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thermostat/switching relay conundrum

tyme2par4

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So I purchased a couple wifi thermostats to replace my existing ones. They require a "C" wire for installation, and neither location currently has one. The first floor location has an unused wire, but I'm not sure where to hook it up. The second floor location I should be able to run a new wire to without too much issue.

The switching relays as shown in the picture only have terminals for 2 thermostat wires. There doesn't seem to be any place for the C wire.

On top of that issue, the relay for my first floor zone isn't putting out 24V like all the others. It seems to be 15V between the 2 terminals. But what confuses me more, is the bottom terminal is at about 4.5V when compared to the neutral wire or the box. It seems that the transformer is slightly out of phase with the line voltage?
Any suggestions? Does this sound like a bad transformer? Bad connection somewhere? Is it actually a 12V relay? Should I just bite the bullet and buy a new switching relay? I'm kind of stumped here.

BTW, this is for a FHW oil boiler. 4 zones including the indirect water heater. The first floor is the only one that isn't reading 24-26V
8001778917049033566.jpg
 
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dogdog

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A closer pic or model number of those relay would be nice...

The C wire in general is just the Other Wire off the transformer on the low voltage side..... since it's 24VAC
...

You'll have to determine if your current trasformer have enough juice to power your Wifi Thermostat.. if not then you'll have to go with an external 24VAC transformer and an isolation relay.... simple as that.... but you do have ot make sure you have 3 wires at least to the thermostat where it is mounted.... back to the external transformer...

sorry can't see the pics and not going to stress my eyeballs out trying to see what you have.
 
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tyme2par4

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Sorry, didn't realize the full resolution photo didn't come through. The model number is RA89A 1074.
From
 

dogdog

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Those RA89A only have T & T, I think which is R and W... the C is on the other side of the transformer that is a solder point (when you measure R and W... if you are not getting 24V is probably because it's the transformer voltage (24V) - the voltage drop of the coil(s), the miliamp x resistance of the coil.... = your measured voltage at the T & T .. if you would have measured at that tiny transformer output (one of the terminals and the solder joint) probably it is 24V @ some very low amp) .. not sure if you wanted to mess with it or even know if that tiny transformer can power the Wifi or any thermostat...

I think it is better to get your self a 40VA transformer can power 3x wifi thermostat... if not you can always add more transformer or bigger transformer ... and an isolation for each heating zone that you needed....installation is pretty simple... I did it for a friend in his bird's nest wiring setup simple... like I said still needs at least 3 wires going to the thermostat.. if you don't have it then.......probably going to make it more complicated.

There are standard transformer/relay build in packages for a little more like $30-ish or $40-ish... idea is the same as external relay, and transformer, just everything build into one and packaged nicely just for one thermostat.... so....

Diagram is the same as that ecobee link no matter which brand you choose.
 
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tyme2par4

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Those RA89A only have T & T, I think which is R and W... the C is on the other side of the transformer that is a solder point.. not sure if you wanted to mess with it or even know if that tiny transformer can power the Wifi or any thermostat...

I think it is better to get your self a 40VA transformer can power 3x wifi thermostat... if not you can always add more transformer or bigger transformer ... and an isolation for each heating zone that you needed....installation is pretty simple... I did it for a friend in his bird's nest wiring setup simple... like I said still needs at least 3 wires going to the thermostat.. if you don't have it then.......probably going to make it more complicated.

There are standard transformer/relay build in packages for a little more like $30-ish or $40-ish... idea is the same as external relay, and transformer, just everything build into one and packaged nicely just for one thermostat.... so....

Diagram is the same as that ecobee link no matter which brand you choose.

Thanks, guess I'll have to pick up a transformer.
 

dogdog

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Thanks, guess I'll have to pick up a transformer.

You'll needed a transformer and a relay... there is a few thread about that here....

basically 1 transformer and an isolation relay for each thermostat... or a transformer/relay combo package for each thermostat....

this is what I got for my friend's place... The transformer I got from HD, same brand and model at $50.... amazon lot cheaper. if you are on a 240V system then there is a version of that with select-able 120/240v input....

https://www.amazon.com/dp/B000K2EC7K/?tag=atomicindus08-20

https://www.amazon.com/dp/B000LESCI2/?tag=atomicindus08-20

This was my thread asking for the suggestions...

https://www.garagejournal.com/forum/showthread.php?t=369950


as far as that combo transformer/relay packaged device, I think it was posted here earlier.... maybe that some one can tell you the make/model number.... if you are interested in those...
 
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walta

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Your Wi-Fi thermostats are remote controls.

A remote controlled Jet Ski sounds like fun but a remote controlled Queen Mary not so much.

Most boiler systems like the Queen Mary do not respond well to quick and frequent changes.

Be very careful, most boiler systems assemble from parts supplied by mutable vendors connected differently be each installer so almost every install is different than the next.

Walta
 

dogdog

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Your Wi-Fi thermostats are remote controls.

A remote controlled Jet Ski sounds like fun but a remote controlled Queen Mary not so much.

Most boiler systems like the Queen Mary do not respond well to quick and frequent changes.

Be very careful, most boiler systems assemble from parts supplied by mutable vendors connected differently be each installer so almost every install is different than the next.

