Carrier CCN Control

[troymedhurst]

Hi,
Im after some advice on the cotrol philosophy on the ccn network.
I have 2 x 30gh145 units both with CCN-OFF-LOCAL ON switches. One unit is the master with the flotronic master controller with an extra CCN-OFF switch. Found that the switch CCN/LOCAL was faulty and replaced with the switch connected to the master cotroller. According to the manual the switch works on resistence, 0 - 1,962ohmns for enable, >168,250ohmns for stop and 11,396 to 43,254ohmns for disable. So I put a 1ohm resister across terminals for an enable signal, but all i can see is CCN off. The bms signal is a 24v signal to the master controller and this is ok, I cant understand why I am not seeing a CCN on display. We have same set up elsewhere on site and have cross referenced with them. allseems the same. I do not know how the ccn decides what comes on and when, so any insight greatly appreciated. sorry for the long post.:confused:

[Gibbo]

It sounds like you have a Flotronic System Manager module controlling 2 chillers, I'm afraid your going to need a Carrier engineer with a laptop to look at the Flotronic System Manager to see what is holding the chillers off.
Ring Carrier Service on 02088147600 and book a visit.

G.

[james10]

have you got the control signal wired into terminals 31-32 with good conections

[Gibbo]

I think you may have your terminals wrong James, chiller control terminals are 32 and 33.
FSM control terminals are 25 and 26 on the FSM
FSM on/ off switch are 20 and 21 on the FSM

Try putting a jumper across terminals 20 and 21 on the FSM and remove your CCN switch wiring also power off/on FSM and then see what happens wait 5/10 minutes and see.
If still no joy then you'll have to call out Carrier Service at the number i gave you.

[james10]

I think you may have your terminals wrong James, chiller control terminals are .
you'd be right:o

[troymedhurst]

Youre right terminals 14&15 were the ones with the faulty switch so I replaced with the switch that was connected to 20&21. I put a 1 ohm resistor accross 20&21, as i read that 0-1,96ohms gives CCN on.
I also checked the input to 25 and 26 and these are ok. I have since read on another manual that enable is looking for 1.2-1.8kohm, so until I can get a new switch I will try installing a resistor inbetween the 1.2&1.8k ohms.
I will also try powering down and back up.
Thanks for all your input and I will update monday.

[troymedhurst]

Hi just and update.
Tried a 2k resistor -no good!
I will have to phone carrier, if the client gets fed up with it being on local control.

Oh how I hate to be beaten!:mad:

Thanks again for the replies.

[oldschooleng]

i have had this problem,it looks to be the switch thats faulty,but it turned out to be a hidden 2 Amp car type fuse on the main board behind the keypad.it may be the same for you as everting looks to be powered up even with a blown fuse