Furnace does not turn on

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1

While the Cooling and Fan functions work as expected, my HestiaPi does not seem to be able to control my furnace.

What happens when the furnace should kick on is the fan immediately turns on but the furnace itself does nothing (with my old analog thermostat, the furnace would kick on for about 15 seconds before the fan turned on).

As a test I re-connected my old analog thermostat and it is still able to turn on the furnace, so it appears the wiring on the furnace end of things is OK.

This is the HVAC version with the Common wire powering the HestiaPi.

Following the instructions here, I got the following voltage readings:

System idle:
C-R:24
C-G:0
C-W:0

Fan on:
C-R:24
C-G:24
C-W:0

Heat on:
C-R:24
C-G:24
C-W:0

I took the unit off the wall and checked the solder points behind the wire screw-down connectors as well as the black relays and all appears good there. Can the issue be something aside from a bad solder point?

Finally, below is some log output from me turning the heat on (set point above current room temp) and then off again. I don’t see anything that looks out of place.

$ openhab-cli showlogs

==> /var/log/openhab2/audit.log <==

==> /var/log/openhab2/events.log <==
2020-10-05 19:44:48.680 [nt.ItemStatePredictedEvent] - MyTempProxy predicted to become 71.0
2020-10-05 19:44:48.777 [ome.event.ItemCommandEvent] - Item 'MyHumiProxy' received command 45.4
2020-10-05 19:44:48.890 [nt.ItemStatePredictedEvent] - MyHumiProxy predicted to become 45.4
2020-10-05 19:44:48.985 [vent.ItemStateChangedEvent] - MyHumiProxy changed from 45.6 to 45.4
2020-10-05 19:44:59.049 [vent.ItemStateChangedEvent] - MyHumi changed from 45.4 to 45.5
2020-10-05 19:44:59.252 [ome.event.ItemCommandEvent] - Item 'MyTempProxy' received command 71.0
2020-10-05 19:44:59.294 [nt.ItemStatePredictedEvent] - MyTempProxy predicted to become 71.0
2020-10-05 19:44:59.335 [ome.event.ItemCommandEvent] - Item 'MyHumiProxy' received command 45.5
2020-10-05 19:44:59.464 [nt.ItemStatePredictedEvent] - MyHumiProxy predicted to become 45.5
2020-10-05 19:44:59.587 [vent.ItemStateChangedEvent] - MyHumiProxy changed from 45.4 to 45.5

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:30:21.263 [INFO ] [lipse.smarthome.model.script.Default] - HeatingPin set to OFF.
2020-10-05 19:30:21.565 [INFO ] [lipse.smarthome.model.script.Default] - Heating2Pin set to OFF.
2020-10-05 19:30:21.972 [INFO ] [lipse.smarthome.model.script.Default] - FanPin set to OFF.
2020-10-05 19:33:36.616 [INFO ] [lipse.smarthome.model.script.Default] - Starting Heating2Timer timer to 0 minutes.
2020-10-05 19:33:37.079 [INFO ] [lipse.smarthome.model.script.Default] - HeatingPin set to ON.
2020-10-05 19:33:38.061 [INFO ] [lipse.smarthome.model.script.Default] - FanPin set to ON.
2020-10-05 19:33:38.361 [INFO ] [lipse.smarthome.model.script.Default] - Heating2Pin set to ON.
2020-10-05 19:33:47.745 [INFO ] [lipse.smarthome.model.script.Default] - HeatingPin set to OFF.
2020-10-05 19:33:48.338 [INFO ] [lipse.smarthome.model.script.Default] - Heating2Pin set to OFF.
2020-10-05 19:33:48.728 [INFO ] [lipse.smarthome.model.script.Default] - FanPin set to OFF.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:10.709 [ome.event.ItemCommandEvent] - Item 'HeatingMode' received command ON
2020-10-05 19:46:10.789 [vent.ItemStateChangedEvent] - HeatingMode changed from OFF to ON
2020-10-05 19:46:11.101 [ome.event.ItemCommandEvent] - Item 'HeatingPin' received command ON
2020-10-05 19:46:11.210 [nt.ItemStatePredictedEvent] - HeatingPin predicted to become ON
2020-10-05 19:46:11.313 [vent.ItemStateChangedEvent] - HeatingPin changed from OFF to ON

