Question for Carrier techs

[licensed to chill]

Would anyone have any information on troubleshooting the ccn and len bus
on carrier chillers and package units with comfortlink controls? Something in more detail than just flashing leds on the boards. Another tech showed me a sheet once that had various boards with part numbers and it showed either voltage or ohm readings to verify if the drivers in the boards were working.

thanks for any help

[chiller32]

you need the service manual which you can get from Carrier they will sell it to you and I don't thinks its much. It will list all the codes in there.

[gyhooyabat]

Chill,

oddly enough there are not that many different boards for the different machines we make, and the common link to communications between the boards would be the red LED on each board. That LED should be insink with each of the other boards, with the main base board (MBB) being the lead board.

Example of the boards being the same: The MBB for our large RTU's is the same board as for most of the 30 series chillers with comfortLINK. Just is a matter of what software is loaded into it.

The communications or LEN side of the bus runs at a baud of 38,800 while the CCN side is set to run at 9600. You can check these settings from the display that came with the equipment (marquee or navigator).

If you are loosing communications with a given board(s) and the marquee display is in alarm because of it, then perhaps first check any external jacks where a computer could be hooked up. The phone jack is usually the cause for most comm failures on machines that were operating fine before the comm failure.

Can you be more specific on what you might be looking for?

[djken]

Is this what you are looking for??

[licensed to chill]

gyhooyabat,

1st thank you for the reply. I have a 50Z2 series package unit with hydronic heating coil. The actuator for the heating valve plugs into the factory harness and communicates thru the len bus. When i started the unit up i programmed the actuator serial number and performed the commissioning test on the actuator and all worked well for 3 weeks. Now i am showing a A641(Hydronic actuator communication failure) I checked for the obvious problems
but actuator will not communicate. I can plug a navigator into the len bus and view everything so the len bus appears to be working. Local tech support not helping too much. Any ideas?

[licensed to chill]

DJKEN,

thank you very much. That was the sheet i was looking for. You the man!!

[licensed to chill]

Gyhooyabat,
On this unit there is a remote jack at the back of the unit to plug in a laptop or navigator. Per local tech support i remove the jack and capped of the wires but it made no difference. The hydronic actuator will still not communicate.

[gyhooyabat]

Chill,

You could have simply sprayed a little contact cleaner into the phone jack in the rear just to make sure there is no rust building up in the jack. That is a problem we have experieced in some areas, but it is not a great problem and if that was the problem you would have lost comm at the marquee display anyhow.

I checked our hot list to see if there are any new issues with the actuators and do not see any as of this moment. We really have not had problems with the micro-processors in the Belimo Actuators, but it is possible you have a failed actuator. If your unit has power exhaust fans, you could remove one of those actuators and install it on your hydronic heat valve plug. Then re-address the hydronic valve actuator and see if your comm returns. If it does, then you have a failed actuator on the valve. You should disable the power exhaust for the moment so that you do not get another comm fail alarm for the actuator you just removed.

You could also use one of the return air/outside air damper actuators, but the exhaust fan actuators are easier to get to.

Let us know what you find.

[Dallas Duster]

Yeah what did you find????

[licensed to chill]

Moisture in the actuator. No room inside of unit to mount hot water valve or actuator so it has to be mounted outside in the weather. Installed new actuator and rainshield and all is good. Another one of Carrier's great designs.:eek:

[Dallas Duster]

Moisture in the actuator. No room inside of unit to mount hot water valve or actuator so it has to be mounted outside in the weather. Installed new actuator and rainshield and all is good. Another one of Carrier's great designs.:eek:

Hey now that sounds like a bad install.:D