My wife and I just purchased a condo to lease out as a rental unit. I would like to replace the old 70s (or possibly before) era thermostat with at least a nicer looking unit. What we have now is something like this:
The only difference is that the switch on the right side is in the middle of that column and it is marked HEAT - OFF - COOL. There are no other switches (so no fan selection switch.)
Taking the thermostat off the wall, I see there are three places the wires from the wall connect to the thermostat: Common, Heat, and Cool. This image found on the internet is pretty much the same as what I see on the back:
What can I replace this thermostat with? I seem some nice line voltage thermostats out there, but they all seem to be heating-only. The Mysa smart thermostat looks nice and modern, but I don’t think the wiring syncs up.
I feel like this should be pretty straightforward, and I’ve installed low voltage thermostats, from regular ones to smart ones where I had to also do some wiring at the heater, but never this. Of course, for this one, I am doing the work with the power cut to the unit.
What am I able to replace the thermostat with, and how do I wire it, knowing which wires correspond to common, heat, and cool?
ETA: Or could I/should I convert the line voltage to low voltage via a switching relay?
I was thinking of the Mysa, but it looks like it does electric Heating only.
You appear to have a T694 variant that controls a fan coil. Can you confirm?
I actually don’t know. I’m not at the condo right now and I didn’t pay much attention to how everything was set up as the floors are the priority now. I’ll take actual pictures in a day or two, unless I happen to make it out there again tonight for more measurements.
The way it was described to me, and forgive my ignorance as I’ve never dealt with condo heating and cooling before, does seem to match what Im reading about fan coil systems.
It’s in the inspection: 2-pipe fan coil HVAC.
With a fan coil you are just supplying power to the fan and possibly a solenoid valve that brings hot water from the central boiler or cold water from the central chiller. Check what the system is first and then take a look for suitable thermostats. I know all the standard Nest/eco bee types are out since they are all ultra low voltage.
Yeah, I’m just confused as to what is “suitable” for that set-up. I was just hoping to find something that had the same 3-screws on the back marked Heat, Cool, Com, but there’s nothing like that so far as I can tell, and I don’t know what goes into what. Can I do this with a relay and step it down to a control voltage and use any of the usual thermostats?
I’m not sure what you could do without overcomplicating it.
Yeah, I mean, the current thermostat works, so I don’t need to do anything–it’s just how darned ugly and big and boxy it is.
ETA: Actually maybe something like this would work:
Ok. Looking at it today, there are only two wires coming out the wall. The cold wire is connected internally. This feels like it should be simple.
This is the one we have:
I mean, all the thermostat needs to do is send an on signal when the temp is above or below a set temp when it’s in heat or cool mode. Whether the HVAC is heating or cooling is set by the building, right? Something should swap in pretty easily I would think but I don’t know what works.
I’m not sure if this will be a useful answer.
Try contacting the HOA/managers to find out what they recommend for thermostats. You are certainly not the only unit that ever wanted to get a replacement thermostat.
As you just bought the place, this will give you a good low-stakes excuse to talk to the HOA and find out if they’re reasonable and helpful, or obstructive and petty.
If you’re feeling particularly extroverted, you can talk to the neighbors and see what they have.
The management t is great, but the woman I talked to didn’t know, nor did the one maintenance guy, but I can try the engineer. All I know is I’m allowed to change it as the thermostat is ours. The neighbors probay won’t help as they are young renters mostly.