Hi all,
I just had a new Navien NCB-34WDLE boiler installed to replace my 11 year old Ferroli Optimax HE31C unit. The Navien was recommended to me by a trusted gas engineer, and a few hours reading the literature and testimonals confirmed the choice. The unit does seem very solid and well made (although it's a shame that the pressure vessel is positioned at the back - let's hope it holds up for the foreseeable). It's whisper-quiet in operation too and as far as I can tell, it's using about 10-15% less gas as per the meter readings.
I've had an Evohome setup with an Opentherm gateway for just over a year. It worked quite well, even with the old Ferroli (hint - you have to disconnect the built in timeclock before the Ferroli will respond to Opentherm commands). However, it does not work with the Navien. Central heating is controlled fine, but hot water is disabled and cannot be configured from the front panel. The installer spoke to Navien who are investigating the matter but the first impression is that there is an interoperability problem.
I am a little surprised that I appear to be the first person in the UK to try to use a Honeywell Opentherm gateway with a Navien combi (or at least, the first person to complain about it). Still, Navien are investigating the matter and they will report back to the gas engineer with a response over the coming days.
My guess here - this is pure speculation on my part - is that the Navien, when in Opentherm mode, is expecting the Opentherm gateway to send it a command to enable DHW and set the DHW max temp, but the Honeywell gateway is not sending this so the water stays off. I guess the Ferroli did not require this command to be sent, but the Navien does. If this is the case, I guess that Navien will need to issue a firmware update for their controller to add an option permitting the Opentherm DHW to be locally overridden.
I am not sure whose "fault" this is exactly - is it Honeywell's fault for failing to support controlling DHW temp from their Opentherm stats, or Navien's fault for not catering for the scenario where the Opentherm controller is not DHW-aware ? I doubt there is a "right" answer to this one, but it does highlight that the industry sorely needs an Opentherm certification process which is enforced by the regulators.
I just thought I'd post this in case anyone is considering this combination of boiler and controller. I'd be interested to hear if anyone else has heard of this problem. I will report back here with Navien's response.
I just had a new Navien NCB-34WDLE boiler installed to replace my 11 year old Ferroli Optimax HE31C unit. The Navien was recommended to me by a trusted gas engineer, and a few hours reading the literature and testimonals confirmed the choice. The unit does seem very solid and well made (although it's a shame that the pressure vessel is positioned at the back - let's hope it holds up for the foreseeable). It's whisper-quiet in operation too and as far as I can tell, it's using about 10-15% less gas as per the meter readings.
I've had an Evohome setup with an Opentherm gateway for just over a year. It worked quite well, even with the old Ferroli (hint - you have to disconnect the built in timeclock before the Ferroli will respond to Opentherm commands). However, it does not work with the Navien. Central heating is controlled fine, but hot water is disabled and cannot be configured from the front panel. The installer spoke to Navien who are investigating the matter but the first impression is that there is an interoperability problem.
I am a little surprised that I appear to be the first person in the UK to try to use a Honeywell Opentherm gateway with a Navien combi (or at least, the first person to complain about it). Still, Navien are investigating the matter and they will report back to the gas engineer with a response over the coming days.
My guess here - this is pure speculation on my part - is that the Navien, when in Opentherm mode, is expecting the Opentherm gateway to send it a command to enable DHW and set the DHW max temp, but the Honeywell gateway is not sending this so the water stays off. I guess the Ferroli did not require this command to be sent, but the Navien does. If this is the case, I guess that Navien will need to issue a firmware update for their controller to add an option permitting the Opentherm DHW to be locally overridden.
I am not sure whose "fault" this is exactly - is it Honeywell's fault for failing to support controlling DHW temp from their Opentherm stats, or Navien's fault for not catering for the scenario where the Opentherm controller is not DHW-aware ? I doubt there is a "right" answer to this one, but it does highlight that the industry sorely needs an Opentherm certification process which is enforced by the regulators.
I just thought I'd post this in case anyone is considering this combination of boiler and controller. I'd be interested to hear if anyone else has heard of this problem. I will report back here with Navien's response.