Need replacement Trane Space Pressure

[incontrol]

This is on Intellipak. The current part # is P592. Kavlico now makes a replacement but it's 8-10 weeks out. Can someone verify it's range and output? What kind of power dies it get from the RTU?

[Allen]

Hi Incontrol,
The transducer uses a 5 volt dc power supply and its output is 0.25 vdc at 0 inches of pressure difference. It puts out 0.75 vdc for every one inch of pressure difference. So at one inch of pressure difference its output is 1 vdc, at two inches it is 1.75 vdc.

The range is 0 to 5 inches of water column.
Is the transducer bad? Or is the Ipak telling you that the sensor has failed?
If the Ipak is saying that the sensor has failed, chances are the sensor is good, it was out of range (voltage output was higher or lower than the Ipak expected) for a period of time. This means that the pressure was higher or lower than expected for that period.

Which pressure transducer is giving you the problem, duct static or space pressure? There is a way to switch them, and they are the same.

Good luck,
Allen

[incontrol]

There are space diagnostics in the history but it does seem to be working ok. We were going to replace them to be on the safe side. I know there was a bulletin about replacing the wire with shielded but this unit was built in 2004 which I believe they fixed the issue after 1994. Bulletin SZ-SB-48. I can't wait 2 months. Is there another replacement?

[Allen]

Hi incontrol,
As far as I know there is no other replacement..
I would not replace them, they are very reliable.
If the space pressure gets too low, because not enough outside air is being brought in to make up for losses, the output voltage will be out of the firmware programmed range generating the ever popular diagnostic "Space Pressure Sensor Failure."
The same thing happens if the space pressure gets too high.
As I said before, the pressure transducers are very reliable.
Something else, was a VFD added to this unit?
If it was, the two pressure transducers should be electrically isolated from from the unit casing. It needs to be mounted on plastic or nylon and the fasteners cannot touch the transducer and the unit metal casing. When the factory began installing VFDs, they used plastic inserts through the unit casing.
Good Luck,
Allen