Thermostat Question for Boiler

[Oggy]

Instead of jumping into something and ending up without heat, I'm trying to do my homework... Only problem is I can't find the resources I need...

Current Setup: R, G, & W wires going into thermostat. This is a boiler setup, with 2 zones. When one zone is needed water flows through a heat exchanger with a fan blowing recirculated air into the downstairs (walk-out basement). Upstairs we have baseboard hot water running the perimeter of the house.

I looked for a "control board" but the house is old, and it looks more like there are relays for the separate zones, rather than a control board for the whole thing. Adding a "C" wire like most of the smart thermostats state, does not appear to be easily accomplished, or atleast not as simple as one would believe from the instructions included.

Future setup: No clue. I'd like to add a smart thermostat, but I also like my life, which my wife would surely take if we had no heat.

What are my options, without replacing the boiler?

 

[Robbie B]

The C wire is your common/24v wire. You can either tap into the transformer supplying your current thermostat provided it’s 24v or buy a thermostat that has battery power like I did and run it that way.

 

[Hobby_Man22]

The C wire is your common/24v wire. You can either tap into the transformer supplying your current thermostat provided it’s 24v or buy a thermostat that has battery power like I did and run it that way.

Can they have both? Or is it only one or another? I noticed I cut the breaker for the whole shop and the thermostat was still on so I know it is battery powered.

 

[Robbie B]

Yeah. You can power them with the 24v and it will use the batteries as backup. I was in a hurry to get my system back up and going when I did mine this past summer. This is the tstat I got. https://www.luxproducts.com/brio/ It was on the shelf at Lowe’s. Your system may or may not be a 24v system. You will need to verify the common voltage but if it’s not just run it off the batteries. You will also need to sort out what dip switches you need set to what on the board.

 

[brewchief]

3 wires to a Thermostat on a boiler system could indicate a 3 wire white rodgers zone valve,compatibility with a smart stat may be more difficult.

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[dogdog]

Post some pictures...of the components involves... which is the zoning valve and the FAN controller on the one with the heat exchanger...

Each zone would needed their own thermostat. but C wire can be found on the zoning valve (they exist in the bird nest of wires)... Only problem is, does your Transformer have enough juice to power the extra fancy thermostats...

Basically you have two choices IMO.. assuming you have no issues pulling the extra C wire to the thermostat(s). If you do, I think echobee have a 3 wire to 4 wire conversion kits or maybe that was a 4 wire to 5 wire... worth looking into.

at least that is how I find them for my friend's 3 zone hydronic system. Not sure, No expert here.

1) identify the C wire at the zoning valve... which is identify R should be easy same as the R on your thermostat, C is the other lead of the transformer out 24V AC... check with the volt meter on AC volt setting.. you should have consistence 24VAC output regardless of system call for heat or not.. (might be 28VAC Rms, give or take but consistence), that is most likely your C wire. pull the wire to the thermostat and you have it done.

you'll have to double check the G wire circuit... this is the fan circuit for your zone that uses heat exchanger... if it is on a different transformer for powering. then you might needed an isolation relay... or maybe your previous installer already did that. Not sure. You'll have to check.

2) use isolation relay and blanket it. for the zone that have G wire, use two isolation relays 40VA transformer should be able to power up all the relays and two of the smart thermostats.

 

[Oggy]

Ok, so I don't see any electronic valves, I have two circulation pumps, a Bell & Gossett, and a Taco. The B&G operates only the heat exchanger, and the Taco the rest of the house.

The brick wall is located in the center of the house, and the thermostat wires come down into the mess you see in the photo, and its difficult to trace anything there. The wires you see with the blue nuts at the top, go into the boiler, and are connected as seen in the boiler photo of the gas valve.

I'm thinking I may need to just look into a programmable, and not a smart thermostat. Or talk to someone who is more familiar with it than I am, and can fix any problems created...

Thank you for all your help!

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[Wrench97]

Do you currently have only 1 thermostat and both the heat exchanger and baseboard run at the same time?

 

[Oggy]

No, 2 thermostats, each controls their zone individually.

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[Wrench97]

Then you'll need a smart thermostat with a remote sensor.

How many wires are running to your current t-stat?

 

[Oggy]

3 wires, r, g, & w. The thermostat we would like to be smart atleast, I haven't checked the other to be certain.

Then you'll need a smart thermostat with a remote sensor.

How many wires are running to your current t-stat?

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[Wrench97]

You'll need 2 wires for the remote, plus 4 for the stat.
If wired conventally
G is the indoor fan on the exchanger
R is 24v power
W is the call for heat
C common usually the black wire but varies
The 2 for the remote.

Edit

That does not account for the zone valve off the remote, I'm not sure how to handle on your system with one stat.

 

[Bert_]

Typically each thermostat controls a zone valve. The zone valve has a contact that signals the circulating pump to run and the burner to fire if needed. The burner is also controlled by and aquastat.

It's hard to tell exactly what you have with what you gave us but it doesn't sound like the typical zone valve set up. Your picture looks like each pump is controlled with a 24V contactor. Guessing there is some more wiring not shown to control he air handler.

 

[Oggy]

I appreciate everyone's help, the air handler is controlled by the switch and fuse box above it (the metal conduit wraps around the brick from center moving to the left of the photo), there are no zone valves, each zone controls its own pump, and can independently turn on the boiler.

As stated by others above, It sounds like this isn't a typical setup. I think when I have it serviced, I'll try to talk to the guy and see what he thinks can be done, rather than messing with it and requiring an emergency call...

Thank you for all the help.

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[dogdog]

Do you wanted to change it into one zone ? or keep the 2 thermostat and 2 separate zone setup with two thermostats ... wifi or not.

Either case.

start with identifying your R W G wires on one zone and R W wires on the other. tag them.

Identify the C wire reference to the transformer with the R wire. on both zoning valves.

Check if your current transformer have enough to power all of your new thermostat(s) and your valves etc. if not upgrade or add new transformer and use isolation relay and separate transformer for thermostat is relays.


EZPZ.

of cause dependent on your comfort level working with these things.

and if you insist in connecting the two zone together. and they share the same transformer, the R and C is the same for both. If they don't then use isolation relay and separate transformer. you can even use the same transformer if it have enough juice to power things.