Don’t lose your cool over the DIY smart home

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After two months without aircon, the only thing that stood between my family and a decent night’s sleep was a smart wall switch which insisted on playing dumb – but in the end the switch wasn’t to blame.

This summer we finally decided to replace our dodgy aircon system, which was undersized for the house and has given us nothing but trouble. The new system came with an optional Wi-Fi module, letting me control the aircon from my smartphone, but unfortunately it doesn’t do everything we need.

My aircon is split into two zones; upstairs in the bedrooms and downstairs in the living areas. We only tend to cool one zone at a time, partly to save energy and partly because the old aircon wasn’t powerful enough to do a decent job of cooling both zones on a hot day.

We’ve kept the old ducts and zones but the trouble is that the smartphone app for the new aircon can’t control the zones, they’re controlled by separate wall switches. So I can turn the aircon on and off remotely, but I’m stuck if I want to cool the downstairs zone but the wall switches are set to upstairs. First world problem, I know, but a problem nevertheless.

Get smart

My solution was to replace the two wall switches controlling the zones with two smart wall switches, namely Belkin’s WeMo Smart Light Switch. Technically they’re not designed to do this kind of job, but after talking to Belkin and my aircon guy we decided that the WeMo switches should handle the task – but they couldn’t make any promises.

Unfortunately the aircon installation dragged on and was “one more day” from completion for several weeks. By the end my family was ready to abandon ship, but this week the installation was finally completed.

With the aircon finally up and running, the last simple job was to replace the zone wall switches with the WeMo switches. Except it didn’t go to plan. While the WeMo switches had power, they wouldn’t respond – not even as standard wall switches. Which meant we could run the aircon but not turn on any of the zones, which isn’t very useful

The aircon installer double-checked the wiring and said it was all in order, then left me to sort out the problem over the phone with Belkin’s tech support. Belkin’s people were extremely helpful but we couldn’t solve the problem so I asked an electrician friend to take a look – he wasn’t available until the next day so it was one more long, hot night without aircon even though the system was fully operational.

Crossed wires

To make matters worse, the next morning we had a neighbourhood power outage just before the electrician and his colleague arrived. The power company said it would take all day to fix the problem so I sent them away, but ten minutes later the power was restored so I gave him a call and they rushed back.

At first glance the electricians said the WeMo switches were wired up correctly but, now we had power, closer inspection revealed the neutral wire was not connected. A neutral wire is essential for the WeMo switches and explains why they were misbehaving, if you have an old house without a neutral wire in the wall this is a deal-breaker.

The aircon installer had reassured me he’d wired the WeMo switches correctly, and I wisely wasn’t prepared to pop them off the wall myself and double check.

With the neutral wire connected the WeMo switches started to respond, I could configure them via the WeMo app but when I turned one on it would trip the circuit breaker in the fuse box (the aircon and zone switches are on their own circuit). We thought the problem was with the WeMo switches, but we put back the original wall switch and it still tripped the circuit.

At this point they climbed in the roof to look at the aircon and realised that whoever installed the original system used the wrong coloured wiring and it was a complete mess. Once they rewired the wall switch the aircon zones were up and running.

Switched off

While they were up in the roof, the electricians discovered that the motors which open and close the aircon zones require “two-position” switches rather than simple on/off light switches, which meant the WeMo switches weren’t up to the task. Apparently most aircon zone motors work this way, which means if you’re in this position then an on/off WeMo Smart Light Switch probably isn’t going to solve your problem – but you won’t know until you check your zone controller motors in the roof.

Belkin tells me it doesn’t make WeMo two-position switches so I’m back where I started. There was also a question as to whether the WeMo switches designed for resistive lights would work with an inductive motor. I didn’t get a final answer on that but it became a moot point when we realised we needed two-position switches.

For now the aircon is up and running properly, for the first time since Christmas, although I’ve realised that the Wi-Fi module isn’t responding, so it looks like more fun and games are ahead before I can use the smartphone app.

Do you have a smart home DIY grand plan? What hassles have you run into along the way?