Honeywell Chronotherm Modulation

This Forum is about the Opentherm gateway (OTG) from Schelte

Moderator: hvxl

Honeywell Chronotherm Modulation

Postby YogiBear75NL » Mon May 27, 2019 10:01 pm

Hello all,

I have the OTGW and a Honeywell Chronotherm Modulation.
OpenTherm firmware OpenTherm Gateway 4.2.5
It's working fine in Home Assistant using an ESP32 with Ser2Net.
I can set the Control Point and read all variables necessary.

But...the time on the Honeywell Chronotherm Modylation is not correct anymore.
It's slowly getting ahead of time. If I don't enable/have the OTGW in between, the time is correct. Well maybe a 5 seconds difference in a week.
But now during a day it's 1 hour ahead of time.

Is this a known issue? What can I do to prevent this as I want to use the Program on the Thermostat.

Starting Member
Starting Member
Posts: 3
Joined: December 2015

Re: Honeywell Chronotherm Modulation

Postby hvxl » Fri Jun 14, 2019 10:15 am

This is not an issue known to me. When I was using the Honeywell Chronotherm Modulation myself, the time was accurate to the second. But I have to admit that was because I kept the OTGW informed of the correct time by sending it SC commands every minute. It would then relay that information to the thermostat.

So it is possible for the OTGW to influence the clock of this thermostat type. But it shouldn't do that unless it is told to do so via SC commands. Otherwise it should behave no different than a boiler would.

1 hour in a day translates to 2.5 minutes per hour. Can you collect a log from otmonitor for one hour that shows this problem? Then I will have a look to see if I can spot what may be causing it.
Senior Member
Senior Member
Posts: 1333
Joined: June 2010

Return to Opentherm Gateway Forum

Who is online

Users browsing this forum: No registered users and 1 guest