Homeseer\Ecobee\Heatpump with oil heat

[Atticka]

So update, much research has been done...

The VStat plugin pretty much connected the dot's on this project and will act as the new zone thermostats for the oil system. I will use the Ecobee room sensors for zone temp input and the PI relay control plugin to operate the zone valves. I will leave the Heatpump operation to the Ecobee3 but use Homeseer to determine when to cut over to oil heating based on outdoor temps.

Thanks for the input!

[Atticka]

Hello,

Diving head first into home automation and this is my first post here!

So far I have a RaspberryPI running Homeseer with a few Insteon light switches and it's running great! Ultimate plan is to expand the Insteon coverage (pretty straightforward process) and automate the HVAC, I think I have this figured out but need some guidance and maybe a second opinion.

Home AC and heating setup
The house has two independent systems; a newer heat pump which offers AC and heating (single zone forced air system, with aux-heat) and an older oil fired hydronic system (forced hot water baseboard radiators) with five heating zones.

Automating the heat pump is relatively straightforward, an Ecobee here and we're done. But the challenge comes when trying to integrate the oil fired system to take over heating duties when the temp hits -8C (in Canada BTW). The oil system still uses the old mercury switches and only two of the five zones actually work (that's a whole other project).

Here is the heating logic I'm trying to accomplish:
Stage1 - Heat pump only down to 0C
Stage2 - Heat pump plus aux-heat down to -8C
Stage3 - Oil furnace only from -8C and below

This is the setup I had in mind:
Outdoor temp sensor
Ecobee thermostat for the Heat pump to control stage1 and stage2 (and ultimately AC in the summer)
Ecobee sensors in each oil heating zone
RaspberryPI with a 8x relay board to control furnace on/off, circulating pump and zone valves

The relay board will be used to control when the oil furnace kicks on (I will not actually mess with the boiler logic, this has its own control system...just a simple on/off when the outside temp hits -8C), when to open the zone control valves and when to turn on the circulating pump (single pump for the house that currently does not seem to operate on when it should). My assumption is that Homeseer can coordinate the logic between the Ecobee and oil furnace components using RaspberryIO and Ecobee plugins (Hi Spud! go habs go!). From what I can tell the oil system is all simple on/off circuits that should be easy to control.

I'm looking for confirmation this will actually work, or any pitfalls I should look out for. This is what I'm a little fuzzy on...
- Can Homeseer handle this logic? I'm fairly new to the platform and still learning its capability.
- Can I use the Ecobee to set\change temp when using the oil heating? In other words Can I tell the Ecobee to halt HVAC heating at a set outdoor temp, but still use the its interface to set temp for the oil heat?
- Is it possible to control when the aux-heat fires?
- Any special considerations when controlling oil heating in Homeseer? It seems almost too simple: if temp in zoneX (ecbobee temp sensor) is below Y(ecobee set temp) then turn on valveX and circulating pump
- Am I over complicating this, or is there an easier way?
- What am I missing? There seems to be some voodoo in dealing with HVAC systems and a knowledge not readily found online

I'm excited at the prospect of automating this! For years we've been manually switching between the two systems.

Thank you for any input!