Reduce 120v house current to 12v heat recovery ventilator

In summary, the conversation discusses the issue of connecting a new HRV to a 120v line with mechanical timers in three bathrooms. The heating contractor suggests pulling new 12v wiring, but the original electrician believes the brown wire from the relay may already be 12v. It is possible that the metal box marked as a relay also acts as a step down converter. The best way to determine this is with a meter. The question of whether or not new cables need to be run is raised, as the new HRV should be able to be controlled with the existing mains voltage cables.
  • #1
Barrymcduck
1
0
We had a heat recovery ventilator that was controlled by a mechanical timer connected to a 120 v line (the line has its own breaker in the electrical panel and is also connected to a few lights and plugs) in each of three bathrooms. The 120v line is connected to a metal electrical box marked as a relay, that was then connected to the HRV with some thin brown wiring that comes from the relay. We have installed a new HRV and the heating contractor has indicated that he cannot connect the 120v line timers to the new HRV as the connections must be 12v. He wants to pull new 12v wiring from each of the three bathrooms (not a simple or inexpensive project in a two story house).

I am not convinced that the brown wire coming out of the relay is not 12v (the line going in is a thick white cable). Is it possible that the metal box marked by the original electrican as a relay (which would open or close the circut when one of the three timers was activated) also acts as a step down converter as well? Is there any simple way to determine this?

Thanks.
 
Engineering news on Phys.org
  • #2
Barrymcduck said:
Is it possible that the metal box marked by the original electrican as a relay (which would open or close the circut when one of the three timers was activated) also acts as a step down converter as well?
Yes very possible.

Barrymcduck said:
Is there any simple way to determine this?
Thanks.
With a meter. That probably would've been the first thing the electrician did.

I'm not sure why new cables need to be run. I used to install HRV's but don't understand your situation. In my country you wouldn't run new cables for 12v controls if there were existing (now unused) mains voltage cables already installed. the new HRV would be controlled with the same cables the last one was.
 

1. How does a heat recovery ventilator work?

A heat recovery ventilator (HRV) is a mechanical ventilation system that uses a heat exchanger to transfer heat energy between the incoming and outgoing airstreams. In colder climates, the HRV preheats the incoming air with heat from the outgoing air, while in warmer climates, it pre-cools the incoming air. This helps to reduce the energy needed to heat or cool the fresh air being brought into the house.

2. What is the purpose of reducing 120v house current to 12v for a heat recovery ventilator?

The purpose of reducing the voltage from 120v to 12v is to power the fan and control components of the heat recovery ventilator. The fan and controls require a lower voltage to operate and reducing the voltage can also improve energy efficiency.

3. Can I install a heat recovery ventilator myself?

While it is possible to install a heat recovery ventilator yourself, it is recommended to hire a professional for installation. HRVs require precise installation and proper ductwork for optimal performance. A professional will also ensure that the system meets all safety and building code requirements.

4. How often should I replace the filters in my heat recovery ventilator?

The frequency of filter replacement depends on the manufacturer's recommendations and the air quality in your home. In general, it is recommended to check and replace filters every 3-6 months. However, if you have pets or live in an area with high levels of pollutants, more frequent filter replacement may be necessary.

5. Will a heat recovery ventilator reduce my energy bills?

Yes, a heat recovery ventilator can help reduce energy bills by reducing the energy needed to heat or cool the fresh air being brought into the house. It also helps to maintain a more consistent indoor temperature and can reduce the strain on your heating and cooling system.

Similar threads

  • Electrical Engineering
3
Replies
83
Views
3K
  • Electrical Engineering
Replies
5
Views
25K
Replies
13
Views
2K
Back
Top