Daikin RTD-20

[CONROD]

Has anyone any experience of operating a Daikin ERQ condenser connected to an AHU via a Daikin RTD-20 interface? The system is cooling only (with separate heater battery), Daikin expansion device with controller. I've wire as per available diagrams - closed run input to S0/S1, 0-10vdc capacity input to S0/S3. The condensing unit will just not start up?? Is there a recommended commissioning step procedure?

[frank]

The RTD 20 needs to operate via Modbus from the BMS.
There are 2 types of control box on the Daikin AHU set up. 1 controls via 0-10v dc input and the other via a digital input leaving the capacity control on the pipe sensors. You should be able to disconnect the RTD and get the system operating by shorting the DI terminals and connecting a PP9 across the 0-10v terminals.

The RTD just allows remote control and adjustment of set points from afar.

Have you connected a BRC controller?

[CONROD]

Hi Frank, how does the RTD communicate with the control box? The only cable connecting the two is the power supply cable? I've a feeling that I've been supplied with the wrong control box which needs a r/c fitted as you suggest. I did connect a r/c and an air thermistor into initially to get it tested and refrigerant charged, but then disconnected these and connected the RTD module - now it don't work the designer says it should run of the 0-10 input as mentioned - Im beggining to think the control box I have is not capable of this. If I do use the brc instead can I switch it on off via the t1/t2 input or will I need a KRP board also??

[Asbolute]

1. Make sure correct capacity plug is connected to indoor control panel
2. Installed BRC (leave RTD offline) and carry out test run operation - outdoor unit/with AHU fan operation
3. Once test run complete, connect RTD-20 with power supply and P1-P2
4. Set ERQ mode - Dip switch 1 & 2 ON
5. Plug the ON/OFF and 0-10V capacity control plug