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#21220 - 01/29/03 02:55 PM Furnace causing static on TV
minangelo Offline
Junior Member

Registered: 01/29/03
Posts: 9
Loc: Ogunquit, Maine
I have a customer who is getting static on TV reception every time the furnace comes on. My guess is that it is something to do with the motor. Anyone have any one have any suggestions.


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#21221 - 01/29/03 03:05 PM Re: Furnace causing static on TV
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
If its oil fired there is also a high voltage ignition on it also.

Can you verify that is properly grounded?
Bob Badger
Construction & Maintenance Electrician

#21222 - 01/29/03 04:28 PM Re: Furnace causing static on TV
GlennH Offline

Registered: 11/15/01
Posts: 39
Loc: pa.
I think iwire pegged it.

Make sure it is properly grounded first, then maybe have serviceman change ignition transformer on burner. I once had same problem after a few tries with everything else it turned out to be the Honeywell circulator/burner control on heater, bad contact when burner was firing.


#21223 - 01/29/03 07:25 PM Re: Furnace causing static on TV
Electric Eagle Offline

Registered: 04/20/02
Posts: 928
Loc: Alpharetta, GA
Another sugestion if the above don't work.
These are probably on the same phase, so if you move one or the other to another phase, the problem may go away.

#21224 - 01/29/03 07:54 PM Re: Furnace causing static on TV
Trumpy Offline


Registered: 07/05/02
Posts: 8532
Loc: SI,New Zealand
Any sort of bad connection or un-suppressed motor, can play havoc with a TV set.
Placing an adequately sized capacitor across the motor terminals, will nip this in the bud.
Sorry I can't be of more help.
Let's face it, these days if you're not young, you're old - Red Green grin

#21225 - 01/30/03 08:38 PM Re: Furnace causing static on TV
Scott35 Offline

Broom Pusher and

Registered: 10/19/00
Posts: 2724
Loc: Anaheim, CA. USA
This scenario sounds like either the Ignitor (High Voltage Pulses - like an Automotive Ignition System), the Start Switch on the Blower Motor (on split phase Motors), or both, are causing the interference.

These sources will cause a series of pulse-like "streaks" to appear across the CRT along with an audible noise (normally) in the audio portion of the TV Receiver.

The interference could be entering the set from the Antenna line, the AC power circuit, or both.

As stated before, passing the noise to ground via filters will work. Find out where it is entering from, then filter that circuit at the set.

Also, be sure the metallic frame of the furnace is driven to ground (properly grounded). This will assist to shield some of the Capacitive bursts from the Ignitor or Motor.

P.S. If for some reason the Blower Motor is a Brush Type Motor (like a DC Motor), the brushes will create a continuous EMI / RFI situation on the CRT, which worsens as brush-commutator contact also worsens. The results of sparkee brushes will show up on CRTs.
To catch this interference, place a low value capacitor across the Motor's input leads - right at the Motor.

Feel free to ask further questions about this situation.

Scott35 S.E.T.
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!


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