Oil Burner Wiring Question

dan holmes_3

Use an sr502 relay not two 501s.That way you can send 24v up the comon wire usually the white but could be any of the three.Feed back down to each t post on the relay.You get the feed from the 24v aux terminal not from tt there will only be a wire on one post of the tt terminals for each zone.Do it all the time.

Tony Massi

Oil Burner Wiring Question.

We are replacing a boiler. The old bolier has line voltage thermostats and controls. The thermostats are wired with 3 wires. On is red one is black and one is white. The red one sends power to both therms and the black and white send it back to the circulators. The power and neutral wires are seperate powering the burner and the other controls. The question is can we use a Taco SR502 switching relay for this job or any other switching relay. I know that we can use zone valves for this we have done it before. I don't think you can share a thermostat wire when using a switching relay. Thank You.....

John@Reliable_5

Sure you can.............

Just use the "old" wiring to thermostat to carry your new 24 volt system from the switching relay to new thermostat.
You only need to use two wires now, leave the third for later use if ever needed.I would cut old wires at floor joists and run new 18ga wire to panel.Only line voltage needed would be power to panel, them out to pumps. But the best way I think would be to replace all the 14ga wire with new 18ga thermostat wire, use the old wire to pull in the new wire from panel to thermostats.

jim lockard

sounds like

Johns got the answer run it all new in 18 gauge

Tony Massi

Thank you both for your reply. Your right if you could easily replace the line voltage wires with low that would be the thing to do. But its a 2 story house it would involve running new wires, maybe hiring an electrican. We would rather use the 3 line voltage wires over and use a switching relay if possible.

Robert O'Brien

Wire the conductor from each t-stat to a RIB relay and use the NO wires to the T-T of the switching relay

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superMARKet

Do you mean...?

Do you mean that you've only got three wires total between the boiler room and all of the thermostats? Like a single run of 14-3, with red supplying hot to both thermostats, and white and black each coming back from a single thermostat and connected directly to a circulator?

If that's what you've got, there's a way to make it work without pulling any new cable, but it's a little bit unconventional and I wouldn't advise it unless there's really no better alternative.

One thought is to dedicate the existing 14-3 to the second floor thermostat (even if only two of the wires make it up to the second floor, just ignore the third wire in the boiler room) and run a new 18 gauge cable for the first floor thermostat.

Tony Massi

RIB Relay

What do you mean by a RIB relay and the NO wires to T&T ?

Robert O'Brien

It's a double pole relay,The tstat will make relay and close the NO{normally open} leads.You wire the hot to the existing common T-stat lead.Then the return from each Tstat to it's own RIB relay.Then the NO leads from relay to the T-T terminals.The tstat remains line voltage check following link http://www.functionaldevices.com/

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Mt. Falls Mikey

Well, back in the day...

We did several of these conversions using the 'ole reliable Honeywell RA-832A.. Sometimes we saw this thermo cable mfd. like BX cable

lectricfave

How about

If your wiring type is RX how about using the bare grounding conductor as your missing wire. In other words red,black to one thermostat,white bare to the other. Remove the bare wire from the ground screw [if you have metal boxes] and wirenut a pigtail to it or slide a piece of insulation stripped from another wire over it. You should not need the bare wire to the box of if you are converting to 24 volts. Be sure to set your heat anticipator with an amprobe.