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I am connecting an electric air cleaner to my 240v heat pump furnace. Where to I connect the wires to the Siemens 240v to 120v step down transformer Cat. MT0050M series 2 50va

I know to connect the 240v wires to H1 & H2...and I know to connect the 120v wires to X4 & X3...Am I going to use the transformer in series or parallel...when I connect the 240v wires to the transformer and when I connect the 120v wires to the transfer...Further, will the X3 connects be my com/nev. wire when I connect it to the 120v outlet for my air cleaner...I hope this makes since to someone...there were no instruction in my trasformer box.

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You are bucking voltage down to 120 volt from 240 volt using a transformer.
You are connecting one hot leg of 240 volt to H1 and one hot leg to H2.
Suggest you add jumper wire from H1 to H3, and another jumper from H4 to H2. This will give power to primary coil.

You are connecting 120 volt to X4 and X3.
Suggest you add jumper wire from X1 to X3, and another jumper from X4 to X2. This will give you 120V from the secondary coil.

See same instructions on following link:


Water Heater Timers Save Money

Posted on Nov 24, 2014

Testimonial: "Thank you Mr. Haynes...that tells me how to connect the transformer...But what do I do a bout at Nev. wire...there is not one to the furnace, and I will need one for the electric air filter...If I must run a nev. wire from main panelboard. Is there some reason I must take power from the furnace...I am using the com wire from the blower to active the #51 Relay. which tell the air filter to come on and off the same times as the fan. If I am going to run a nev. wire to the air cleaner, why not just run a new 120v circuit to the air cleaner and still let the #51 relay turn the air cleaner on the air cleaner using the com wire from the fan to operate the there some reason I MUST get the power from the 240v furnace, if I'm using the common wire from the fan to operate the relay...thanks again"

  • Gene Haynes Nov 25, 2014

    The transformer will produce the Hot and Neutral needed for 120 volt. Connect your black and wite wires to X4 and X3. Keep in mind that the MT0050M transformer only produces 50 watts (like for a 50 watt light bulb). You can also make 120 volts by tapping into one leg on the 240 Volt line. Then grab neutral wire from any nearby light or outlet box.



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SOURCE: wiring connections for Kichler 900w transformer

You need to connect one wire from each cable to one of the com terminals. The other wire from each cable has to connect to a tap terminal. The tap terminal you use will depend how many lights and the length of the cable. For short cable runs like 25' use tap 1 50' tap 2 100' tap 3 more than 100' tap 4. you may need to connect all three cables to the same tap terminal. If you turn it on and one string of lights is dimmer than the others move the tap connection from that wire to a higher number. The tap terminals send out a little higher voltage the higher the tap number. The obect is to get the same light output of each light compensating for the voltage drop of the cable. This is a lot of info so I hope this answers your question. If you need more help let me know.

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SOURCE: I have a 300 watt Malibu transformer to run 4 step

Take one cable to the x-former to the 4 sets, then Splice all the wires (5 in one nut and 5 in the other) together. Then connect the one set at the x-former. Don't worry too much about the 10 ft issue. It will work fine.

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SOURCE: Intermatic T103 timer wired for 240V

yes u will, but u will have to make sure one of the motor wires are hooked up that way also, in case it has been moved, here is a link with the diagram u need

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SOURCE: How to wire to attic fan?

OK, your new switch will require the use of a neutral wire. So you will have to do what is called a pigtail. You will have to twist another white wire in with your other white wires to attach your neutrals to your switch. Note: white wires are called neutral not common. Hook the wires that were originally hooked up to your LINE to your HOT (Black) on your new timer, and the what was originally LOAD up to the new timer LOAD. SO as far as wiring all that will change is your white wires that need to attach to your timer NEUTRAL.

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SOURCE: Can you please provide instructions

What you are describing is a wall electrical box for a "Wwitch Loop". What this means is that the power source (Hot and Neutral) go to the light first. What the electrician has done is run a wire from the light in which one wire is the hot leg from the source and the other one is the "switched leg" which runs back to the light as controled on-off power to it. The only legitimate way to use this timer would be to replace the wire from the wall switch to the light with a 3 conductor cable (3 current carrying wires and a bare ground or green wire). This would allow you to bring the hot and neutral along with the controlled "switched leg" as this time requires a constant source of power for the timer itself. Don't be tempted to let someone tell you to use the ground wire as a neutral. It is not safe to do that.

