[Hai-users] Omnistats not talking to Aegis any more

[Dudoussat, Scott A.]

Check Output 8 by reading the DC voltage between Output 8 and GND using
a voltmeter.  Can you see a transition between 0 and 12 volts?  If the
meter doesn't show a transition (i.e. steady 0V or 12V), the chip U31
(MIC2981) that drives the outputs is suspect.  Replace U31 and confirm
that the temperature is properly displayed.

You can purchase a replacement MIC2981 for the HAI Web Store at
http://www.easycart.net/HAI/Hardware.html.

-Scott

-----Original Message-----
From: hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com] On
Behalf Of Eric Rosenquist
Sent: Thursday, November 29, 2007 6:09 PM
To: HAI Users Mailing List
Subject: [Hai-users] Omnistats not talking to Aegis any more

As of a few months ago, my 3 Omnistats are no longer talking to my Aegis
(=
Omni Pro) controller.

We had a couple of brownouts a few months ago and I thought maybe a
power
glitch was the reason, but a reset of the Aegis RAM didn't make any
difference, so I took a look at the main thermostat. When I popped the
cover
off I was a little miffed to find that a mouse had chewed some of the
Aegis
communication wires but not the heavier HVAC ones. They were chewed
enough
to expose some of the metal strands and quite possibly cause a short. I
snipped the wires off below the chewed portion and reconnected
everything. I
figured that my problem was solved, but I still can't get the
thermostats to
talk to the Aegis.

Here's what I've tried so far:

* Verified that the wiring to all 3 is good. I even tested the red wire
to
make sure it was properly connected to the black at each thermostat. The
tests tell me that I don't have any breaks in the wiring to the
thermostats
nor any crossed wires.

* Took my thermostats over to a neighbour's house and plugged them in,
replacing one of his Omnistats. Both of the units I took over (the 3rd
was
running the furnace at the time) got the time of day from the Aegis very
quickly and were therefore able to talk to his controller. This tells me
that the problem is not the thermostats.

* Disconnected all 3 thermostats and then connected each of them so that
they were the only one connected and powered up. I waited 10-15 minutes
after connecting each time but it didn't make any difference. I also
tried
connecting one directly to the controller using a new wire, eliminating
the
other t-stats and the existing wiring. No difference.

* Checked that all of the t-stats have unique IDs and are set for
"system"
communication mode. 

* Changed all thermostat types to "not used" and then back to heat/cool
just
to ensure that the Aegis knows I have thermostats and sets zone 16 and
output 8 for thermostat communication.

* Reset the Aegis RAM and then reloaded all of the programming. 

* Disconnected the AC and battery power to the main Aegis board, waited
20
minutes, then reconnected power & battery.

* Changed all thermostat types to "not used" to see if zone 16 and
output 8
were working. With Z16 open I get a reading of about 252. With a
resistor
across it I get 146 or 147. With it shorted I get about 127. The odd
thing
is that I can't get Output 8 to go back to being a regular 12V output.
Even
with the thermostats not configured I always read around 2.6VDC on
output 8
regardless of whether it's ON or OFF. Is there some other setting that
controls the mode of output 8? The other outputs read a little over
12VDC
when ON and next to nothing when OFF as expected.

Suggestions/ideas are welcome!

Eric

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