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Discussion Starter · #1 ·
Baseboard Heat, Forced Air AC.

Once every few weeks all winter the upstairs doesn't stop heating til I cut the boilers power for a few hours. This happened 5 times total.

The thermostat in this zone (honeywell pro) was installed with the new AC <2years ago

I was going to install a new thermostat but see the jumper don't match.

The boiler is connected to red and white wires

Thermostat:
Yellow goes to W
White goes to Y
Black goes to R
Red goes to RC

will something bad if I change them back?
would it have worked at all if they were installed wrong?

87822662_2506169089634242_7070034576063594496_n.jpg
 

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The stat in the picture doesn't use a extra jumper, just gets switched to two wires.

What do you mean, change them back?

Just follow the instructions that came with the new stat. The ones with an external jumper, you usually don't remove.

There's a high chance the stat is just fine and the problem is elsewhere. You don't need to replace to figure that out.
 
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No need to start replacing random parts chasing the issue. Diagnose the parts you have.
Replacing random parts costs time and money. And sometimes leaves you with equipment that’s still broken.
 

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Could be a stuck open zone valve, relay or controller if applicable.
 

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Discussion Starter · #5 ·
The stat in the picture doesn't use a extra jumper, just gets switched to two wires.

What do you mean, change them back?

Just follow the instructions that came with the new stat. The ones with an external jumper, you usually don't remove.

There's a high chance the stat is just fine and the problem is elsewhere. You don't need to replace to figure that out.
This thermostat, the old thermostat, the new thermostat all say for example

White jumper goes to the W terminal and is for heat. Mine has the yellow jumper going to the W terminal. So follow the manual, OR leave it setup backwards.
 

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Discussion Starter · #6 · (Edited)
No need to start replacing random parts chasing the issue. Diagnose the parts you have.
Replacing random parts costs time and money. And sometimes leaves you with equipment that’s still broken.
Yup, its either the control board or the thermostat. One is super cheap and easy to replace the other isn't. But just the service charge for an HVAC to come look at it costs 5x more than a new thermostat.

(and Im not sure how much good it will do when the system is working fine)
 

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what color are the wires connected to the furnace? they should correspond to the same colors attached at the thermostat. the actual colors do not matter. for example the black wire in a thermostat wire bundle is generally connected to the B/O terminal in the furnace. you do not have a typical thermostat wire bundle. you would need to look in the furnace and see if the yellow wire is on the w or y terminal and the same for the white wire. just make sure the wire is connected to the same terminals in both the furnace and thermostat and you should be ok.
 

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no furnace - this is a zoned hot water system system.
 

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no furnace - this is a zoned hot water system system.
Then check them at the boiler. The wires are labeled there as well.
Either someone didn't care when wiring or you have a splice somewhere.
Write down where the 4 wires go on the boiler first then see if that corresponds with the wires on the thermostat.
Don't assume anything or you will / can burn up a control panel.
 

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The a/c is using the transformer in the air handler and the hydronic system has its own transformer. You must not interconnect them with a jumper lest you risk damaging some of the components and possibly the
transformers as well.

The way it's wired now, the heat mode is using dry switching contacts of the thermostat which means the boiler has its own transformer. If it worked before, it obviously was wired correctly. If the boiler is connected to a red and white wire, then the black and yellow must connect to them at some junction.

The colors must be mismatched somewhere make things work correctly. Don't change them unless you want to risk damaging things.

Does the a/c work properly?
 

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Then check them at the boiler. The wires are labeled there as well.
Either someone didn't care when wiring or you have a splice somewhere.
Write down where the 4 wires go on the boiler first then see if that corresponds with the wires on the thermostat.
Don't assume anything or you will / can burn up a control panel.
It's zoned so the wires could be going to a separate control board or relay outside the boiler.

The problem is probably not the stat and the op should use a meter to figure out what's really happening or call a pro.

Could be anything like a failed circulatory pump, valve, zone controller, bad connection, etc.
 
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It's zoned so the wires could be going to a separate control board or relay outside the boiler.

The problem is probably not the stat and the op should use a meter to figure out what's really happening or call a pro.

Could be anything like a failed circulatory pump, valve, zone controller, bad connection, etc.
Yup, randomly changing parts with no diagnosis rarely works out very well. Usually the owner winds up out the money of the parts and has nothing to show for it other then equipment that’s still broken.
Even if parts are .99 cents, never start changing things chasing problems. Use your meter and diagnose first.
 

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Discussion Starter · #15 ·
The a/c is using the transformer in the air handler and the hydronic system has its own transformer. You must not interconnect them with a jumper lest you risk damaging some of the components and possibly the
transformers as well.

The way it's wired now, the heat mode is using dry switching contacts of the thermostat which means the boiler has its own transformer. If it worked before, it obviously was wired correctly. If the boiler is connected to a red and white wire, then the black and yellow must connect to them at some junction.

The colors must be mismatched somewhere make things work correctly. Don't change them unless you want to risk damaging things.

Does the a/c work properly?
As far as I know the AC worked on a program, I do recall a few times where it wouldnt cool if I manually changed it (but that could be totally unrelated). Either way at least 95% the system does what it should.

Anyway, you answered my question. On the old, current, or any new thermostat always wire it the way its wire now, not as per the instructions. (ie connect the yellow wire into the white port on the thermostat etc)
 

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Discussion Starter · #16 ·
Any updates OP?
Messing around with this stuff is weekend task, hence no update, I did return the new thermostat, I would still like to put in the old thermostat that I know worked fine since.

Im not sure how I can use a meter 'to test which 2 wires are for the boiler and which 2 are for the AC, wouldn't both pairs read 24v. Google was no help, and I have a feeling this might be over my head unless you mean use a meter to test the thermostat itself is working next time it wont stop heating which won't happen for weeks.
 

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Yes, use your meter to test the system when it fails to operate.
You definitely don’t want to start replacing parts, like the thermostat, chasing the issue.
 

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Im not sure how I can use a meter 'to test which 2 wires are for the boiler and which 2 are for the AC, wouldn't both pairs read 24v. Google was no help, and I have a feeling this might be over my head unless you mean use a meter to test the thermostat itself is working next time it wont stop heating which won't happen for weeks.
You should call someone out when it fails then.
 

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Discussion Starter · #19 ·
You should call someone out when it fails then.
Yeah, the boiler is 56 y/o. once winter is over I'm getting it replaced, and the entire system inspected.
The $140 visitation fee is a big deterrent when IDK if theycan even find the problem when the system back to normal by the time they come.

(I turn the boiler temp down to 135, cycle this thermostat to off, unclip it from the wall, leave it like this for a few hours, eventually the pump stops pumping and It fine again)
 

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Discussion Starter · #20 · (Edited)
Update, on out front door home security camera I can see when the HVAC guy replacing the thermostat (w/o the boring dtails) it took him a few min tos et up the T-stat, spent 5min giing back and forth to the vent and thermostat (like it isnt working), the then spent 70min taking it on and off a bunch f times messing with w messing with the wires til it finally worked,

Evidence enough that it is wired backwards on purpose.
 
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