New EmonTH with external temp always reading 0 on the external probe

Getting Started
1

Hi there,

New user here. I’ve just unboxed my Level 3 Heatpump kit and started it up. I’ve bought an extra EmonTH with external probe, which works. But for some reason the external temperature is always 0. Why would this be?

2025-07-28 07:00:27,683 INFO     SPI        Packet received 12 bytes
2025-07-28 07:00:27,683 DEBUG    SPI        9 NEW FRAME : 
2025-07-28 07:00:27,684 DEBUG    SPI        9 Timestamp : 1753682427.683698
2025-07-28 07:00:27,685 DEBUG    SPI        9 From Node : 25
2025-07-28 07:00:27,685 DEBUG    SPI        9    Values : [24.5, 0, 59.7, 3.1, 0]
2025-07-28 07:00:27,686 DEBUG    SPI        9      RSSI : -65
2025-07-28 07:00:27,686 DEBUG    SPI        9 Sent to channel(start)' : ToEmonCMS
2025-07-28 07:00:27,686 DEBUG    SPI        9 Sent to channel(end)' : ToEmonCMS
2025-07-28 07:00:27,924 DEBUG    MQTT       Publishing: emon/emonth2_25/temperature 24.5
2025-07-28 07:00:27,926 DEBUG    MQTT       Publishing: emon/emonth2_25/external temperature 0
2025-07-28 07:00:27,927 DEBUG    MQTT       Publishing: emon/emonth2_25/humidity 59.7
2025-07-28 07:00:27,928 DEBUG    MQTT       Publishing: emon/emonth2_25/battery 3.1
2025-07-28 07:00:27,929 DEBUG    MQTT       Publishing: emon/emonth2_25/pulsecount 0
2025-07-28 07:00:27,930 DEBUG    MQTT       Publishing: emon/emonth2_25/rssi -65

image
image2118×616 47 KB

2

Welcome @rvangraan - can you provide some more information re. how you’ve connected the external sensor? Also, are you able to connect a serial device to see what is happening when you start up the emonTH?

3

hi @awjlogan I received the sensor already connected from the store, so it was done at the store. Here is a photo.

DFE97E00-C527-4172-8744-37F3AC66C8E3
DFE97E00-C527-4172-8744-37F3AC66C8E32268×4032 1.27 MB

I haven’t got a serial connector, waiting for one to be delivered so that I can check if the external sensor is enabled.

1 Like
4

That looks OK to me. You could try slackening the screws and checking that the wire has been stripped back far enough and not clamped onto the insulation, and then take a battery out for a few seconds so that it restarts and has the opportunity to detect the external sensor again.

I don’t know that The Shop checks things like this before it packs and despatches them, but I would be surprised if they didn’t.

5

As @Robert.Wall suggests, we do have a policy of testing units prior to shipping and this should have been checked.

If it is our fault, we should at least reimburse you for the cost of purchasing the serial connector.

2 Likes
6

Hi there, thank you for the quick responses. I’m waiting for the serial adaptor to be delivered and then I’ll have a look and let you know. Thank you!

7

@Gwil quick update. I received my FDDI programmer from the shop over the weekend. The fault turns out to be simple. The “external temperature” setting was still on 0, so I turned that on and it’s now recording data.

1 Like
8

Very sorry about that, that is careless on our part. I have sent you a private message.