Bonnet Sensor Search

[pKp]

Howdy - very new here, please excuse my HVAC ignorance.

System is HP+aux furnace under the house. It's a York 4-ton HP outside, with a York Diamond 90 furnace inside. I believe there is a YorkGuard controler, but not entirely sure as it is not labeled on the box. Unit is circa 1999. York T874R1046 t-stat on the wall.

The red Em Heat light is flashing on the t-stat - 9 times. Found that to be a "open bonnet sensor" problem. Also, the HP seems to be locked out - currently running only the aux heat furnace under the house. HP never comes on during heating cycle.:gah:

Now the big question - where is the "bonnet sensor"? Easy to replace? Part number"?

Big thanks!

[jpsmith1cm]

What makes you think that the sensor is defective?

It could be another problem with the system. A Professional can make that determination easily for you.

[beb]

This is time to call a pro. it could be numerous things causing that problem.

[pKp]

For all those who actually use this site to find useful information, rather than pitch professional HVAC business, here's what I've been able to find/do on my own.

The Bonnet Sensor is York part number 37309243000. It is wired into the add-on control panel at S1 an S2. If it's not sending the proper signal to the control box you will get 9 flashes of the Em Heat light on your t-stat.

I found one at the local plumber supply - $. Replaced it - unit now works perfectly.

Again, thanks for the help.:whistle: