Official Insteon/Venstar Thermostat How To Thread

hi guys. i am looking to install the the 1900 and have been through this thread and through the manual, i am concerned that my current 4-wire setup is not sufficient and i'm not sure that the add a wire can help.

at the moment the RC and RH contacts are jumpered on my thermostat. i read the other honeywell case and it seemed to be different for him.

anyone have any seminal pointers on what my approach should be here, given that running an additional wire is pretty much out of the question at this point... would involve some impossible fishing across a lower level ceiling, etc.

tia!

[matt (support)]

I think the Add-A-Wire kit will work in this case. Based on the Add-A-Wire Manual it cannot be used on the power (R) or common (C) wires, but it can be used to add any of the control wires (G, Y, and maybe W). There are some good wiring diagrams there that will probably help. You'll be re-wiring it on the thermostat end and the furnace/blower end.

This post might also help describe your current setup. RH/RC are the power leads for heat/cool and are often jumpered together. So looking at the wiring diagram in the PDF above, your RH/RC wire is the same as R (I think).

Regards,
Matt

I just got two Venstar 1900 thermostats from Smarthome. It seems to me that I'm missing mounting brackets for them. There are two rows of very small pin jacks along the back sides, clearly corresponding to the wiring pins they show, but nothing to plug them in to.

Do these come with brackets? If not, where do you get them? I haven't been able to find anything with google.

[matt (support)]

If I recall correctly, my Venstar came in essentially two halves. The back half is mounted into the wall and has screw terminals for the HVAC wires. The front half (with the display) then snaps into the back half. Sounds like you are missing the entire back half?

Do recall whether the front half had a white plastic back, or did the front half have exposed circuitry on its back?

Thanks.

After talking to SmartHome support, I tried harder to get the back off, and this time it worked. Those pins hold the back on very tenaciously.

Can you describe how you got the back off the thermostat T1700 to facilitate mounting/and getting access to the screw connects? There is no on-line/included documentation on this, and I am concerned about damaging the plastic shell trying to open it.

Thanks, Rick

It does seem like it's going to break but it won't. It has pins on both sides in the back, you just need to rock it a bit back and forth and eventually it will come apart.

I finally got working Insteon controllers for my Venstars, and am thinking about how to program them from Indigo. Right now, they're running an internal program that sets the heat back at night. I'd like to turn that program off and use Indigo to change the set points, so than I can, for example, turn the heat down when I go to bed rather than at a particular time. I assume that this will be sufficiently reliable.

The Venstar has a feature where it measures how long it takes to raise the heat to the setpoint, and uses the programmed time as the goal for when the heat should be at that temp, rather than the time at which it should start raising the temp.

It seems that it would be somewhat difficult to emulate that in Indigo, certainly without Applescript.

Has anyone taken a stab at that? I'd love to hear any advice. Meanwhile, I'm just going to set it to change early.

Thanks.

The Venstar has a feature where it measures how long it takes to raise the heat to the setpoint, and uses the programmed time as the goal for when the heat should be at that temp, rather than the time at which it should start raising the temp.

It seems that it would be somewhat difficult to emulate that in Indigo, certainly without Applescript.

Has anyone taken a stab at that? I'd love to hear any advice. Meanwhile, I'm just going to set it to change early.

Thanks.

I don't have a venstar, but the actual logic is fairly straight forward...

You could have a variable defined in Indigo, let's say "minutes_to_raise_1deg".. Which would contain the number of minutes it takes to raise the house 1 deg...

So you could poll the venstar, and find the current temperature...

degrees_to_raise = desired_temperature - current temperature
if degrees_to_raise < 1 fail (house needs to cool, not increase)

time_needed = degrees_to_raise * minutes_to_raise_1deg

so you would need to start time_needed minutes before the reprogramming... So in otherwords, move the event that number of minutes ahead of it's normal schedule...

Can Indigo tell if the thermostat is calling for heat? I would like to turn on a fan when the heat is on.

Thanks,
Kenny

Can Indigo tell if the thermostat is calling for heat? I would like to turn on a fan when the heat is on.

Why not let the thermostat do that itself? Or do you not have forced air?

Perhaps you could tell by noticing that the heat setpoint is above the current temperature.

[matt (support)]

Hi Kenny,

Can Indigo tell if the thermostat is calling for heat? I would like to turn on a fan when the heat is on.

The INSTEON Thermostat Adapter does not report to Indigo any of the current operation states for the heat/compressor/fan. It does report the mode, set points, primary temperature, and humidity (if you have the humidity module). At Stoney mentioned you could try to calculate if the heat is on by comparing the temperature and heat setpoint. That won't be 100% accurate, however.

I'm monitoring my thermostat's output signals by rectifying the AC with a diode, capacitor and a couple of resistors and feeding the DC signals into a EZIO module. It's messy and expensive, but works well.

I'm monitoring my thermostat's output signals by rectifying the AC with a diode, capacitor and a couple of resistors and feeding the DC signals into a EZIO module. It's messy and expensive, but works well.

Otis, would you mind sharing the component values and circuit? Assume you're using the cap for filtering and the resistor(s) for current limiting, correct? Wonder if a bridge rectifier chip would be enough "filtering" w/o the cap...how sensitive is the EZIO to pulse DC at 60 or 120 Hz?