Relay based on Insteon Micro On/Off module

[etsvilik]

I have an existing thermostat for radiant heat floors which has control contacts to activate Vacation mode.  I wished to have it controlled form ISY when we are away or on Vacation. I didn't want to invest into wi-fi smart thermostats. There are very few existing that have external  in-floor temperature floor sensor connectivity.

 

I was looking for small remote controllable relay with NO contacts that I can activate via Insteon. It had to be small enough to fit behind one-gang box behind the thermostat. I could not find any. I/O link is huge and Insteon micro on/off modules 2443 switches line voltage. 

 

I went ahead and modified micro on/off module to convert to NO relay.  I utilized extra, unused  wire terminal on the module to use it as another leg for the relay. It is not marked on the module case and internally jumped to a Load L1 terminal. Now I have Load and this 2nd terminal used in Normally open relay contact. Line voltage only is used to power the module and pass Insteon signal. Module is Dual Band so it uses RF as well.  I wish  SmartHome would just offer such module as I'm in need of few of those devices

(Doing Pool Heater remote  control next)

 

I do not recommend doing it if you are not comfortable with electricity, soldering and working with PC boards. Obviously this is dangerous to modify and use modified electric device so be forewarned.

 

1. Open the case using small flat screwdriver , pushing on 4 tabs.
2. Carefully pull the PC board out of the case. RF module with contact plug will be left on the case.
3. Using soldering iron and week or pump clear few points on the border. Cut traces and solder jumpers per attached photos. The goal is to separate two center terminals from each other and Line voltage. 
4. Carefully inspect and check with Ohmmeter to insure there is no shorts on PCB. Blow and clean the PCB from any metal particles left.

[io_guy]

Hopefully it doesn't overheat and set your house on fire, you're mod completely voided and UL rating of the unit.

[stusviews]

Nice job. Did you modify the device because you're switching low voltage (i.e., 24VAC)?

[larryllix]

I thought about the same thing with an On/Off plug-in module instead of a single-band IO/Link that has such a limited output and input voltage range.

[etsvilik]

Yes, It is low voltage control contacts. No load, just short the input terminals designated for Vacation mode on the thermostat. 

@io-guy. Of course I realize the mod is not kosher. However i'm pretty comfortable with electronics and check the relay specs, etc before doing it. The relay this module uses is 16 Amp High capacity, 250VAC max switching, insulated for high temperatures operation. My thermostat is running cold.  I don't see how my change of  contacts remapping  can overheat this mechanical relay.

[Brian H]

Nice modification. Thank you for sharing.

[pyrorobert]

I'm just curious, instead of modifying the Micro module, why not add an isolation Relay that would be controlled by the Micro module. It would be safer as they are meant to handle any load depending on the rating of the relay, plus you have Form C contacts on them.

 

 

 

Robert