No signal from boiler

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Moderator: hvxl

No signal from boiler

Postby pieterjm » Mon May 06, 2013 3:55 pm

I bought an assembled opentherm gateway (, the USB version) but sofar I failed in receiving data from the boiler. I tested the gateway with two boilers (remeha quinte and intergas) and three thermostats (two remeha celcia 20 and one honeywell round modulation).

This is my result when following the troubleshooting starting at slave interface (
- After connecting the thermostat to the gateway I see the expected T80190000 messages in the opentherm monitor program
- After connecting the boiler to the gateway does not give the expected result (messages from the boiler).
- The GW=0 command didn't give any data

How to proceed?

Best regards,

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Re: No signal from boiler

Postby hvxl » Sat May 11, 2013 9:06 am

I'm not exactly sure how much testing is done on a pre-assembled gateway. For a self-built one I would suggest to make sure you have the right component values, in this case especially Q1, D9, D10, D11, R1, R2, R3 and R8. Also check the orientation of the diodes D5 through D11 and OK1.

If IC1 is in a socket, try the checks under Opentherm interfaces.

Tests 3, 4, and 5 of the diagnostic firmware may also produce useful data points.
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