Water heater eating X-10 signal

Hello,

I've had a modest X-10 system running in our house for a few years.
It took me a while to get it working reliably enough to get the WAF to
a level where my wife wasn't cursing "HAL" every other day.

Part of that effort involved installing an active phase coupler in our
mains panel. Everything was working pretty well, until we recently
added an electric water heater to the panel.

The water heater is wired to a double pole 30 amp breaker in the panel
via about 60' of 10/2 w/ground (no neutral connection on the heater,
just the two hots). After I installed it I noticed that our X-10
controlled outside lights weren't coming on in the evenings. After a
little troubleshooting I discovered that if I switched off the breaker
for the heater, the X-10 system went back to normal. Switching the
breaker on makes the problem reappear.

I'm guessing that the connection to heater and/or the heater itself is
"sinking" the X-10 signal.

Is there a wired, in-line filter available that I can fit in after the
breaker to block the X-10 signal from the heater and its wiring? Is
that the correct approach in this case?

Thanks.

I don't believe there is any commercially available filter that can handle
30 amps. The largest is the big XPF, which is rated for 20 amps. It would
take 4 of them to filter both hot leads running to the water heater.

A heavy electrical load across the two phases normally helps X10 signal
distribution, so there must be something more here than just the heater
element. There may be some sort of surge protection shunting the X10 signal
to ground. Perhaps your signals were marginal before adding the heater.

It might be a good idea to invest in a X10 signal level meter, such as the
ESM1, to find out what is really going on. Since filtering a high current
load is not very practical, the only suggestion I have if it is the water
heater is to increase your signal strength beyond what your active phase
coupler can do.

Jeff

<graftonfot@yahoo.com> wrote in message
news:1176757871.575204.16020@n76g2000hsh.googlegro ups.com...
> Hello,
>
> I've had a modest X-10 system running in our house for a few years.
> It took me a while to get it working reliably enough to get the WAF to
> a level where my wife wasn't cursing "HAL" every other day.
>
> Part of that effort involved installing an active phase coupler in our
> mains panel. Everything was working pretty well, until we recently
> added an electric water heater to the panel.
>
> The water heater is wired to a double pole 30 amp breaker in the panel
> via about 60' of 10/2 w/ground (no neutral connection on the heater,
> just the two hots). After I installed it I noticed that our X-10
> controlled outside lights weren't coming on in the evenings. After a
> little troubleshooting I discovered that if I switched off the breaker
> for the heater, the X-10 system went back to normal. Switching the
> breaker on makes the problem reappear.
>
> I'm guessing that the connection to heater and/or the heater itself is
> "sinking" the X-10 signal.
>
> Is there a wired, in-line filter available that I can fit in after the
> breaker to block the X-10 signal from the heater and its wiring? Is
> that the correct approach in this case?
>
> Thanks.

graftonfot@yahoo.com wrote:

>Hello,
>
>I've had a modest X-10 system running in our house for a few years.
>It took me a while to get it working reliably enough to get the WAF to
>a level where my wife wasn't cursing "HAL" every other day.
>
>Part of that effort involved installing an active phase coupler in our
>mains panel. Everything was working pretty well, until we recently
>added an electric water heater to the panel.
>
>The water heater is wired to a double pole 30 amp breaker in the panel
>via about 60' of 10/2 w/ground (no neutral connection on the heater,
>just the two hots). After I installed it I noticed that our X-10
>controlled outside lights weren't coming on in the evenings. After a
>little troubleshooting I discovered that if I switched off the breaker
>for the heater, the X-10 system went back to normal. Switching the
>breaker on makes the problem reappear.
>
>I'm guessing that the connection to heater and/or the heater itself is
>"sinking" the X-10 signal.
>
>Is there a wired, in-line filter available that I can fit in after the
>breaker to block the X-10 signal from the heater and its wiring? Is
>that the correct approach in this case?
>
>Thanks.

What happens if you disable your active coupler?

http://davehouston.net
http://tech.groups.yahoo.com/group/roZetta/
roZetta-subscribe@yahoogroups.com

In article <tqSUh.312813$5j1.241452@bgtnsc04-news.ops.worldnet.att.net>, JeffVolp@msn.com (Jeff Volp) writes:

| A heavy electrical load across the two phases normally helps X10 signal
| distribution, so there must be something more here than just the heater
| element.

He mentioned that he has an "active phase coupler." If by that he
means what we normally call a repeater and if the repeater is of a
design that drives the two legs out of phase then a heavy leg-to-leg
load will diminish the apparent signal level as the carriers interfere
destructively.

Dan Lanciani
ddl@danlan.*com

"Dan Lanciani" <ddl@danlan.*com> wrote in message
news:1338633@news1.IPSWITCHS.CMM...
> In article <tqSUh.312813$5j1.241452@bgtnsc04-news.ops.worldnet.att.net>,
> JeffVolp@msn.com (Jeff Volp) writes:
>
> | A heavy electrical load across the two phases normally helps X10 signal
> | distribution, so there must be something more here than just the heater
> | element.
>
> He mentioned that he has an "active phase coupler." If by that he
> means what we normally call a repeater and if the repeater is of a
> design that drives the two legs out of phase then a heavy leg-to-leg
> load will diminish the apparent signal level as the carriers interfere
> destructively.

