Temp Fluctuations

[Mark Rendulic]

I am having some trouble with my Denver EF200 furnace. It has a Bartlett RTC-1000 control. The temperature readout drops 15 deg. F when the power to the elements comes on. It is very consistent.
I checked to see if the thermocouple extension wire was running close to a coil or high power line, but it is not.
Any ideas?

Thanks!

[Art Freas]

Is this a new behavior? Have you updated the firmware recently? Can you update it? I see this when I start a ramp down on my Bartlett genesis controller.

[Shawn Everette]

Is this a actual temp reduction, or just on the readout? I've had issues before with old elements at high temps sending out signal "interference" on GB sending units.

[Mark Rendulic]

I was having problems with the control not reading the thermocouple correctly. I was getting thermocouple errors so I sent the control back to Bartlett and they repaired it. (it was under warranty. Only 18 months old) While it was there they tested it, and returned it (2 weeks ago). While they had it, they deleted my programs and settings. I don't know where all of the settings were because Denver set them.
Anyway I have been watching it closely because of the previous problems so I do not know if this is a new "bonus" feature or if it has been there all of the time.
I'm thinking shielded thermocouple extension wire perhaps?

[Shawn Everette]

If there's power to the coil and it's "sensing" a temp drop that's not actually occurring, then it could be interference that shielding the wire could fix. If the coil is losing power and there's an actual drop then that won't do anything, then something is probably still wrong with the controller, but that could just possibly be changing a parameter that determines how fast it reacts to a temperature drop.

[Mark Rendulic]

The readout drops 15 deg. almost instantly when the power comes on. Then it rises instantly when the power shuts off. This can't be actual temperature. It has to be misreading the thermocouple.

Does anybody have a source for shielded thermocouple extension wire?

[Shawn Everette]

The stuff wet dog uses is supposed to be shielded. You using type R? Alternatively you can try flexible conduit.

[Mark Rendulic]

Yes it is an R Type.
It is in flex up to the control box, but it is not in flex inside the box. I think that is where it is picking up the noise as it passes by the mercury switches.