Networked room thermostats and mains interferance

[flyingsparky]

Hi folks, this is my 1st post and hope this is in the right area.

We went to a site today which had 17 NuHeat networked 15v room thermosats wired in cat5e UTP. We were called in because we wire a lot of Nuheat wet systems and air source, and the installers / previous sparks couldn't get it to work. We spent the afternoon on site and after re-terminating all stats and Optiflo units everything was hunky dory. All stats were visible on the network and the customer was a happy bunny. By the time we had cleared up and drunk coffee it was getting dark and the lights went on. This is a new build with electronic dimmers, transformers and led drivers everywhere. When the lights went on our networked stats all fell off the network, except those on the 1st floor where the lights were all off!
Now, we didn't install the system and have advised that cat5e utp may well be the problem, but, I need some ideas for getting round the problem. We can only tie on and pull through new cables, there is no chance of increasing the existing seperation between mains equipment / wiring / network, and access is non existent. Would shielded help if we tie the shield down to earth? Wireless isn't an option on this particular system.
Any helpful suggestions would be appreciated.
I am a sparks of 25 years + with a business employing 6 near Gatwick and will be happy to help with problems if I can.

Kind regards,


Clive

 

[needasparks]

Would think screened cat5 is the only option from what you say and cant separate the cables enough, In domestic install i always use screened as containment is not an option with routing. I was always told you can run at right angles with power cables but together no more than three metres or eddy takes over and never had a problem yet, same applies to lutron and crestron lighting systems, some digital alarm systems suffer also. May be good to try at least a couple of rooms to see first. good luck.

 

[flyingsparky]

Thanks for the reply Needasparks, The control units, of which there are seven are daisy chained together with a cat5e backbone so I'm going to try replacing those first. Shielded does seem the way to go.

 

[supasparxs]

Hi Clive,
Welcome to the forum.

If you use screened Cat5e cable make sure you earth the screen.
If you don't, the screen acts like an Aerial and it attracts interference

To be honest I wouldn't have expected that the induced Voltage would have caused an issue. But reading your description I would agree with your assessment.

About 9 years ago I was on an install where the block of flats had Lutron Home panels in all flats (artist time they were £5k each) Cat5e as light switches (the lights switches were touchscreen LCD displays and could control the TV, open the curtains, tune the radio, and believe it or not it controlled the lights) there were dedicated radials per light per light fitting so different mood-lighting could be setup.

Though someone else, I maybe able to get hold of one of the commissioning guys on that system.

If you have any real problems let me know.

The companies involve were London based

Richard

 

[supasparxs]

Thanks for the reply Needasparks, The control units, of which there are seven are daisy chained together with a cat5e backbone so I'm going to try replacing those first. Shielded does seem the way to go.

Out of curiosity are the Car5e cables terminated with RJ45 plugs and given an IP address?

If so you could ping the control unit and see the noise build up. This would double check your previous faultfinding

Richard

 

[MarkieSparkie]

Hi, welcome to the forum.

 

[flyingsparky]

Hi Richard, thanks for your input. The cat5 is terminated into the little green plugs that you find on Pcb's. I have asked the client to reboot the system this afternoon, whichight give it time to settle down without any lights being turned on. If it boots up fine it's pretty much guaranteed. I feel a bit sorry for him but hey go.