Hi Dan,

I had thought of that, but I didn't think any repeater would drive the two
legs out of phase due to that exact issue. Any 240V resistive load, such as
a dryer or stove, would squash the signal. But it is possible...

Jeff

In article <5YVUh.313769$5j1.279572@bgtnsc04-news.ops.worldnet.att.net>, JeffVolp@msn.com (Jeff Volp) writes:
| "Dan Lanciani" <ddl@danlan.*com> wrote in message
| news:1338633@news1.IPSWITCHS.CMM...
| > In article <tqSUh.312813$5j1.241452@bgtnsc04-news.ops.worldnet.att.net>,
| > JeffVolp@msn.com (Jeff Volp) writes:
| >
| > | A heavy electrical load across the two phases normally helps X10 signal
| > | distribution, so there must be something more here than just the heater
| > | element.
| >
| > He mentioned that he has an "active phase coupler." If by that he
| > means what we normally call a repeater and if the repeater is of a
| > design that drives the two legs out of phase then a heavy leg-to-leg
| > load will diminish the apparent signal level as the carriers interfere
| > destructively.
|
| Hi Dan,
|
| I had thought of that, but I didn't think any repeater would drive the two
| legs out of phase due to that exact issue. Any 240V resistive load, such as
| a dryer or stove, would squash the signal. But it is possible...

The only repeater whose circuit I've traced (ACT CR230) drives them out
of phase. My understanding has always been that this is the standard
practice in order to accommodate 240V modules which would otherwise have
a difficult time seeing the signal. I assume it is also the reason for
the standard warning about using a repeater in conjunction with the
blocker/coupler. Have you ever encountered a repeater that drives the
legs in phase (ignoring your own designs, of course ? I have the
original Leviton unit (i.e., the one before the one before the current
one) but I'm not sure it's worth the bother to take it apart and trace
the circuit.

Dan Lanciani
ddl@danlan.*com

"Dan Lanciani" <ddl@danlan.*com> wrote in message
news:1338634@news1.IPSWITCHS.CMM...
>
> The only repeater whose circuit I've traced (ACT CR230) drives them out
> of phase. My understanding has always been that this is the standard
> practice in order to accommodate 240V modules which would otherwise have
> a difficult time seeing the signal. I assume it is also the reason for
> the standard warning about using a repeater in conjunction with the
> blocker/coupler. Have you ever encountered a repeater that drives the
> legs in phase (ignoring your own designs, of course ? I have the
> original Leviton unit (i.e., the one before the one before the current
> one) but I'm not sure it's worth the bother to take it apart and trace
> the circuit.

That's an interesting thought regarding 240V modules. Of course, the
percentage of those is miniscule compared with 120V modules used on
split-phase systems.

Since most X10 modules work fine down to 100 mV, or even lower, it would
take almost perfectly balanced attenuation in both legs for in-phase signals
to null enough at the 240V device to cause a problem. With the small
percentage of 240V devices in service, it would seem to make more sense to
use in-phase drive so 240V resistive loads would not attenuate the signal.
You are correct in your assumption that the XTB-II drives 120KHz in-phase to
both legs. When I tested the XTB-II here, I measured 30Vpp on one leg, and
25Vpp on the other leg due to an imbalance in loading. So, a 240V circuit
would start off with a 5Vpp differential signal at the panel.

The commonly used .1uF passive coupler will drive both legs in-phase, but
the second leg will always be lower in amplitude. That again would provide
sufficient signal to a 240V module bridged across both legs.

I have a couple of the old Leviton 6201s kicking around. If I get a chance,
I'll scope it to see what it does.

Jeff

In article <04YUh.314346$5j1.274986@bgtnsc04-news.ops.worldnet.att.net>, JeffVolp@msn.com (Jeff Volp) writes:

| That's an interesting thought regarding 240V modules.

Incidentally, it isn't my thought; I'm sure I read it somewhere though
I can't remember where. So I wasn't surprised when I saw how the
CR230 was built.

| Of course, the
| percentage of those is miniscule compared with 120V modules used on
| split-phase systems.

The percentage of 240V modules in my home is exactly 0; hence my
interest in a repeater that drives the legs in phase for less
contention with the blocker/coupler.

| Since most X10 modules work fine down to 100 mV, or even lower, it would
| take almost perfectly balanced attenuation in both legs for in-phase signals
| to null enough at the 240V device to cause a problem.

I'm not sure it's that simple. The imbalance required depends on the
strength of the signal at the receiver. If it is already near the sensitivity
threshold then a 50% imbalance could still be insufficient to avoid trouble.
This is basically the generic carrier interference argument where if the
signals are strong enough to begin with then even their difference is likely
sufficient to operate a module. It's why you typically don't see a carrier
interference problem with multiple synchronized transmitters collocated at a
receiver. For a simple protocol, X10 can lead to some pretty complicated
analysis...

| With the small
| percentage of 240V devices in service, it would seem to make more sense to
| use in-phase drive so 240V resistive loads would not attenuate the signal.

