Replacing Coleman Mach thermostat with Ecobee Si Smart

John Hilley said:

But it was one to one using Duner's chart?

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Not sure but I think so John, I left my documentation in the coach and I'm too pooped to walk back there and get same.  When the dust settles, I'll write this up with a wiring chart and options I chose.

Is it still rebooting when switching modes?

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Houston, we have a problem :.

I was comparing the room temp and the set temp remotely on the laptop and them from the Android app and it wasn't where I set it.  Went in the coach to look things over and piddled around checking settings and then walked to the shop.  I walked by the coach and heard the basement unit operating.  Went inside and discovered somehow the AC unit was in the cooling mode even though the Si said heat mode.  I changed the reversing valve setting and it was still cooling, rebooted it with no joy.  And yes, we did have another spontaneous reboot on mode change.

It did work yesterday in heat/cool modes.  Today I tested emergency heat (propane furnace) and it works fine fortunately - we have another cold front coming down.  I'll get another one from Amazon and try again.

A little side note, John. Your freezer temp  is still at 67.0 ?. Or is that your well house. 

Excuse my intrusion/


 

Hi Carson - the freezer (in the pump house) is shut off and that temp reading is now the inside temp of that outbuilding.  You can watch it go down tonight - we have another strong cold front on the way tonight  :  .

Back to the Ecobee - replacement on the way from Amazon and I ordered one for the house.  I'm going to split off my Ecobee posts from the Replacing Coleman Mach Thermostat thread - I feel like I've highjacked it.

John,
Have you tested the AGS, or is the thermostat isolated from AGS operation. Seems they were linked for inside temperature control.

The Coleman Mach thermostat (or the Ecobee) have no interface to the AGS.

New Ecobee Si arrived this afternoon and I quickly installed it and programmed it.  Time for the smoke test.  Uh-oh.  :  As soon as it called for heat, it rebooted.  It rebooted on heat in heat pump mode or propane furnace.  Now I'm suspecting we have a 12V power issue so I pulled the Si off the mount and measured the voltage at about 11.5V - not good.  Apparently the Coleman Mach thermostat is happy with a lower voltage and the Ecobee isn't.  I think I can solve the issue by bringing in 12V from somewhere in the OnePlace area. 

The reboot issue was indeed caused by low voltage.  I picked up a better source of 12V and the Si is rock solid, however it still isn't working correctly.  Talked to Ecobee tech support (I'm working with one guy which is a big help) late this afternoon and he's going to look over all of the documentation I sent him tomorrow and email or call me. 

I installed the Si in the house and it's working perfectly (except I blew the 24VAC fuse - the fuse is on the air handler in the attic  :  .)  Had to drag the ladder in the house and go attic crawling.

Any more updates John? Like you, the slide switch to set the proper mode is a pain.

Michael - this is unfortunately still a head scratcher for me - in fact I've spent part of the afternoon working on it again.  Just to be certain we didn't have a spontaneous failure of the heat pump, I wired the old Coleman Mach back in and it works fine which is actually a relief.

Si tech support didn't have much to add other than checking to see if the reversing valve is operating by measuring the voltage across W and RC.

The more I dig and research, the more I understand thermostats and the more I can't figure out why the Si won't completely work.  The principal of operation is basically simple, 12 V DC is sent to the control board on the heat pump to start compressor #1, the fan and depending on if you want heat or cool, the reversing valve will either be energized (in my case the relay is energized for heat.) If necessary, compressor #2 starts for cool mode, for heat mode both compressors are automatically cycled on by the heat pump control board.

I might wait until Duner (Bill) stops by for a visit next week and we can both work on the problem or I might try to have the Si drive 12V relays and then have the relays drive the heat pump control board.  Or I might breadboard up the Si and do some experimenting to be certain of how the Si operates in various modes.  This should be so simple, I do not want to give up.