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I have a air handler TWE030c14 furnace with amana heat pump, and i want to install humidifier , where do i take my 120 or 24 volts to ryn my humidifier?

My first thought is, if you have to ask this question, you should not be playing with your HVAC because you will likely hurt yourself. But if you insist; What does the humidifier require 120 or 24V? If it is 24V, then you take it after the thermostat at the relay that turns on the rest of the system. If the humidifier wants 120V, take it from the switched portion of the above mentioned relay. Your heat pump is 240V, so one side of the humidifier goes to the relay, the other side goes to ground, not the other side of the 240V return. If your heat pump is connected through a GFI, this will likely trip the GFI, shutting down your heat pump.
Go download

Go to page 12. 24V should be terminal 6 and A on the relay. 120V should be between B and ground on the fan motor. Before opening anything, turn all the breakers to the heat pump, likely 3 dual gang breakers. Have a couple spare automotive ATO 5A fuzes in case you blow one. Have an shut-off valve for the water supply. Please be careful!!! What you are doing has a high potential of hurting yourself or blowing up something in your heat pump, leaving you without heat.

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Hullo guys, i recently purchased a shaving machine with a power adapter that can operate at a voltage of 120V Ac and frequency of 60 Hz. Now unfortunately here in Kampala, Uganda our Op. Voltages and...

You need a step down AC transformer 240V to 120V then you can connect the shaver to the 120V outlet. You do not need to worry about the frequency.

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Just purchased a Filtrete 3M-50 Wifi Programmable Thermostat. I have a Carrier Crusader furnace. I need to connect the Blue wire in the furnace to a terminal so I get power to Wifi module in thermostat....

You'll need the manual for this and electrical knowledge. The Blue wire is the common wire that is needed to supply the 28 volts to the thermostat. The problem and potentially life threatening hazard, is the 28v is off a 120 or 240v transformer and, without proper understanding of electrical diagrams as well as ensuring all power is off the the unit, you can connect to the wrong terminal and burn your house down or electrocute yourself.

I Highly recommend hiring a professional to install that wire. If you insist, I will need the exact model number of the furnace to get the proper manual to help further.

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240v circuit to 120v pool pump

Listen - you had three wires feeding your old 240 volt pump. Two were hot and one was a ground. To run your new 120 volt motor just connect one of the two hots to the motor along with the ground. Cap off the remaining hot wire so nada bad happens and you are good to go.

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I have an intermatic C8865 timer. i want to wire it into an EFM model AF150-1 coal stoker furnace, because the fire goes down to far inbetween actual times heat is called for. also have main switch for...

Intermatic C8865 timer is a 5-hour cycle timer that repeats same cycle each 5 hour period.
This timer has 120Volt clock motor and is 120V timer.
Timer has NO and NC terminals.
NO terminal turns ON when timer turns ON
NC terminals is ON all the time, except when timer turns ON. At this point NC terminal turns OFF.

You have 3 things: 120V timer, 120V honeywell transformer, 120V stoker motor/fan
The transformer needs to be ON at all times.
The stoker motor is going to turn ON when the cycle timer turns ON.

You have 120V cable with black wire, white wire (and bare ground, which connects to green ground screw and to other bare grounds and won't be discussed further)

Black wire is hot
White wire is neutral

Black wire connects to 'Switch common terminal' on timer.
Same wire also connects to black wire on Honeywell transformer.

White wire connects to 'Clock terminal' on timer
Same wire connects to white wire on Honeywell transformer and to white wire on Stoker motor.
So all the white wires are connected together.

Last wire is black wire to stoker motor.
This wire connects to NO terminals on timer.

Here is drawing.
Add a comment any time

Dec 13, 2010 | Intermatic C8865 Timer, 1HR CYCLE TIME, 30...

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How to set a NOMA HTM311A thermostat

Go to the furnace, and see what the black is connected to. If it is not the Y terminal, disconnect it from the Y terminal at the thermostat. While you have the furnace open, check for a blown fuse inline to the transformer or on the control board. If the black was connected to the common or the transformer, and you connected it to the Y, and turned the thermostat to cool, you would have a direct short across the transformer output. You can use a black wire to control the A/C, but both ends need to be connected to a Y terminal.

If you still remember the where the 4 wires were connected to the White Roger thermostat, take note of the name of the terminals the 4 wires are connected to. That may help as sometime the colour of the wires are not always correct.

Or you really want to test it out:
connect RED wire to GREEN wire should turn on the fan
connect RED wire to WHITE wire should turn on the heat

Did you disconnect the power at the furnace first? Maybe you blew a low voltage fuse.