Walta

Huh?
 
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tyme2par4

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I wired everything up with the transformer and switching relay, but the new thermostat doesn't seem to call for heat. I confirmed my wiring with my old thermostat before I installed the new one, so the isolation relay wiring should be correct.
Working with the manufacturer on the issue now.
 

dogdog

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I wired everything up with the transformer and switching relay, but the new thermostat doesn't seem to call for heat. I confirmed my wiring with my old thermostat before I installed the new one, so the isolation relay wiring should be correct.
Working with the manufacturer on the issue now.


not sure. what exactly was done at your end. Hope this doesn't confuse more... not exactly a technical writer material... at any point if it is way too confusing... maybe should contact a HVAC guy.......YMMV

It's very simple wiring... assuming you went with the diagram of the isolation relay...
If your old thermostat worked on batteries, it should have only used 2 wires (if it is heating thermostat only), you needed 3 wires for it to work (that is 3 wires from the thermostat to the transformer/relay then two wires from the relay contact side to the T*T of the RA89A.

hook it up as you see on the diagram, not as you see on the old thermostat... I don't think it is the same wiring as your Old thermostat, if you choose to go with isolation relay... the battery operated thermostat worked a little different than the ones that worked off 24Vacs...








Here is how I would have logically looking at it. Not sure what Thermostat you installed and with nothing hooked up to your RA89A's T&T yet....

You have a 24vac output transformer, that have output 2 leads (the 120V inputside, you know it is just Line and neutral), take any one of the output leads and label it as R (or RH/RC or just R)... and the Other output lead label as C... those two wire goes to your new thermostat. R and C...

Now find another wire that also goes to the thermostat and label it as W1.. this wire goes to your new thermostat and W1...
and at the transformer/relay end.... this wire goes to the Coil side of the relay... lets say the common (White/Yellow) if you have the RIBC...

At the transformer/Relay end... take the other coil side of the relay (for the RIBC it's white/blue) hook it up the the transformer output your just label C... for common...

on the relay contact side, you would needed the NO and Common ... (for the RIBC it's Yellow for common and Orange for NO.) Hook those to the T*T of the RA89A (but leave it unhooked during trouble shooting) , It should have continuity if the thermostat calls for heat and no voltage or anything between these two leads....




1) is your thermostat powers up with R (maybe it is RH/RC) and C... if yes then your R and C is ok...

2) when your thermostat calls for heat... put a multimeter on AC voltage setting and measure voltage between W1 and C... do you get 24-ish volt... if Yes then your thermostat calls for heat... if no... maybe it should be on a different terminal ? Check which ? have 24V ?

3) since the W1 (lets say it's W1) and C just connects to the coil side of the Relay... (the 24V coil, not 120V coil, *some have dual voltage).... when it is is connected and the thermostat calls for heat, you should see 24Vac between the W1 and C... did the coil of the relay clicks... if you bought that RIBU1C relay, the LED should have lid if it is activated. or sees 24VAC at the coil...the coil side of the relay should be (white/blue, and white/yellow)

4) If step 1 to 3 are good... then check if the relay side between the Common / and NO wire... does it have continuity... if it has continuity.... then the setup is good and you can hook up the contact side of the relay to T&T on the RA89A doesn't matter which T to which relay contact, just have to be the Common and NO... for the RIBU1C yellow wire is the common, and orange is the N.O. and you are capping or tapping up blue, white/black... those two wires are not used.

If you don't see your thermostat power up check the R, see which R you should be connect to some times it's RH... some times they wanted you to jump R and RH... dependents on the thermostat...

If the thermostat calls for heat, and you don't see any 24Vac between the W terminals, then you should call your thermostat company...

If your relay didn't click just make sure you got the right coil... for the RIBC it's white/yellow white/blue.

If you don't see continuity on the contact side of the relay when it has power on the coil... maybe you mixed up the NO and common and NC and common ........

If all steps are verified, then, you'll have to look at the RA89A, putting a jumper across T&T should call for heat... if it does, then maybe your wiring have problems.

Pretty sure you can pick up from here...
 
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tyme2par4

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All of the wiring was fine. Turned out it was just a minor glitch in the thermostat and needed to be reset.
 

LS6 Tommy

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You'll needed a transformer and a relay... there is a few thread about that here....

basically 1 transformer and an isolation relay for each thermostat... or a transformer/relay combo package for each thermostat....

this is what I got for my friend's place... The transformer I got from HD, same brand and model at $50.... amazon lot cheaper. if you are on a 240V system then there is a version of that with select-able 120/240v input....

https://www.amazon.com/dp/B000K2EC7K/?tag=atomicindus08-20

https://www.amazon.com/dp/B000LESCI2/?tag=atomicindus08-20

This was my thread asking for the suggestions...

https://www.garagejournal.com/forum/showthread.php?t=369950


as far as that combo transformer/relay packaged device, I think it was posted here earlier.... maybe that some one can tell you the make/model number.... if you are interested in those...

x2 on the isolation relay. The RA89As are a combination control. They each have a built in transformer and a relay. In order to work around getting an isolation relay and a separate transformer, you'd need to get to the C side of the transformer and get it wired to the thermostat.

Tommy
 
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