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[hondaracer2oo4]

I need to cut my pump on my owb from circulating when the oil burner thermostat in the house calls for heat. The most simple way for this to be accomplished that I can think of is to have the oil burner thermostat trigger a 24 volt relay out at the owb which would break the power from the pump. My question is will I need to buy a 24 volt transformer to trigger the 24 volt relay with the thermostat or can I somehow use the 24 volt transformer built into the oil burner controller? Thanks.

[slimjim]

Honda Yes you can use just the TT wires and transformer to make and break a relay but there is not enough power to run zone valves and such off the transformer on the oil burner, there is a better way, help me understand your system a bit, you want the circ to shut down when the oil is used right? Why wouldn't you simply unplug it or shut it off in the summer months and use an aqua-stat on your incoming wood boiler lines to kill the oil burner when the wood boiler goes out to protect your lines. Any simple break on rise/ make on drop,strap on aqua stat can be used to do this.

[hondaracer2oo4]

Slim, thanks for the reply. I actually stopped by your place a couple Fridays ago (7/30) in the afternoon as I was passing through, you weren't in the shop though so I continued on. Not before looking through the boilers though on my way out. Anyway my system currently is very simplistic. Circ runs 24/7, OWB thermostat calls for heat which turns my FHA blower on and off through a Honeywell YHR845A1030. What I need to happen is that if the OWB has some sort of problem when I am not home my wife can simply turn the OWB thermostat down to a low temp and turn the FHA oil burner thermostat up to the desired temp and the oil burner will take over. When this happens I need the circ on the OWB to shut off everytime the oil burner fires(or ideally when the FHA blower is running). I have found that if I run the oil burner with the OWB circ moving water through the water to air hx that the cool water extracts the heat from the FHA oil burner providing only luke warm air from the vents. My thought was to simply run the circ on the owb off of a relay that is normally closed, but is opened when the FHA oil thermostat calls for heat.

The second project that I am trying to tackle is putting a Honeywell L6006C1018 strap on low limit aquastat on the feed line from the owb to shut down the blower on the owb when my water temp drops below a certain amount to save the coals. I am away from the boiler for long periods of time sometimes(14-15 hours) and come home to an empty boiler and cool water. I then have to restart the boiler and get the temp back up. I would like to save the coals so that it can easily be restarted. My thought is the Honeywell L6006C1018 run in parallel with a simple 60 minute bathroom timer. When the temp drops below a temp the aquastat kills the fan, I then feed the boiler and turn the timer to 60 minutes and walk away. Sound like I am on the right track?

[slimjim]

  I sure wish I had been home, I could have explained it far better in person over a cold adult beverage but the same aqua stat that you are using to kill your blower can be used to kill the oil burner motor simply by using the break on rise terminals instead, it breaks on rise with the R+B terminals, place it on the incoming wood boiler line and wire it to interrupt the burner circuit on the oil unit, Glad you are doing that on your wood boiler, I have been promoting it for years, it works great with gassers to keep the ceramics hot!

[hondaracer2oo4]

Slim, I am not really following you on using another strap on aquastat and killing the oil burner motor? My goal is to kill the circ pump for the owb when the oil burner thermostat calls for heat(or when the Fan limit switch flips the FHA blower on for the oil burner).

[hondaracer2oo4]

What I am now thinking is that if I can use the fan limit switch to switch a relay, which goes through a 24 volt transformer, sends 24 volt power to owb, second relay at owb which cuts pump on and off that would be best?

[slimjim]

I don't understand why you would want the circ connected to the tt on the hot air unit, doing that will give you no protection from freezing your lines to the wood boiler in the winter months when backup heat is required, it is possible to do, I just don't understand why you would wish to do it

[hondaracer2oo4]

I need the owb circ to stop circ water when the oil burner is running. If I don't stop it from circ water when the oil burner is actively firing trying to meet the thermostats call for heat the water circ through the water to air hx will cool the air down and not allow me to heat the house. When the oil burner thermostat is satisfied then the owb circ will be re energized and circ water to protect lines from freezing.

[slimjim]

Ok I can understand that theory, can you run a TT wire out to the boiler? if so this will work

[hondaracer2oo4]

I edited my previous stupid response after I looked more closely at the wiring diagram for the 501, duh! So this is my thought. It would be most simple to just hook the 501 up to the oil burner thermostat with thermostat wire and cut the circ when the burner fires. My thought though is that even though this is a back up situation that I may want to do this a little bit better. I think that the best option would be to cut the circ when the FHA burner fan is running which would be switched by the Fan Limit control. This is line voltage though. So I would need to send the line voltage from the Fan Limit to a 24 volt transformer, then to a Relay out at the owb to control the circ pump. Would it be worth the hassle to buy these two parts separately and wire it this way? I believe that any 24 volt transformer should work and any relay with a N/C position and a break on signal relay should work?

This is what I have which I think will work for this application. White Rogers 90380 SPDT with  N/O and  N/C contacts. http://www.supplyhouse.com/White-Rodgers-90-380-Fan-Relay-Type-184-24-VAC-Coil-50-60-Hz-SPNO-SPNC-Coil-Data-77-Ohms-DC-Resistance-125-mA?gclid=CIGr2u3EwL8CFUIQ7AodQ2YA-Q
And Transformer http://www.supplyhouse.com/White-Rodgers-90-T40F1-Transformer-40VA-60-Hz-120V-Primary-24V-Secondary-Foot-Mount-14927000-p

I am confused with the transformers, there are a lot of different model transformers but I can't figure out the difference?

[RSI]

Other than the VA rating, there probably isn't really that much difference between them.

What turns the blower on for the OWB heat? You will want to make sure the that it doesn't interfere with the OWB operation.

It would probably be easiest to just run off the wall thermostat instead. Just run wires from the W and C in the furnace out to the OWB and connect them to the coil on the relay. Then if you connect the pump the the normally closed contacts it should shut off the pump every time the oil burner fires.

[hondaracer2oo4]

I assume you mean the FHA blower in the house when you ask about the blower for the owb? If so that is triggered to turn on by a second thermostat inside that powers the blower through a Honeywell transformer/relay.
So as far as cutting the pump for the owb you think that it is not worth the extra effort to kill the pump when fan limit switch calls for heat on the oil burner? You think I should just cut it out when the burner is actually firing?

[slimjim]

Yes that's it!

[hondaracer2oo4]

Alright, thats what I will do then. Ill only get the relay and run the thermostat wires off the oil burner out to the owb and make the connections out there. Thanks.

[RSI]

I would try it that way and if you don't like the way it works you can add a transformer later and just move the wires.