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Jesse

Losing network connection when HVAC cycles on....

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Jesse

Hello and thanks,

 

I think a diagram of your LAN might be in order.

 

I'm also not completely clear on just which devices you had on UPS, at which times. Have you, for example, done a test where everything is on UPS at the same time. Have you done a test where everything is running on UPS (i.e. not connected to AC) while you force the HVAC to come on. If everything is running disconnected from AC, and the problem still exists, then it's not noise on the AC lines.

 

If your LAN cabling is done properly, EMI should not be an issue. Do you have a LAN tester, preferably something that does more than just a wire map check?

 

I moved everything (modem, router, switch) to UPS pretty early on.  As per your suggestion I pulled the plugs on the UPS's and then forced the AC to cycle on (modem, router and switch all on battery power only).  I had a browser open on my wifes machine and was able to fire up and watch a few short youtube videos with no loss of connectivity.  I ran this way for about 4 minutes or so with no problem at all.

 

I have this lan tester: http://www.amazon.com/TRENDnet-Cable-Tester-COAX-TC-NT2/dp/B0000AZK08/ref=sr_1_1?ie=UTF8&qid=1374716592&sr=8-1&keywords=tc-nt2

 

Pretty sure it is just wire map check.  What tester would you suggest?

 

Are you losing connection to your home network or the internet?

Doe this happen every time the HVAC comes on?

 

When this happens my wife loses the ability to access files on our local servers.  Wireless devices sometimes loose connectivity as well.  Thinking about it, I cannot say for sure whether or not the modem is going down, but the router is certainly being affected. I suppose I would need to take the router out of the loop, and plug her laptop straight into the modem, to find out if the modem is being affected as well.

 

No, it does not happen every time the HVAC comes on.

 

Good question. I took it, since he specifically mentioned DSL twice, to mean he means internet connectivity.

 

I also forget to ask another question: does this happen to every computer in the house, or just his wife's? It might be worthwhile to start up every computer in the house and start a continuous PING to a very reliable site (one that normally does not give timeouts) and cycle the HVAC -- see if any, and how many, of the computers show timeouts in the PINGs.

 

I can confirm that it has happened to at least two other computers besides my wife's as well as on at least three of our wireless devices.

 

This might sound crazy, but you don't have a wireless or wifi enabled thermostat by chance? I do have a wireless audio/video transmitter that on one of it's few selectable channels will crash my wireless modem.

I should clarify, the wireless audio/video transmitter is 2.4ghz with its own receiver. It's not trying to connect to my network at all, but it will kill it requiring the router to be power cycled. I never let it sit long enough to see if it would correct itself.

 

Nothing sounds crazy at this point, but no, no wireless thermostats or A/V transmitters.

 

If it is the internet, I would disconnect the cable modem from the home network and connect a pc directly to the cable modem. If the problem goes away, it is your home network, if the problem remains it is an issue with the service.

 

This would be an interesting test.  I will need to run some cable, but it would not be hard to rig something up just to test. 

 

Jesse

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ikon

That TrendNet does look like a basic wire map checker. At that price it would pretty well have to be. Proper LAN testers are hundreds to thousands of $ -- probably not something you're going to buy :)

 

I would double-check all the cabling just to be sure it's all OK. I would also try disconnecting every cable except the ones to the internet and your wife's computer: see if limiting the number of connections makes a difference.

 

If you have, or can borrow, a real Ethernet switch, I would connect your server and hardwired client computers to it and see what happens.

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KydDynoMyte

I think we have overlooked the most obvious answer. You might just have an upset tech savvy ghost on your hands. When the HVAC cycles on do your lights dim?

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ikon

LMAO. :D :D  Why on Earth didn't I think of that?

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Jesse

That TrendNet does look like a basic wire map checker. At that price it would pretty well have to be. Proper LAN testers are hundreds to thousands of $ -- probably not something you're going to buy :)

 

I would double-check all the cabling just to be sure it's all OK. I would also try disconnecting every cable except the ones to the internet and your wife's computer: see if limiting the number of connections makes a difference.

