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Thread: EvoHome ATF600 power supply issue

  1. #1
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    Default EvoHome ATF600 power supply issue

    Hi,

    I recently installed a EvoHome system. The EvoTouch panel is installed on an ATF600 wall mount. As there was no room behind the wall mount, the existing thermostat wire was reused. Because of this the power supply of the ATF600 is installed near my boiler.

    Occasionally i see a error messages in the EvoTouch log saying something like the power supply is bad. They are very concentrated in time. For hours no error, then dozens in a matter of minutes.

    I guess this has something to do with the reused thermostat wire (and its length/resistance).

    Any thought on this?


    Greetings,

    Jack

  2. #2
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    My installation is the same as yours - I removed the old thermostat which had no back box behind it, just wire coming out of the wall, and reused the cable that went to the wiring centre, so I also had to mount the transformer in the wiring centre at the far end of the existing cable.

    Mine has worked OK, however I have occasionally seen a momentary alert about "low mains voltage" when moving the controller around in the cradle, but not when it is just left alone. Another thing I've noticed is that the output of the transformer is significantly lower in voltage than the normal table mount. My table mount puts out 5.0 volts, while the transformer for the ATF600 is only 4.1 volts even without a load, which seems awfully low to me. I don't know if they're all like this or whether mine is faulty. This lower voltage would tend to compound on top of any high cable resistance issue.

    Do you know what the length and gauge of wire is from the base to the transformer ? Although I can't find it with a quick look, I'm pretty sure that the install booklet that came with the wall mount specified the minimum recommended wire gauge for a given length cable. Perhaps someone else can find the recommended minimum wire gauge ?
    Last edited by DBMandrake; 7th November 2018 at 09:16 PM.

  3. #3
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    Hi,

    I agree with your analysis. Mine ATF600 outputs about 4.2 V with the Evotouch connected.
    I suspect that when the recharge cycle of the internal rechargeable batteries kicks in the voltage drops as a result of the resistance of the used wire. That would also explain the non-continuous error messages.

    I measured a resistance of about 1.4 ohms in total (length unknown, estimate ~2x8m). According to the electrical parameters (its in Dutch) a maximum length of 10 m is possible with a wire cross section of 1 mm2. I'm almost sure the cross section of my wire is less.

    I wonder why the table stand has a supply of 5 V? It would make more sense if the ATF600 had a 5V supply and the table stand 4.2V.
    I found a Dutch website which advertises a stronger supply for the ATF600 (https://wifithermostaten.nl/voeding-wandhouder.html) to counter this specific problem. Although they don't specify its characteristics, I'll bet it is a 5V supply.

    Greetings,

    Jack

    Evohome.jpg

  4. #4
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    Why not just use the power supply of the base stand. They were identical in the previous non Wifi version. I remember I hacked off the front of my desk stand to make a wall mount before getting a proper wall mount.

    P.S. Just remembered that in the Wifi model it's no longer a built in psu but a wall plug brick. But the PSU should still be ok to use directly. I too have a similar remote PSU set up and I didn't even use the PSU that came with the newer WIFI wall plate, just used the old one that was already wired up.
    Last edited by bruce_miranda; 14th November 2018 at 10:57 PM.

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