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shawnmd 10-20-2010 12:01 PM

Wiring a Honeywell RA89A Relay
 
2 Attachment(s)
I am wiring a new Honeywell RA89A relay to turn an oil boiler on and off. The controller for this relay will be a single aquastat on a wood boiler. When the wood boiler is up to temp, it will send power to the relay to shutdown power to the oil boiler burner. Effectively, shutting down the oil boiler when the wood boiler is burning.

The manufacturer of this wood boiler recommended the Honeywell RA89A relay. I am having trouble wiring this relay. It has two TT 24V contacts for a thermostat controller. Because this relay will not be controlled by a thermostat 24V connection, but rather by a 120V line controller from the aquastat, i have jumpered the two TT connections.

I also have the black hot wire coming from the aquastat connected to connection 1 and the white wire from aquastat connected to connection 2. This works, as I can turn the relay on and off (open and closed) using the aquastat temperature dial.

Now for the load (oil boiler burner), I simply snipped the red wire coming from the B1 connetion on the oil burner triple aquastat going to the burner, and ran one end to the relay and the other end to the relay. I was thinking that the relay would then connect and disconnect the power to the oil boiler burner. But where do I connect the load (oil boiler burner) on this relay? From the attached wiring diagram it looks as though I would connect the load to connection 2 and 4. But that would put the line and load on the same connection (2) when I really need these two circuit's to be separated. I have tried using connections 3 and 4 but they have no power regardless of if the relay is opened or closed.

How do I connect the load? Will this relay even work or did they recommend the wrong one?

The first diagram is for the wood boiler and shows how the relay is setup in the wiring scheme. The second diagram is the wiring diagram for the relay RA89A.

beenthere 10-20-2010 04:09 PM

The red wire you cut. You should run a wire from it to the #3 terminal of the relay, and then back from the #4 terminal of the relay. This will break the burner circuit.


PS: Remove the jumper from between Terminal 1 and 3.

shawnmd 10-20-2010 06:05 PM

Quote:

Originally Posted by beenthere (Post 520257)
The red wire you cut. You should run a wire from it to the #3 terminal of the relay, and then back from the #4 terminal of the relay. This will break the burner circuit.


PS: Remove the jumper from between Terminal 1 and 3.


I have tried tying into three and four with the red wires from the burner, but am not getting any power through those leads. This is what is frustrating me. I have the relay working, but nothing through 3 and 4.

beenthere 10-21-2010 12:28 AM

The red burner wire is only energized when the thermostat is calling for heat. Did you have your thermostat set up high enough to call for heat.

shawnmd 10-21-2010 05:53 AM

Yes, I did have the thermostats turned all the way up. I am actually taking the RA89A back and exchanging it for an RA889 with a NC contact.

beenthere 10-21-2010 06:28 PM

But you want a N.O contact.

shawnmd 10-21-2010 06:52 PM

Actually no, I would want a normally closed so when the wood boiler is not running, and the aquastat is not sending power, the oil burner will run throught the normally closed connection.

beenthere 10-21-2010 06:58 PM

We generally use a reverse acting aquastat. Open on temp rise.


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