 

If you have, or can borrow, a real Ethernet switch, I would connect your server and hardwired client computers to it and see what happens.

 

I am going to try putting her directly on the modem (i.e. no router, no switch, no home terminated cables).  If that works I will check cables and expand outwards from there.

 

What exactly do you mean by a "real" Ethernet switch?  I have an SMC 8524.  It is a 24 port unmanaged switch.

 

I think we have overlooked the most obvious answer. You might just have an upset tech savvy ghost on your hands. When the HVAC cycles on do your lights dim?

 

It is pretty clear we do have a ghost in the machine.

 

The wife reports that the lights sometimes dim when the HVAC cycles. 

 

Thanks,

 

Jesse

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pcdoc

Assuming that you have UPS on all switches, routers, etc, you mentioned that the HVAC is close to the switch that handles the home run.  I assume this has been UPS'd as well?  How close is the switch?  Might a bit of work, but possible is it to use cord extenders and move the switch temporarily at least 15-30 feet?  I agree it with your friends theory is that you are getting noise from the motor/compressor in your AC but you need to determine if it is EMI or being feed directly into the wiring.  If moving physically away resolves it, it most likely is EMI, if not it is being feed through the lines.  With the right equipment a "good" electrician could possibly measure what is going on the wiring system or EMI.  I am guessing you will need some type of electrical isolation on your HVAC.  If it is EMI you will be able to do a work around however I would still have it check as that level of EMI is dangerous in the long run.  Try moving that switch as far as you can and see what happens.

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KydDynoMyte

...

 

It is pretty clear we do have a ghost in the machine.

 

The wife reports that the lights sometimes dim when the HVAC cycles. 

 

Thanks,

 

Jesse

Lights sometimes dim and network sometimes goes down. Wonder if both happen together. How long does it take to come back online by itself? Does the network come back up by itself while the HVAC is still running or only after it stops?

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ikon

This is beginning to sound more and more like a problem with the HVAC itself. Perhaps the motor is faulty and taking a lot more current to start up than it should. If it's AC, it could be the compressor. Your lights should not dim from the HVAC coming on; something's wrong there.

 

I don't recall you mentioning the SMC before. This is why I mentioned a LAN diagram, so we can see exactly how everything is inter-connected.

 

The SMC should be fine as a switch. The only thing to be sure of is that all of your devices plug into the SMC, not each other. For example, there should be only one Ethernet cable plugged into the LAN ports of your router -- the one that connects it to your switch.

 

Also, when doing your tests without AC power, every device should be on UPS only, including the SMC. Any one device left on AC could mess up the test. If you still have problems with everything disconnected from AC, then I think EMI may be an issue for you. However, like I said in the 1st paragraph, I think that could well be something wrong with the HVAC.

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pcdoc

No doubt there is an issue but I have seen my lights dim a bit sometimes when the AC comes on the summer but I have all the hardware on UPS's which is why I asked the question earlier.  It is either noise coming through the lines in which case a good UPS should condition that out, or it is inductively getting in the network wiring.

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ikon

Interestingly, if the cabling is done properly, signal induction should not be an issue: induced noise should get filtered out by the twisted-pair circuitry.

 

But that does make me think of 1 thing: the OP says he's pulled a bunch of CAT6 cable, in addition to CAT5e. CAT6 is much more sensitive to incorrect installation than CAT5e, and that TrendNet cable tester he's got is no way near sophisticated enough to test CAT6 cabling properly.

 

I'm going to suggest he replace the CAT6 cabling with CAT5e; that, or get a proper tester that can handle CAT6 (not a cheap option). Byte Bros. does make what I consider to be a reasonably priced tester: the Real World Certifier. It's $600, but that's cheap compared to most testers.

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