how to connect wires for vapor stat to a backup pressuretrol

tumbz

Hi guys!

So i installed a vaporstat and i want to use my pressuretrol as a back up. i will have both on individual pigtails.

i never wired this before so can you show me exactly which wires goes to what?

So i had 2 wires on my pressuretrol and i just switched it to my vapor stat on the R & B.

I know i need extra wire which i took a picture of. can you tell me if my wire is correct?

Please walk me through EXACTLY which wire goes where so the pressuretrol can be the back up...

THANK YOU SO MUCH!

EdTheHeaterMan

The wire on the pressure control to the right is at least 16 gauge but I suspect it is 14 gauge. That is usually used on 115 volt circuits. It can also be used on 24 volt circuits. The wire you show in the second photograph can only be used on a 24 volt circuit. You must verify he voltage is below 30 volts in order to use that wire

EBEBRATT-Ed

Take one wire off your vapor stat. It doesn't matter which one. Run a new wire from the now vacant terminal on the vaporstat to one of the terminals on the pressure control, doesn't matter which one.

Cut the connector off the end of the wire you removed from the vaporstat. Splice a new wire onto this wire and run it to the other terminal on the pressure control.


I don't know if your controls are carrying 24 volts or 120 volts (looks like 120 volt) If it is 120 volt you need to use flexible metal conduit with building wire rated for 600 volts.

You can buy a duplex conduit connector to put in one of the controls so it will accept 2 flex conduits

You can't use the 24 volt bell wire in your hand for 120 volt

You should install the controls straight up and down

Make sure both controls work when you are done

Your safety is at stake

EdTheHeaterMan

This is the wiring diagram. All the limits are wired in series. If the controls are wired with 115V. circuit, you should use the proper connectors and place all the covers on the controls and junction boxes

Jamie Hall

To which I might add -- if you aren't absolutely positive that the circuit is 24 volts, assume it is 120 volts and proceed accordingly. Also assume that if you haven't pulled the fuse or circuit breaker to the boiler that the circuit is live, which is no fun at all.

tumbz

can i test the voltage with my multimeter? i set the multi meter to volts? i have one but dont even know how to use it. HAHA.

i set it to volts and just touch each wire with the 2 leads?

tumbz

EBEBRATT-Ed said:

Take one wire off your vapor stat. It doesn't matter which one. Run a new wire from the now vacant terminal on the vaporstat to one of the terminals on the pressure control, doesn't matter which one.

Cut the connector off the end of the wire you removed from the vaporstat. Splice a new wire onto this wire and run it to the other terminal on the pressure control.


I don't know if your controls are carrying 24 volts or 120 volts (looks like 120 volt) If it is 120 volt you need to use flexible metal conduit with building wire rated for 600 volts.

You can buy a duplex conduit connector to put in one of the controls so it will accept 2 flex conduits

You can't use the 24 volt bell wire in your hand for 120 volt

You should install the controls straight up and down

Make sure both controls work when you are done

Your safety is at stake

is this correct? you made it easy to follow....

Jamie Hall

That will work. However, I agree -- that looks like line power (120 volt) wiring. If so, you must use not less than 14 gauge -- preferably 12 gauge -- wire in conduit - that flex metal cable -- and the conduit must be fastened correctly, with the correct fittings, where it enters and leaves the control boxes.

And turn off the power.

And no, you don't just touch the two probes to the wire to measure voltage. One probe on the wire or terminal, the other to the opposite side of the circuit or to ground. And be careful not to short something out with the probes.

tumbz

Jamie Hall said:

That will work. However, I agree -- that looks like line power (120 volt) wiring. If so, you must use not less than 14 gauge -- preferably 12 gauge -- wire in conduit - that flex metal cable -- and the conduit must be fastened correctly, with the correct fittings, where it enters and leaves the control boxes.

And turn off the power.

And no, you don't just touch the two probes to the wire to measure voltage. One probe on the wire or terminal, the other to the opposite side of the circuit or to ground. And be careful not to short something out with the probes.

so i will use my multi meter and touch something metal to ground on 1 probe and one of the 2 wires on my vapor stat with the other probe to measure voltage? if its > 120 volts, ill buy a 12 gauge wire with the flex metal conduit with the conduit connector?

EdTheHeaterMan

I hope all you Heating Helpers realize that this guy is all THUMBS Get it... thumbz!

Are you comfortable with this guy doing electrical work.

Jamie Hall

If it's greater than 30 volts, 12 gauge with flex metal conduit.

tumbz

EdTheHeaterMan said:

I hope all you Heating Helpers realize that this guy is all THUMBS Get it... thumbz!