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:11.349 [INFO ] [lipse.smarthome.model.script.Default] - Starting Heating2Timer timer to 0 minutes.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:11.642 [ome.event.ItemCommandEvent] - Item 'Pin12' received command ON

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:11.703 [INFO ] [lipse.smarthome.model.script.Default] - HeatingPin set to ON.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:11.855 [ome.event.ItemCommandEvent] - Item 'FanPin' received command ON
2020-10-05 19:46:11.900 [vent.ItemStateChangedEvent] - Pin12 changed from OFF to ON
2020-10-05 19:46:11.931 [ome.event.ItemCommandEvent] - Item 'Heating2Pin' received command ON
2020-10-05 19:46:11.993 [ome.event.ItemCommandEvent] - Item 'MainSwitch' received command ON
2020-10-05 19:46:12.144 [nt.ItemStatePredictedEvent] - FanPin predicted to become ON
2020-10-05 19:46:12.328 [nt.ItemStatePredictedEvent] - Heating2Pin predicted to become ON
2020-10-05 19:46:12.517 [vent.ItemStateChangedEvent] - FanPin changed from OFF to ON
2020-10-05 19:46:12.536 [vent.ItemStateChangedEvent] - Heating2Pin changed from OFF to ON
2020-10-05 19:46:12.633 [ome.event.ItemCommandEvent] - Item 'Pin18' received command ON

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:12.693 [INFO ] [lipse.smarthome.model.script.Default] - FanPin set to ON.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:12.779 [vent.ItemStateChangedEvent] - Pin18 changed from OFF to ON
2020-10-05 19:46:12.919 [ome.event.ItemCommandEvent] - Item 'Pin16' received command ON

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:12.907 [INFO ] [lipse.smarthome.model.script.Default] - Heating2Pin set to ON.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:13.206 [vent.ItemStateChangedEvent] - Pin16 changed from OFF to ON
2020-10-05 19:46:25.074 [ome.event.ItemCommandEvent] - Item 'HeatingMode' received command OFF
2020-10-05 19:46:25.398 [vent.ItemStateChangedEvent] - HeatingMode changed from ON to OFF
2020-10-05 19:46:25.921 [ome.event.ItemCommandEvent] - Item 'HeatingPin' received command OFF
2020-10-05 19:46:25.988 [nt.ItemStatePredictedEvent] - HeatingPin predicted to become OFF
2020-10-05 19:46:26.239 [ome.event.ItemCommandEvent] - Item 'Heating2Pin' received command OFF
2020-10-05 19:46:26.323 [vent.ItemStateChangedEvent] - HeatingPin changed from ON to OFF
2020-10-05 19:46:26.385 [nt.ItemStatePredictedEvent] - Heating2Pin predicted to become OFF
2020-10-05 19:46:26.634 [vent.ItemStateChangedEvent] - Heating2Pin changed from ON to OFF
2020-10-05 19:46:26.828 [ome.event.ItemCommandEvent] - Item 'Pin12' received command OFF

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:26.922 [INFO ] [lipse.smarthome.model.script.Default] - HeatingPin set to OFF.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:27.013 [ome.event.ItemCommandEvent] - Item 'FanPin' received command OFF
2020-10-05 19:46:27.063 [vent.ItemStateChangedEvent] - Pin12 changed from ON to OFF
2020-10-05 19:46:27.157 [nt.ItemStatePredictedEvent] - FanPin predicted to become OFF

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:27.154 [INFO ] [lipse.smarthome.model.script.Default] - Heating2Pin set to OFF.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:27.324 [ome.event.ItemCommandEvent] - Item 'Pin16' received command OFF
2020-10-05 19:46:27.348 [vent.ItemStateChangedEvent] - FanPin changed from ON to OFF
2020-10-05 19:46:27.395 [vent.ItemStateChangedEvent] - Pin16 changed from ON to OFF
2020-10-05 19:46:27.436 [ome.event.ItemCommandEvent] - Item 'Pin18' received command OFF

==> /var/log/openhab2/openhab.log <==
2020-10-05 19:46:27.432 [INFO ] [lipse.smarthome.model.script.Default] - FanPin set to OFF.

