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Comment by willvarfar | Hacker News Reader

I guess your toolbox really shapes your solution space thinking; as I read through this, being completely lost in the whole world of RF whatnot, my mind jumped straight to an alternative attack that better fit my own tooling: could you encase the thermostat in a box that you can mechanically control the temperature of?

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I removed the thermistor from inside my wall controller and wired in a digital pot instead. Achieves the same thing without physically heating and cooling the sensor

Or attach an ESP32 to the boiler's control board that closes a dry contact circuit...?

That was my first thought on how I would approach it as well.

The problem is, if your landlord ever comes around for inspection, or the bloody thing breaks down due to your installation attempt, you can be held liable up to and including getting evicted.

Where can you get evicted for something like that? The worst case is that they would sue your insurance for damages, or you'd have to pay them out of pocket.

Many countries have no contest evictions, so you could even get evicted if the landlord doesn't like your cooking.

Probably half of the US, but messing around with stuff like boilers can and will lead to issues even here in Germany.

This sounds good, except that cooling a box is problematic. He needs the temperature sensor to read low so that it turns on the heat.

That said, if he has access to the interior of the thermostat, I'm sure it won't be difficult to replace the temperature sensor with a circuit to cause it to read either really high or really low on demand.

> This sounds good, except that cooling a box is problematic. He needs the temperature sensor to read low so that it turns on the heat.

Ice pack and desiccant?

I was literally imagining duck-taping one of those cheap electric "instant cooling" cups over the box on the wall, and running a small incandescent bulb in to be the heating up element.

For such a minor use case a peltier element is suitable. Very energy inefficiënt but you don't need much and it can both heat and cool.

Yes! You can indeed do exactly this. Look up CoolBot - they do exactly this, by just heating up the existing thermostat

Or, assuming they have physical access to the combi boiler, removing the receiver unit and replacing it with a more Home Assistant friendly combi boiler thermostat.

Probably a 30 minute job if you’ve never done it before and easily reversible with a little bit of double sided sticky tape, which all Brits should be familiar with if they ever made a Tracy Island. There is a real risk of electrocution which could be completely militated against by turning off the power to the boiler.

Still, a fun hack, and nicely executed!

I've heard a story of people renting an apartment with locked thermostat to the legally allowed minimum. Tenants would put ice on the thermostat

I heard that was a well-known trick at my old uni dorm. There was a single thermostat for the whole floor so once people figured out where the sensor was, the ones who lived closest to it would often leave packs of frozen food on it.

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