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 Want 3-spd Blower on 2441TH & Mitsubishi Heat Pump
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Posted - 02/06/2017 :  6:04:22 PM  Show Profile  Reply with Quote

For anyone who knows HVAC systems, the following boils down to a pretty pedestrian inquiry, but the components themselves may be somewhat unusual so I'll describe them first...pausing only to state that everything is already up and running properly, *except* for the 3-speed blower control I'm currently after.

The Players...

2441TH *Standard* Insteon Thermostat
(yes, STANDARD thermostat, on a heat pump, up and running fine due to next item...)

Mitsubishi PAC-US444CN-1 Thermostat Adapter (current device):
Adapts Heat Pump system to use a STANDARD thermostat instead of MHK-1, warns NOT to use a "heat pump"-type stat with the PAC-US444CN-1.

Mitsubishi MHK-1 Wireless Thermostat with 3-speed blower control (This is a FORMER DEVICE, named here for reference only.) Removed in favor of PAC-US444CN-1 & 2441TH, the MHK-1 is a rebranded Honeywell RedLink item. I had 3-speed blower but no Insteon control, hence the removal. Now I have Insteon but no 3-speed blower.

Mitsubishi PVA-A30AA4 Air Handler with 3-speed blower driving...

Mitsubishi PUZ-HA30NHA4 Heat Pump


For casual readers, the wireless MHK-1 thermostat comes paired with a dedicated receiver that mounts at the furnace or air handler. Connection to that air system is by a single, modular plug that delivers who-knows-what for signaling to the actual heat/cooling package, but that one little plug delivers it all and is not a good access point for tinkering.

A common complaint of the described heat pump system is that little else but an MHK-1 can control it. Did you like your previously-existing thermostat? Forget it, you have to use an MHK-1 or maybe one or two other rebranded "Mitsubishi" stats of the same family and appearance.

After my new heat pump system (with an MHK-1) was installed I soon missed the Insteon control I'd had with my former common gas furnace and, just around then, Mitsubishi introduced their new PAC-US444CN-1 alternative to the MHK-1 and a real game changer in that I can now use virtually any normal, wired thermostat in existence with my new high-tech heat pump, though the new adapter does prefer a stat with two-each Heat and Cool stages if it can get them.

The PAC-US444CN-1 uses the same, single, modular plug as the MHK-1 to connect to the air handler but at the other side of that little box (which is NOT radio-capable), are the following common terminals long-known to HVAC techs:


The Insteon 2441TH stat is connected to the above using all 7 terminals found inside the stat, including a wire to "G" which is the single blower control wire in use. My air system thus runs at full blower speed nearly all the time, only slowing down a little while the system warms up for a call for heat.


I'm thinking that, using the above connections, I can add independent IOLincs and get my 3-speed blower back too and herein I have questions since I don't fully comprehend the four G terminals...

1) If blower is controlled using G1-G2-G3, is the connection at G removed?

2) As a manual, hardwired change (and neglecting my 3-speed goal for the moment)...Could I just move the G wire to G1, G2, or G3 to change to a single, different blower speed?

3) If G1, G2, & G3 are all wired, must only ONE terminal be active at any given moment, or will they tolerate a momentary "ON" signal at more than one of the terminals, in case the IOLincs briefly "overlapped" each other through slow or missed Insteon "ON" or "OFF" signals for example?

Thanks for any wisdom, I don't want to bungle the setup of those G-terminals on my pricey new HVAC system.

- Snibley

- Snibley


15850 Posts

Posted - 02/06/2017 :  10:19:37 PM  Show Profile  Visit stusviews's Homepage  Reply with Quote
You would not use the G terminal on the Insteon thermostat at all. Instead you would connect I/O Lincs to switch between G1, G2 and G3. C connects to the COM terminal on each I/O Linc. But there's more:

You need to ensure that one and only one of the I/O Lincs is always on when either heating or cooling is called for. Instantaneous response is not required. In fact, if there's no blower, the HVAC will still function, but it won't blow air through the vents.

What are you using as an Insteon manager, a Hub, software, an ISY, something else.

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Starting Member

7 Posts

Posted - 02/06/2017 :  10:52:31 PM  Show Profile  Reply with Quote
Hello Stusviews,

>You would not use the G terminal on the Insteon thermostat at all. Instead you would connect I/O Lincs to switch between G1, G2 and G3. C connects to the COM terminal on each I/O Linc.<

All clear, that's 3 IOLincs.

>Instantaneous response is not required. In fact, if there's no blower...<

OK, it's clear that...
a) Exactly one IOL *should* be on at any moment;
b) If all 3 IOL's happen to be off, no damage...just no air.

...But what if 2 or 3 ended up being simultaneously ON? Any damage likely?


ISY994iZw IR Pro: I have much to grow into. You, LeeG, Teken etc., have taught me a lot, sir.

Thanks for the needed insight & will watch for more.

- Snibley
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5676 Posts

Posted - 02/07/2017 :  03:14:48 AM  Show Profile  Reply with Quote
The Smartenit EZI04 has four relays in it. That module may also work for you.

I see on their web site it has been replaced by their IoT4R module. That added Internet of Things feature along with X10 and Insteon support.
I am not sure if that would cause ISY994i issues. You could ask in the UDI Forums.
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7 Posts

Posted - 02/07/2017 :  10:48:59 AM  Show Profile  Reply with Quote


It took me a year to ask re 3-speed blower but now I'm getting stoked:

The IoT4R does look good. Nothing definitive on UDI forum yet re ISY integration but I might take a chance on it anyway.

I'm just now realizing the entire scheme can be implemented at the air handler, meaning the 4th relay could then control the site's powered fresh air damper which currently is controlled by an ON-OFF module.

Thanks again for the nudge re IoT4R; in the past I'd bought their EZRains but had kind of written off that source since my battles with the EZSrve / early Harmony products.

Good idea BLH, thanks again.

- Snibley
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Starting Member

7 Posts

Posted - 02/13/2017 :  2:24:38 PM  Show Profile  Reply with Quote
Follow-up / General FYI for others considering purchase:

Per BLH's suggestion I ordered an IoT4R (model 5010V) direct from Smartenit website and received it today, 13 Feb 2017.

Unit linked successfully by ISY994iZw IR Pro on 4.5.4 firmware using "Start Linking" under "Link Management".

I haven't programmed for the device yet but did test all 4 relays which responded with the expected contact clicks.

Hardware received has label reading "2233-233" ; "V2.2" ; "1545".

ISY recognizes unit as: "Compacta EZIO4O v.05"

I'm now positive the device will work for my application, thanks again BLH and stusviews.

- Snibley
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5676 Posts

Posted - 02/13/2017 :  3:11:26 PM  Show Profile  Reply with Quote
Thanks for the follow-up.
Compacta was the original name of the company.
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