I've been having mixed results lately when attempting to take over Trane RTUs to run them on the equivalent of a conventional thermostat (Distech ECB-203E, for the curious). These are RTUs with Reliatel controls, so they have RTRM boards with the built-in conventional thermostat interface, meaning a dedicated CTI board isn't necessary. I've read the RTRM manual pretty thoroughly and my understanding is that in order for the RTRM to reference the thermostat terminals, you first have to disconnect the wiring harness to the TCI board as well as the space temperature sensor. Power cycling the board after that should basically force the RTRM to only reference the thermostat terminals for control.
I don't believe I'm missing any other sort of configuration that needs to take place, at least according to the manual I've been referencing. However, my efforts to take over these units have yielded mixed results - some of them have gone completely smoothly with no issues whatsoever, while others (including one I attempted this evening) have resulted in partial or no control of the RTU. In tonight's case, I am able to control the blower but neither stage of cooling, and throwing a jumper onto Y1 or Y2 (and waiting for a good 10 minutes to wait out the delay) doesn't get me anywhere either, so I know it's something internal to the RTRM. Moving the space temp sensor back onto the RTRM allowed the compressor to kick back on almost immediately. I have also taken care to power cycle the RTRM in order to prevent it from attempting to reference the space temp sensor or any network values.
Is there some other sort of configuration switch/jumper I could be missing, or might I be skipping a step? In tonight's case I was suspicious that there was some sort of outside air temperature lockout (was thinking maybe a failed sensor, as the current air temp outside is pushing 100°F), but the fact that the compressor runs just fine on space temperature control makes me think it's something more specific to the thermostat interface. In other cases, I have seen strange behavior such as the blower rapidly short cycling as soon as the space temp sensor is removed from the RTRM, so the symptoms vary a little bit.
I don't believe I'm missing any other sort of configuration that needs to take place, at least according to the manual I've been referencing. However, my efforts to take over these units have yielded mixed results - some of them have gone completely smoothly with no issues whatsoever, while others (including one I attempted this evening) have resulted in partial or no control of the RTU. In tonight's case, I am able to control the blower but neither stage of cooling, and throwing a jumper onto Y1 or Y2 (and waiting for a good 10 minutes to wait out the delay) doesn't get me anywhere either, so I know it's something internal to the RTRM. Moving the space temp sensor back onto the RTRM allowed the compressor to kick back on almost immediately. I have also taken care to power cycle the RTRM in order to prevent it from attempting to reference the space temp sensor or any network values.
Is there some other sort of configuration switch/jumper I could be missing, or might I be skipping a step? In tonight's case I was suspicious that there was some sort of outside air temperature lockout (was thinking maybe a failed sensor, as the current air temp outside is pushing 100°F), but the fact that the compressor runs just fine on space temperature control makes me think it's something more specific to the thermostat interface. In other cases, I have seen strange behavior such as the blower rapidly short cycling as soon as the space temp sensor is removed from the RTRM, so the symptoms vary a little bit.
