I have a Heat/AC system with a Buderus Furnace. The heat is delivered by air ducts and the system has two zones controlled by digital thermostats.

Yesterday my first floor heat zone was not turning on automatically, but my upstairs zone was fine. I played around with the downstairs thermostat, but resetting the time zones and changing the batteries did not do the trick.

When I went to the basement I noticed there was a on/off flip switch on the side of the air vent system. It was in the off position and therefore had been in the off position since I have lived in the house. I flipped it to on and all of a sudden the heating system began to work on the first floor?!

I am a heating layperson and don't know much. I am trying to figure out why the switch turned it on and why before yesterday the system always worked with it in the off position. And should I be concerned that I had to switch it to "on"? Do I need to call a professional?

Attached is a picture of the air vent system and the switch.

Any thought

 

I would certainl think the switch should be on. It appears to be power to the air handler. I presume the upstairs system is similar? Check the switch on it. What is that which is strapped to the conduit? It appears to be another wire which goes into the air handler behind the tubing with the foam insulation on it. Please confirm or correct me.

 

Thanks.

The upstairs system is in the attic in a crawl space that I will have to access to check if the switch is on or off.

The wires strapped to the conduit appear to be 1. White - Goes upstairs and likely into the thermostat, 2. Black - Goes into zone handler, 3. Black - Goes into Buderus system.
That is my best gues sin looking at the wires and where they appear to go...

 

I forgot to mention that all three wires do go into the air handler system and then on the other hand they go to the three locations I mentioned in my previous post.

 

Do these wires look like ordinary house wire or are they small diameter thermostat type wire?

 

The two black wires are thinner wires similar to a cell phone charger wire whereas the white wire is a bit thicker....image attached.

 

That all appears to be low voltage wire. It makes perfect sense the white going to the stat. Probably more wires inside the jacket. The browns are probably only 2 or 3 wires each where the white is likely either 4 or 5.

 

Can you offer any thought on why my heat zone/air handler was working with the switch in the off position up until yesterday?
I will likely hire a HVAC person to come take a look and make sure my system is in good shape (since I have not done this in recent years), but trying to understand this situation....
I appreciate the help and insight!

 

I don't think it should have worked. The thermostat should be powered by the air handler. No power to the air handler = no power to the stat = no heat.

 

Thanks! Appreciate the answers back n forth...

Still a mystery, but I better understand it....

Wondering if maybe my cat somehow flipped the switch from on to off?

Anyways, thanks again!

 

It's entirely possible the cat did it. Sometimes they will just bat at things. Ever get a chance to check the other air handler?

 

Might be the cat's work. I have not checked the attic crawl space, but will try to look tomorrow. Access is a challenge so will try to tackle tomorrow. Thanks

 

They make shields to go over switches to prevent accidental operation. Easy to install. Just take out the two cover screws, slip the screws through the holes in the shield, & re-attach the cover.