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I recently changed our home Wifi router to a Linksys EA9300. The router works great and – together with a RE7000 range extender – provides good coverage in our home.

However soon after we noticed that periodically our phone stopped working. The phone is connected to a Ooma Telo VoIP router. Every day or so the Telo would stop accepting incoming calls and also not provide a dial tone for outgoing calls. The only way to get the Telo working again was to power cycle it.

Looking through the router settings I noticed that the DCHP Lease Time was set to about the same interval (1440 min) at which the phone stopped working. This led to the assumption that there is some action the router takes when DHCP leases expire which brings down the Telo.

The first attempt at a workaround was to assign a static IP address to the Telo. So it should not be affected by the DHCP Lease Time anymore – right ? Wrong. Unfortunately this did not help at all.

The second attempt at a workaround was successful: After setting the DHCP Lease Time to a large interval (129600 min) the problem disappeared and the Telo now reliably stays connected. Of course I fully expect it to lose connection again in 90 days when this interval expires, unless Linksys in the meantime fixes the issue and updates the router firmware.

So here we go. I have a workaround I can live with. I just wish router manufacturers would spend a little more effort in testing their products. It would also be interesting to know how exactly the Linksys router breaks the Telo. The Telo establishes a VPN connection with the Ooma server and I would assume that there is some sort of keep-alive protocol that allows the Telo to detect if the connection is broken, and reestablish it. Clearly that is not happening in this case.

We have a Lennox SLP98V high efficiency furnace that got installed about 3 years ago. This weekend it stopped working – no heat – and the thermostat reported alarm number 276 (Watchguard – Calibration Failure)

The error code indicates that the low pressure switch is not properly closing. This switch makes sure that the combustion air inducer is working properly and drawing exhaust gases out of the combustion chamber.

Somewhat of a giveaway for the source of the problem were the gurgling noises that the furnace was producing while the combustion air inducer was running. Apparently the condensate wasn’t properly draining from the exhaust system.

First I checked the condensate pump that the drain pipe runs into but that seemed to work normally and no water was backed up into the drain pipe. Then I noticed the condensate trap on the right side of the furnace and sure enough it has “Clean Out” written on its lower cylinder – see the picture below.

Once I removed the cap (circled in red) a good amount of water and a bunch of combustion particles came out. Apparently the particles had clogged the condensate trap and water had accumulated in the exhaust system. Since cleaning out the trap the furnace is operating fine again and the gurgling noises are gone too.

Moral of the story – as our equipment gets more complicated we really need to study the user manual well and follow the recommended maintenance procedures.  Lack of maintenance – for example clogged air filters – has always been a frequent reason for service calls to heating contractors but high efficiency furnaces take this to a new level. Not enough to regularly change the air filter anymore.