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Furnace causing static on TV #21220
01/29/03 05:55 PM
01/29/03 05:55 PM
minangelo  Offline OP
Junior Member
Joined: Jan 2003
Posts: 9
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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Re: Furnace causing static on TV #21221
01/29/03 06:05 PM
01/29/03 06:05 PM
iwire  Offline
Joined: Jan 2003
Posts: 4,391
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
Re: Furnace causing static on TV #21222
01/29/03 07:28 PM
01/29/03 07:28 PM
GlennH  Offline
Joined: Nov 2001
Posts: 40
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.


Re: Furnace causing static on TV #21223
01/29/03 10:25 PM
01/29/03 10:25 PM
Electric Eagle  Offline
Joined: Apr 2002
Posts: 914
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.

Re: Furnace causing static on TV #21224
01/29/03 10:54 PM
01/29/03 10:54 PM
Trumpy  Offline

Joined: Jul 2002
Posts: 8,231
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.

Re: Furnace causing static on TV #21225
01/30/03 11:38 PM
01/30/03 11:38 PM
Scott35  Offline

Broom Pusher and
Joined: Oct 2000
Posts: 2,708
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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