Make sure you increase the heat setting to go above the room temperature.
Thermostat wire color codes explained.
Please note. Not all installers use the proper color codes when they install or replace equipment. It may be necessary go go to the furnace or outdoor unit to verify what wires are for what purpose. Also be sure there are no splices in the wire that could change the wire colors between components.

R (red) or Rh (Red heat) 24 volts from equipment.
Rc (Red cooling) 24 volts from transformer in cooling equipment.
Note: If only furnace has a transformer and cooling equipment does not jumper Rc and Rh.
W (White) sends 24 volts to furnace control to start the heating cycle.
W2 (no standardized wire color, usually whatever wire color is available) controls second stage heat.
Note: W2 is most often used for heat pumps to control what is called emegency heat or Auxillary heat, and most often will use the white wire.
Y (yellow) often (blue) is used, controls cooling unit (outdoor condensing unit) also is used for heat pump heat.
Y2 (no standardized wire color, usually whatever wire color is available) controls second stage cooling.
G (Green) controls the fan "on" operation of the furnace/air handler. Also often is used to start the blower for many electric furnaces.
C (common) most often brown but can also be black or other color available to installer.
O (orange) Energizes heat pump reversing valve for cooling (Trane and most other brands).
B (Blue) Energizes heat pump reversing valve for heating (Rheem, Ruud and Weatherking).

Hope it helps.

Thanks for using fixya.....

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1 Answer

How do I wire an intermatic t-103 timer switch

The T-103 has a 120Volt clock motor

From there, the wiring can go two directions depending on your Load voltage (load is the fan, light or motor that timer turns on-off)

Here is a link that shows exact wiring:

When wiring the T-103, steps 1-2-3 are true for 120V or 240V installation:
1) A white Neutral wire is always connected to terminal A (Neutral wire connects to Neutral busbar in breaker box)
2) A black Hot wire is always connected to terminal 1 >> this hot wire can come from 120V or 240V breaker
3) Black wire going to Load (fan, light, motor) is always connected to terminal 2
The following step is true for 120V Load
4) if Load is 120V, then white wire from Load connects to terminal A
The following steps are true for 240V Load
5) Only the neutral wire connects to terminal A as described in (1
6) The second Black hot from breaker box (240V has 2 hot wires) connects to terminal 3
7) The second White going to Load connects to terminal 4

Here are 2 more links that show how 120V and 240V circuits are wired

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2 Answers

I have a question, why there are 2 voltage in American market? where uses 110v, and where uses 250v? We are a manufacturer of power cords , power supply cords, we really want to know the difference ....

110V is our common household current and 220v is used where heavier voltage is needed, like ovens, stoves, clothes dryers, air conditioners, electric water heaters, arch welders, etc.

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1 Answer

I have a Honeywell H220a humidistat and have everything hooked up, but I cannot get the wiring to work. The wiring diagrams do not include the selanoid that comes with the humidistat. Any suggestions. The...

Thanks for your question Mike,
The wiring for your humidistat and solenoid are fairly simple, you will need 24volt t-stat wire, you have the two wires at the Solenoid, one wire goes to the terminal board at the furnace, it connects to the (c) or common terminal, the other wire connects to one leg of the humidistat, run another wire from the other leg of the humidistat, to either the HUM terminal on your furnace circuit board, make sure its not a 120v leg, should say in the owners manual, if if is or your not sure, connect that same leg to the (w) terminal at the furnace, this way it only comes on in heating mode, some models need a second 120v-24v transformer, but you would still wire it through the same way, only exception is that you have to hook up 120v to the transformer, and route your wiring like I told you above but through the transformer to complete the circuit, hope that helped you out Mike, please let us know, thanks again, mr.grzz

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I have an Intertherm heat pump model number E1EH-010HA. Last night we had a bad storm and our electricity went out and we had a water leak, now out heat pump isn't working. There is power to the...

Your furnace will either have circuit breakers or fuses at the bottom in the panel below the blower. Also, there MAY be fuses in the disconnect box outside that gives power to the heatpump. Intertherm furnaces are famous for leaking water onto the left side of the electrical panel in the furnace which is also convieniently where the low voltage transformer is located. If you consider yourself electrically competent, check to see that you are getting 240v to your transformer and if you are the check to see if you are getting 24v out of the transformer. If you can't find the problem in any of these steps, I would recommend contacting a qualified professional to check the system out.

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