I certainly can't see any downside, but then I don't have any 240V receivers.
Possibly the repeater designers know something we don't. I suppose if I
were building a repeater product I'd be tempted to make it a switchable option.
There's something unaesthetic about driving what amounts to a differential
line pair in phase and hoping for random impairments to make it work.

| You are correct in your assumption that the XTB-II drives 120KHz in-phase to
| both legs.

Not an assumption; I asked you before.

| The commonly used .1uF passive coupler will drive both legs in-phase, but
| the second leg will always be lower in amplitude. That again would provide
| sufficient signal to a 240V module bridged across both legs.

It depends. What if the sensitivity of the 240V module is 100mV, it is
currently seeing 100mV on one leg and 0V on the other, and the passive
coupler causes 50mV to appear on the previously-0V leg?

I keep meaning to check whether the official passive coupler flips the
phase. It uses transformers on both sides so it certainly could. My
brief experience with it was quite negative with previously working
transmitter/receiver pairs failing once the coupler was switched in.
Something funny was going on and since there was already significant
passive coupling I wonder if it was somehow producing cancellation.
Of course, this was at a time when I was lucky to have 50mV levels
at some locations.

I'm pretty sure that the blocker/coupler cannot flip the phase because
of the way it blocks, and it was with that device that they started
warning about combination with a repeater.

| I have a couple of the old Leviton 6201s kicking around. If I get a chance,
| I'll scope it to see what it does.

I have the original (two black wires and one white; does not support
extended codes). There was a second rev that supported extended codes
and could drive a third phase but had an absurd power-on sequence
requirement. They were both the same part number, right?

Dan Lanciani
ddl@danlan.*com

"Dan Lanciani" <ddl@danlan.*com> wrote in message
news:1338636@news1.IPSWITCHS.CMM...
> In article <04YUh.314346$5j1.274986@bgtnsc04-news.ops.worldnet.att.net>,
> JeffVolp@msn.com (Jeff Volp) writes:
>
> | That's an interesting thought regarding 240V modules.
>
> Incidentally, it isn't my thought; I'm sure I read it somewhere though
> I can't remember where. So I wasn't surprised when I saw how the
> CR230 was built.
>
> | Of course, the
> | percentage of those is miniscule compared with 120V modules used on
> | split-phase systems.
>
> The percentage of 240V modules in my home is exactly 0; hence my
> interest in a repeater that drives the legs in phase for less
> contention with the blocker/coupler.
>
> | Since most X10 modules work fine down to 100 mV, or even lower, it would
> | take almost perfectly balanced attenuation in both legs for in-phase
> signals
> | to null enough at the 240V device to cause a problem.
>

I am having a hard time with the phrase "in phase" here. Why the worry over
"the phase of the signal" between different legs of the circuit? I get the
feeling you both think the reason that neutral is at 0 volts potential is
that, the voltage waveforms on each leg destructively interfere with each
other due to phase cancellation and not simply as a consequence of vector
addition. I mean that's fine but its hardly the standard model for analysis
of a split-phase power circuit. I suppose you could look at that way but
this has nothing to do with the X10 signal.

As to 240V modules, I'd be surprized if they just didn't listen on one leg
only, since there is no return path for the signal, if one listened only
between legs as that is isolated from neutral--the designated return path of
the source which IS on one leg.

Slammer

In article <oK6dnWuv0qmOMLjbnZ2dnUVZ_jadnZ2d@giganews.com>, mjinks@bellsouth.net (Slammer) writes:

| I am having a hard time with the phrase "in phase" here. Why the worry over
| "the phase of the signal" between different legs of the circuit?

It's germane to the question that started this thread, i.e., why would
adding a leg-to-leg load to an otherwise working system that uses a
repeater induce failure?

| I get the
| feeling you both think the reason that neutral is at 0 volts potential is
| that, the voltage waveforms on each leg destructively interfere with each
| other due to phase cancellation and not simply as a consequence of vector
| addition.

The neutral is often defined as being at 0V potential by convention (and,
pragmatically, because it is usually bonded to a grounding system). It
really has nothing to do with interference or the vector addition that
can represent same. In reality, only potential _differences_ are meaningful
and you could just as well choose something other than the neutral as your
0V reference if it makes the analysis easier. Many X10 modules use a hot
leg (rather than neutral) as their logic 0V reference. It is convenient to
adopt that convention when working on such circuits since otherwise you
have to deal with Vcc being a 5V DC signal added to the 120V line supply
with respect to neutral.

| As to 240V modules, I'd be surprized if they just didn't listen on one leg
| only,

How exactly would you propose that a 240V module listen on one leg only?
Remember, you can't measure potentials; you can measure only potential
_differences_.

Dan Lanciani
ddl@danlan.*com