Nest@opentherm
Posted: Fri Dec 05, 2014 11:52 am
Hi,
I'm trying to get my new Nest On/Out thermostat to work together with a Honeywell Modulation thermostat. I figured out that the Nest can give a pulse to a switch that lets go the Opentherm protocol of the Honeywell to my Remeha 28W ECO. [ Honeywell in the "continu" mode, external temperature input on]. However, when Nest stops asking Opentherm by setting the 2 wires to off, Honeywell is loosing its memory and time indication after a while. I therefore need a permanent low voltage input to the Honeywell via Opentherm, without any signal on it. \
QUESTION 1 : What's the optimal voltage [without pulses] of an Opentherm connection.
QUESTION 2 : Does it harm the Honeywell Chronotherm thermostat to provide an external Alternative Current (AC) feed, switching with the real Opentherm connection [ when in operation]
QUESTION 3 : do I somewhre need a condensator during the "off" modus to prevent Opentherm pulses from the Chronotherm to the external AC input. Any idea what pF ?
I'm trying to get my new Nest On/Out thermostat to work together with a Honeywell Modulation thermostat. I figured out that the Nest can give a pulse to a switch that lets go the Opentherm protocol of the Honeywell to my Remeha 28W ECO. [ Honeywell in the "continu" mode, external temperature input on]. However, when Nest stops asking Opentherm by setting the 2 wires to off, Honeywell is loosing its memory and time indication after a while. I therefore need a permanent low voltage input to the Honeywell via Opentherm, without any signal on it. \
QUESTION 1 : What's the optimal voltage [without pulses] of an Opentherm connection.
QUESTION 2 : Does it harm the Honeywell Chronotherm thermostat to provide an external Alternative Current (AC) feed, switching with the real Opentherm connection [ when in operation]
QUESTION 3 : do I somewhre need a condensator during the "off" modus to prevent Opentherm pulses from the Chronotherm to the external AC input. Any idea what pF ?