply capable of running from 240 volts
inside
> | the unit.
>
> Traditionally 240V appliances use a 240V transformer for the control
> supply (which is usually 24VAC), but then again traditionally water
> heaters don't have low voltage control circuitry at all.  At this
> point popping the cover of the heater seems in order.

I suppose it would end the speculation, at least.  When I was looking for GE
specific water heater schematics I did see some newer (tankless, I believe)
units that had switch mode power supplies.  It's getting harder and harder
to find traditional transformer-based low voltage power supplies.  The
latest batch of cameras I got had tiny 500mA 12VDC SM power supplies that
appeared to be X-10 friendly so I am going to order some more to replace the
large transformer-based 500mA I'm using now.  In any event, powering a
switch mode supply from two hot legs is probably something we've not seen
much of  - yet.  Transformers were the industry standard. I suspect we'll be
seeing a lot more SM power supplies in strange places as the push to reduce
carbon emissions gains momentum.

> | They are a known plague to X-10 and could be the source of the
> | noise that Dan has suggested might be the problem.  If so, it might be
> | possible to filter only the control circuitry inside the unit, but it
> | wouldn't be a very clean fix and it would probably be impossible to get
it
> | inspected with such a jury rigging.
>
> I don't know; I was thinking that that would indeed be the clean fix.
> HVAC folks are always doing quasi-custom hacks to installed equipment
> (some not too neatly) so maybe it isn't a big deal.

After I wrote that and sent it, I realized "impossible" was too strong a
word, even modified by "probably."  The actuality is that if there's enough
room in the control hatch, no inspector would ever be likely to see it.

> | Dan points out that might not be the case as he's seen wall switches
suffer
> | from interference that did not register on the ESM1 so without a scope
or
> | analyzer, it's very hard to say for sure.
>
> And in fact it was pretty hard to see even on a scope.  Those switches
> seem to be among the most sensitive X10 receivers.  Given the strong
> signal at the switch it might be worth testing the noise theory by
> connecting a 0.1uF capacitor across one of the switches.  If that makes
> the problem go away it is likely noise, but you can't really leave the
> capacitor there. :)

If I had spent all weekend trying to get the porchlights back on, I might be
tempted to hardwire it into a box.

> (You can desensitize the switch as I've described  elsewhere, but that's a
last
> resort.)

The more I think about it, the more I think it's noise from a switch mode PS
being fed into the Leviton repeater in a way that the designers never
intended.  It would be *so* nice to see what the Monterey reads at the wall
switch in noise, analysis and signal dissect modes.  Signal dissect would be
able to read the voltage level of each bit and that usually tells you, at
least in collisions, which units are colliding.

At some point we should be able to learn what's inside the GE unit, either
from Mr. Land or some GE instruction manual.  I might even go to Home Depot
to see for myself.  Gotta take my N-vision CFL floodlight back, anyway.  It
began taking longer and longer to warm up and now it never warms up
completely.  Too bad.  It was X-10 AND current sense friendly, too.

--
Bobby G.