RUDD

[appl.tech.29501]

RUDD

Mod# UPKA-030JAZ

Ser# 5345M129612777

Unit appears to be working fine however I feel a problem is upon me.

I noticed several days ago the outside unit was making a buzzing sound (sounded just like a relay on a board) so i tapped on the top of the unit and the buzzing stopped. Later that day same thing... a tap and it stopped. This has been going on for a couple of weeks now and it did not use to do this. The only modification that has been done to the unit recently was I switched from a mercury Tstat to a digital..I think about 2 months ago. I dont see where this would have anything to do with this as it was a simple swap out, but I am by no means a heat/air tech.

Any thoughts?

[ACtechGUY]

I take it this buzzing was going on when the condenser was not running? If so you have 2 possibilities .

• Reversing valve
  Transformer in control box
  

Neither one is a concern. They both tend to buzz when they start to get older. It does not imply impending doom.

[RegUS_PatOff]

Could the digital 'stat (in series) be drawing power from the circuit  ?

Some digital 'stats (in series) use some circuit power and present a voltage drop across it's "electronic switch".

(you could measure)

(unless it uses a Relay, which you would hear)

What model 'stat ?

[appl.tech.29501]

Thats the best news I have heard in a while. Condensor was not running. When it warms up a bit I will pinpoint the buzz.

Thanks alot !!!

[ACtechGUY]

[user=3641]RegUS_PatOff[/user] wrote:

Could the digital stat (in series) be drawing power from the circuit ?

The only problem with that is the buzzing would be at the fancoil and not at the condenser. If there is a transformer in the condenser it would not be powering the thermostat. Therefore not affected by extra load from inside.

UNLESS there is no transformer outside and the extra load on the main transformer is resulting in the revering valve buzzing.(maybe)

[appl.tech.29501]

yall gonna make me go outside aint ya

[ACtechGUY]

I sure wouldn't go outside in the 30's if I didn't have to. :brrr:

[appl.tech.29501]

Took me all day but I finally caught it....its the reversing valve chattering.

Thermostat is a White~Rogers 1F89-211 I believe it has a relay

[ACtechGUY]

I would not be overly concerned. Many things buzz and work just fine for years and years. I would be more concerned about a contactor buzzing.

Just for your info: A reversing valve stays energized while in the heat mode even if there is no call for heat.

I see your new thermostat is powered by the system transformer.It may be putting enough of an added load on your transformer to affect the reversing valve coil, upgrading to a shiny new 75 VA transformer would fix that real good. Worth a shot if you have one laying around.

Then again, it may have no effect at all :?