Just to clarify is it definite that the 'stat will work on 12 VDC. House systems are 24V as you found out with the attic trip.
I have had issues with mili volt gas pilot thermocouples in the past with digital 'stats. Ran them off batteries and changed out monthly

Yes, Ecobee said it will run off 12VDC or 24VAC.  I tried the Honeywell touch screen thermostat that we had in the house and it would have worked since the display was running off batteries but it couldn't do a two-stage heat pump.  It might have run off 12V only but I didn't test that.

I ordered a new control board for the RVP heat pump just in case I want to eliminate that.  BTW, while looking at the board and the start/run capacitors, I noticed one of the run caps was leaking so I've ordered one of those.

I talked to my AC guy this morning, when I said 2 stage with separate propane heat heat, he started laughing and said if I could come up with something that would work, be sure to apply for a patent

;D ;D ;D

Actually it's two stage cooling and one stage heat (heat pump) with auxiliary (W connection) heat, nothing weird or fancy.  The Si should work with the config, Duner got the heat pump to work with another aftermarket thermostat, so I'm hoping I can with the Si.

Was looking through the unit manual today and found two thermostats shown. The one I have is the 6535-3451.
The manual shows another 6335-3351.
Mine has the small slider on the right for setting the temp, the other seems to have two pushbuttons to raise or lower the setpoint. It looks like what I would like to have. Do any of you guys have that model and know if it would be a direct replacement for mine. My wife just don't like the slider claiming she can never seem to get it to the temp setting she wants.

Go to this page on the RVP website and enter thermostat in the search box.  If you have the temperature adjustment slider (analog) model, you should be able to replace it with a Coleman Mach digital version. Note that some of the thermostat models were design specifically for Winnebago.

Well after conversations with Eric Botts at RVP Support, I was advised that the 6536A3351 was an almost exact swap. BTW the 6535A3351 is the same in Black.

I ordered one yesterday from Amazon, to be shipped from Tweety's, for $116.99. I'll let everyone know hoe the installation goes.

Whoo-hoo, broke the code!

I could write a novella about the hoops I've jumped through trying to get the Ecobee Si working (and then my touch screen Honeywell I displaced from the stick house) with the RVP heat pump.  I finally hooked up the Coleman Mach thermostat to 12V and then made an operational matrix (Duner calls it a truth table) - I documented what leads go high (or read +12V) in each mode (off, cool, electric heat, gas heat.)

It was a configuration issue because I assumed the thermostats should be configured as a heat pump, after all the unit is a heat pump.  Well, it is a heat pump with gas backup but that's not how the thermostat interfaces with the heat pump control board.  I'll be documenting this thoroughly later but all I needed to do was to configure the Si as two stage cooling and two stage heat and NOT as a heat pump.  To put the heat pump into electric heat mode, it just wants to see +12v on W and W2 and it doesn't want to see 12V on Y1 and Y2.  Gas heat mode is +12V on W2, W1 is off.  Cooling mode is +12V to Y1 (first stage cooling) and then Y2 (if second stage is called.)

I've got more testing and tweaking to do, but I think it's going to work out quite well.  A nice feature of the Si thermostat is you decide when second stage heat (gas) is going to kick in - you set the temperature delta (difference) of set vs. actual.  With the Coleman Mach, the temperature delta is fixed at 5 degrees, in other words the gas furnace won't kick in until the room temperature is 5 degrees below set temperature.  I'll probably make this 3 degrees.  Or you can configure the second stage to start x minutes after stage 1. << Edit - I don't think that's possible.

How I do admire your patience and stick-with-it-ness, John.

Thanks Bill!  Hate to admit defeat on a tech project.

Great job John, after reading some of your posts I really thought that brick wasn't going to fly! That Coleman is a pain and I will be looking forward to the conversion after you finish your write up.

John, just to let you know, I solved my problem. The 6536A3351 that I ordered turned out to be a direct plug-n-play. No wiring to change, worked great. Note the pantry made a great workbench to support the One-Place panel while making the changeover.

Now wife is happy with digital, maybe I'll get a browny point, but probably just another request. ;D