Elk and multi-zone HVAC system...

[SBoyd]

Hi All,

I am torn between an M1 and an Omni II, and while I am leaning heavily towards the M1 at this point, a very immediate issue here may be the determining point.

From what I understand, the M1 only has 4 thermostat "ids" for use, whereas the Omini supports 16. I am considering biting the bullet on an underfloor radiant heat retrofit in the next week or so and have to determine the number of zones. It is for a weekend house in the country, and we have no need to heat guest rooms that are not in use, so I would like to have more than the 4 zones that the current system has. If I go with the M1, how will I do that? I have read the posts about using the TS40s with the RCS zone controllers, but to be honest, I like the aesthetic (and price) of the HAI thermos, and I understand (from the board) that they will work fine.

So, can I use more than 4 HAI thermos with the M1?

Thanks for your input...

 

[rfdesq]

So, can I use more than 4 HAI thermos with the M1?

From the M1XSP manual:

"The max. number of HAI Tstats that may be connected to a single M1XSP is four (4). Max. wire distance = 500 ft. Each Tstat must be assigned a unique address from 1 to 4. IMPORTANT: HAI Tstat addresses 1 to 4 MUST be connected to an M1XSP that is set to data bus address 1. HAI Tstat addresses 5 to 8 MUST be connected to an M1XSP that is set to data bus address 2. HAI Tstat addresses 9 to 12 MUST be connected to an M1XSP that is set to data bus address 3. HAI Tstat addresses 13 to 16 MUST be connected to an M1XSP that is set to data bus address 4."

 

[SBoyd]

Excellent news, thank you! So by adding another MX1SP I can add a few more thermos, and thereby a few more heating zones...

Any downsides to using the HAI thermos over the RCS or Aprilaire? The new blue goes nicely with the raft of Insteon switches I have put in, and should pair nicely with the Elk KP2, no?

 

[Mike]

My only complaint with the HAI thermostats is that they sometimes don't 'snap' into their base quite right. Not a huge deal (and you can usually play with it to get it right) and when it came to buying more I chose to get another versus starting over with another brand (the others are a lot more expensive).

The other consideration was that when it is automated, you rarely use the thermostat other than to look at the temperature. The blue is nice. Just make sure it is mounted at the right level (too much of an angle when viewing and it does not look right, although that is a pretty big angle).

 

[rfdesq]

Any downsides to using the HAI thermos over the RCS or Aprilaire? The new blue goes nicely with the raft of Insteon switches I have put in, and should pair nicely with the Elk KP2, no?

Sorry, I still haven't chosen the TStat's that I'm going to use. I'll let those with experience answer and I'll sit back and learn.

 

[SBoyd]

Thanks for the advice Mike. I'll give HAI a call to see which of their 'stats would work best with my system.

Silly question, but obviously the M1 can poll the thermo for temperature (otherwise it would be very useful, would it), but can that then be displayed on the keypads or other screens? Bearing in mind that I will need a couple of M1XSP's and will probably have 5 or 6 thermostats/zones, as each 'stat has an independent address, that would mean the M1 would understand each one as a separate zone, right? It would not consider the M1XSP to be a single zone and the 'stats on that to just be additional inputs???

 

[Mike]

I believe you can put the thermostat information on the keypad, but I have not done it. Not sure of multiple stats either.

Another comment on thermostats, I believe there was a quote about getting the message functionality to work on the aprilaire stats. Meaning put messages on the thermostat from the elk. This was kind of neat, but I don't remember if I saw that posted as actually working yet. It is a bit more money (which is why I did not scrap my current HAI one when getting another one), if I was starting from scratch, and if that worked I might give it more thought.

Again, however, it would depend on how often you plan on looking at the thing...

 

[Spanky]

Clarification:
HAI Thermostats are limited to 4 per M1XSP serial port expander because of the pseudo RS232 drivers on the HAI Thermostats. There is a 16 Thermostat maximum on the M1, 4 per M1XSP.

RCS and Aprilaire can have 16 Thermostats on one M1XSP because they use RS485 drivers.