Are you comfortable with this guy doing electrical work.

LOL...

I actually know how to do basic electrical. i installed lights, bathroom fans, added outlets, changed breakers, etc.... this is not my line of profession ( im a nurse ), so i need to be walked through.

ethicalpaul

You don’t need 12 gauge but honestly please hire an hvac tech to wire this for you. 😬

Learn to use the meter yes, but instructions about where to probe your possibly 120v conductors are not best learned on a text forum. I recommend YouTube, there are good educational videos by licensed electricians.

tumbz

Jamie Hall said:

If it's greater than 30 volts, 12 gauge with flex metal conduit.

ty jamie!!!

tumbz

Jamie Hall said:

If it's greater than 30 volts, 12 gauge with flex metal conduit.

Its only 2 volts.  Heres a picture.

So in this case, can i just use the wire i showed above?

tumbz

thats a T STAT wire btw..

Jamie Hall

Before I say yes... can you figure out where, on the burner control, one of the wires from the pressuretrol eventually connects?

tumbz

Jamie Hall said:

Before I say yes... can you figure out where, on the burner control, one of the wires from the pressuretrol eventually connects?

I opened the control box and its a mess of wires...

Jamie Hall

I hate it when people wire things that way... it doesn't have to be.

I have to admit that if I were doing the job, I'd take a length of 12/2 BX and a couple of proper fittings and a wire nut and just wire it up with that and not worry about the voltage... Can't go wrong that way.

tumbz

Jamie Hall said:

I hate it when people wire things that way... it doesn't have to be.

I have to admit that if I were doing the job, I'd take a length of 12/2 BX and a couple of proper fittings and a wire nut and just wire it up with that and not worry about the voltage... Can't go wrong that way.

yea its ugly. LOL. sloppy job. I would fix it if i knew how.

But do you think my T STAT wire is okay to connect my vapor stat to pressuretrol since its only 2 volts???

tumbz

im going to install it as follows on this pic.

Jamie Hall

Honestly, I wouldn't, unless I were absolutely positive that the controls were in a low voltage control circuit and not in the power circuit. And I'm not, since I haven't traced the rest of the circuit. As I said, I'd just bite the bullet, use 12/2 BX and relax.

tumbz

Jamie Hall said:

Honestly, I wouldn't, unless I were absolutely positive that the controls were in a low voltage control circuit and not in the power circuit. And I'm not, since I haven't traced the rest of the circuit. As I said, I'd just bite the bullet, use 12/2 BX and relax.

OK. i will just use the larger gauge wire and connect as pictured. THANK YOU JAMIE!!!

I have some romex wire

ethicalpaul

The Burnham Megasteam uses 18 gauge for its 120v wiring but knock yourself out with the 12gauge!

Nothing should be 2 volts. Did you have the meter on AC? It should be 24v or 120v AC

CLamb

@tumbz In your photos you are measuring the voltage from the terminals of the Pressuretrol to protective ground. What you want to measure is the voltage across the Pressuretrol terminals when the boiler is on but the Pressuretrol is keeping it from running.

tumbz

ethicalpaul said:

The Burnham Megasteam uses 18 gauge for its 120v wiring but knock yourself out with the 12gauge!

Nothing should be 2 volts. Did you have the meter on AC? It should be 24v or 120v AC

THis is the exact wire i have. SInce you said 18 gauge is enough for a 120 volt, can i use this wire?

I bought this from Home depot.

==============================
18/2 Brown Solid CU CL2 Thermostat Wire
by Southwire
#18 AWG Thermostat/Bell wire
==============================

Jamie Hall

It's not the wire size so much as the insulation. If the insulation is rated for line voltage (the rating will be for 600 volts), then yes. Otherwise, I wouldn't unless you are absolutely positive the circuit is a 24 volt circcuit.

ethicalpaul

I’m with @Jamie Hall, it’s the insulation I would doubt with thermostat wire.

Burnham specifies TW type like this:

https://www.kristechwire.com/product/tw-thw/

tumbz

ethicalpaul said:

I’m with @Jamie Hall, it’s the insulation I would doubt with thermostat wire.

Burnham specifies TW type like this:

https://www.kristechwire.com/product/tw-thw/

Ill just use my romex and call it a day.

Also guys, what is this connector called?  Its just a snap on , into the knockouts.  Also the flexible conduit looks like 1/2inch thats connected to this 3/8 connector....  am i correct?  Im ready to buy some.to cover all my wires....