8 votes
Accepted

Why does hooking voltmeter to two transformers show 0 voltage?

To measure voltage, you need a complete circuit. Connect a voltage meter between a hot 120V wire anywhere in your house and a neutral wire anywhere in your house and you will get 120V because the ...
6 votes

Find replacement HVAC transformer

The single red wire makes no sense. It may be a leftover from a previous configuration - along with a black or white wire that was removed. As far as a replacement, the main consideration is voltage. ...
5 votes

Find replacement HVAC transformer

Any 24 Volt transformer will do. The higher the wattage rating, the better to prevent overload. A wattage should be in the range of 30, 40, 50 watts, and is measured/labelled in VA or W. Do not ...
  • 11.3k
4 votes

Which breaker controls the HVAC unit?

In a rental unit you need permission from the landlord to do any work. Legally the landlord can make claim to any appliance you install on the building. To place a smart thermostat, you need to ...
4 votes

Which breaker controls the HVAC unit?

5/7 is labeled heat, but heat is actually a furnace of some sort which includes an air handler. That air handler is also used by the air conditioning on 2/4. To play it safe, turn both 2/4 and 5/7 off....
4 votes

Why does hooking voltmeter to two transformers show 0 voltage?

Transformers are magnetic devices. There is no electrical connection between the secondaries (the low voltage side), so what you are seeing makes sense.
3 votes

Why does hooking voltmeter to two transformers show 0 voltage?

In a nutshell, the secondary voltage is a result of the field created in the windings around the core of the transformer. If you leave the core, you lose the voltage.
  • 69.2k
1 vote
Accepted

Use one Ecobee thermostat to control three electric baseboard heaters with Aube RC840 relays?

You can have an unlimited number of relays, but only one transformer. (unless you do weird tricks with Rh/Rc). Well, actually there's a practical limit on relays. The Ecobee will only be rated to ...

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