==> /var/log/openhab2/events.log <==
2020-10-05 19:46:27.488 [vent.ItemStateChangedEvent] - Pin18 changed from ON to OFF
2

I just started testing mine (home built) and ran into the same issue. Fan worked fine/ AC kicked on fine ///heat (gas) starts but then clicks off and then trys again recursively before I pull the power to the system. Doing this destroyed my image/sd card (oops) during the troubleshooting so I havent had a second chance yet. I just loaded up another image tonight (latest release of One) and will try again tomorrow. Did you try changing heat pin settings to the 4th (unused) relay to troubleshoot if its the relay? (Which I believe is pin 36 | GPIO 16). You don’t have a Carrier furnace by chance?

3

The logs look like the code is doing what it’s asked. The code is set up to make sure the fan turns on before the heat does and turns off after the heat turns off. That could be modified in your case to change that behavior if desired and I can walk you through that when the time comes. But first you need to troubleshoot the relays which I can’t help with.

4

I would vote on the bad solder point on the Pi end from the bottom of the PCB:
Solder instructions.
Pinout

5

That’s a good idea but I couldn’t figure out how do that. A little help please?

You’re right, I should have looked a little closer at the logs. No need to mess with that configuration right now but thank you.

I tried re-flowing the solder on pins 12, 16, 32, 36. Still no voltage across C-W with the heat on. :frowning:

6

Could you measure the DC voltage on those pins and ground (pin6) when the relays should be activated and not activated?
Another idea to avoid changing anything on the software side is to connect the heating to the second-stage heating and change the parameters from the UI to 0 minutes delay and 0 degrees temperature difference. This “should” make second-stage heating work the same way as the primary one but using the other set of pin/solder point and relay.

7

Activated or not, I get 40V across C-6 and W-6

I tried this as well, no change from W in the normal position. 0V C-W in either case

8

Sorry, I meant pins 12, 16, 32, 36 and pin 6.

I meant to connect the heating wire to W2 instead of W. Leave screw terminal W empty.

9

OFF:
6-32: 0.2V
6-16: 0V
6-12: 0V
6-36: 0V

ON:
6-32: 0.2V
6-16: 6.4V
6-12: 6.4V
6-36: 0V

That’s what I did. Probably just did not word my answer very well :slight_smile:

I get 0V C-W with normal heat settings and 0V C-W2 (white connected to W2) when heating in boost mode using the settings you recommended

10

image
image

I swapped 12/16 and used the 4th relay…this solved my issue. So it is either a bad relay or solder joint, more likely solder joint. Your mileage may very. If you are uncomfortable changing settings or connecting to the pi in this manner, I would not recommend it. HestiaPi would be your goto source, they know this stuff alot better :slight_smile:.

11

That is a decent solution especially if you don’t want to (de)solder.

Are you sure your meter is in DC Voltage and not something else? Use the pinout link from above to verify this with 5V pin and 3.3V pin. Your readings should me around 3.3V DC or around 0V (so your 0.2 looks reasonable)

12

Thanks for the info, this is what I needed. I’m actually very comfortable with the software end of things, so this is no big deal to me :+1:

13

You’re right, I goofed that up :grimacing: I measured again and here’s what I’m getting:

OFF:
6-32: 0V
6-16: 0V
6-12: 0V
6-36: 0V

ON:
6-32: 0V
6-16: 3.18V
6-12: 3.18V
6-36: 3.18V

In addition, my furnace actually does kick on when I connect my white wire to W2 and use second stage heating as described in a prior post. When I tested this before I just must not have been waiting long enough for my gas furnace to fire up and get some hot air flowing.

So really the only issue is with Relay 1 or a related solder point. As pointed out by @blase116 I can swap the relays in software, but aside from that what would I do next on the hardware side (aside from yet again re-flowing the solder points)?

14

if you are actually measuring right on the Pi’s male header and not through any solder joint, having 6-32 0V means that this GPIO (the actual broadcom chip pin) is dead somehow which is rather odd unless you may have done something like connecting it to “high” voltage or sorting it to ground while high. In Pi’s terms… 3.9V DC and higher is high enough to kill it. Your measurements though should not add suspicion on the relay 1. No relay would “budge” with 0V as input :slight_smile:
As the Pi is very hard to swap I would go the W2 way and probably simply by using the secondary heating as primary by setting the values I mentioned before to 0.

15

This is exactly what I ended up doing and the heat has been working just fine for me. It’s probably not worth pursuing why I couldn’t get W1 working.

FWIW this is what I was doing.

I can’t rule out the possibility that I broke something. :slight_smile: Thanks to everyone for the help!

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16

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