[[email protected]]

Progress! Mostly… I think I have the wires connected correctly but when I try to attach the 12-volt wire (yellow/black for bedroom - going to the labeled terminal strip) the aquahot comes to life and the pumps start running but I have not turned on the Ecobee yet! The yellow/black wire IS connected to the Ecobee. Maybe I have the two yellow wires backwards… will it hurt anything to just switch them? Not sure why the yellow/black wire is sending out 12-volts but I checked it with my meter and it was…

The wire coming from the thermostat should be coming from the terminal strip at the top. But yes you can swap those, the one coming from the thermostat should not have any voltage. Remember that you have to change your meter to AC to read the 24v from the thermostat, and DC to read the 12v for the aqua hot. Does the relay click on when you connect the wire?

[pairodice]

I did verify that I am getting 24v on the W1 wire when the thermostat calls for heat. When I connect the thermostat up when heat is called for the fans come on in the bedroom (which I’m testing) and the pump #1 (closest to engine) comes on as I think it should. I’m going to run the AH on electric heat for a while and see if I can feel any heat coming out of the kick fan. 
No idea what all the other Red and green wires maybe 14 ga.? Are for…but they do have voltage to them from somewhere…

[[email protected]]

I did verify that I am getting 24v on the W1 wire when the thermostat calls for heat. When I connect the thermostat up when heat is called for the fans come on in the bedroom (which I’m testing) and the pump #1 (closest to engine) comes on as I think it should. I’m going to run the AH on electric heat for a while and see if I can feel any heat coming out of the kick fan. 
No idea what all the other Red and green wires maybe 14 ga.? Are for…but they do have voltage to them from somewhere…

So the red and green wires to the old thermostat provided the 12v to the old thermostat. If I remember correctly the red was the 12v positive and the green was the common or negative. You can meter it to confirm. You may want to connect the common to your new t stat but I would just cap off the 12v positive(red?).

[pairodice]

I connected everything up and the tstat will turn the pumps on but when I turn the tstat off the pumps don’t respond - I let them run for about 15 minutes before disconnecting. I am getting 12v DC on the AH side of the relay but 4v AC on the others side. I’ll check it again in the morning :-(

[[email protected]]

I connected everything up and the tstat will turn the pumps on but when I turn the tstat off the pumps don’t respond - I let them run for about 15 minutes before disconnecting. I am getting 12v DC on the AH side of the relay but 4v AC on the others side. I’ll check it again in the morning :-(

You need to double check all your connections. If you have the 12v going to the new tstat that might be your issue.

[pairodice]

I re-validated that:
1) with my multimeter on AC: If I connect the Black © wire and Yellow/black (W1) wire (Face of Ecobee pulled off): 27v AC
2) with my multimeter on AC: If I connect the Yellow/black wire to W1 wire with TStat OFF: ~4v AC
3) with my multimeter on AC: If I connect the Yellow/black wire to W1 wire and connected ground to the black © wire and the TStat ON I do get ~28v AC
2) I tested the yellow/black wire in the AH bay with my multimeter set to DC and the TStat ON; the wire going to the AH showed ~4v AC… not sure why the wire is not getting the full 28v to the transformer…
Question: when testing the yellow/black wire from the TStat (in the AH bay) I am connecting the ground on my meter to the a screw in the side of the AH unit - should this work for AC?
I can create a quick video of what I’m seeing if that helps… hopefully I typed in everything correctly.
I will try to run a wire out the window to get a good 24-volt ground from inside the coach at the TStat…

[pairodice]

IT WORKS!!!! Just for grins I decided to plug the GREEN wire near the TStat in to the ground © wire and the AH pumps hummed to life! Then when I turned OFF the TStat the pumps stopped running! Now I’ll test it with the Diesel AH and see if anything explodes :-)

[pairodice]

So it dawned on me (which I’m sure Richard and Jeff also said but I ignored - sorry guys): the TStat is only for turning on the zone pump and the toe kick fans. The heat in the AquaHot tank is separate - it is controlled either by the Diesel boiler or either of the 110v/220v electric elements inside the AquaHot tank.
I now know a LOT more about how the A/C and heat systems work… I don’t think I’m ready to replace gurus like Rudy but I’m learning!
BIG thanks to Richard and Jeff for all their advice and loss of hair while working with me!
Now I need to test the whole thing with the A/C units! I’m sure I will find other stuff along with needing to fix some leaking AquaHot pumps…

[[email protected]]

So it dawned on me (which I’m sure Richard and Jeff also said but I ignored - sorry guys): the TStat is only for turning on the zone pump and the toe kick fans.  The heat in the AquaHot tank is separate - it is controlled either by the Diesel boiler or either of the 110v/220v electric elements inside the AquaHot tank.
I now know a LOT more about how the A/C and heat systems work… I don’t think I’m ready to replace gurus like Rudy but I’m learning!
BIG thanks to Richard and Jeff for all their advice and loss of hair while working with me!
Now I need to test the whole thing with the A/C units! I’m sure I will find other stuff along with needing to fix some leaking AquaHot pumps…

Ahh yes that is a good point, the t-stat should only be turning on the zone pump and the associate heater core fans. FYI the zone pumps can also be shared by other t-stats for your bathroom, closet or even basement heat that can call for a zone pump to run. It just depends on how they configured the zones. I need to figure out which ones do what on mine, I have not bothered yet to figure it out. 

As you mentioned the aquahot boiler temp is purely regulated by snap discs located inside the aqua hot, there is one for the AC element and one for the diesel side. Its good to know about these, they can sometimes be an issue. So you are correct that the diesel burner is not going to kick on immediately when the t-stat calls for heat. It will eventually turn on once the temp inside the boiler drops to the set point of the snap disc.

[pairodice]

Working on the front tstat; everything looks and tests fine inside but if I turn on the tstat calling for heat, when I put my multimeter on the DC AH side I get nearly 20-volts DC ??? Is that right? I can hear the pump working but no kick fans…