I sold my previous home 18 months ago. Evohome was installed about 6 years ago ('S' Plan and two BDRs + TRVs +HW kit). Over time, the controller was upgraded and when a new boiler was fitted it was connected to Evohome via an Opentherm Gateway. The original 2 BDRs were left in situ. Clearly, the HW BDR was still connected to the sensor but the CH BDR was disabled. I left it in place as the faceplate was a close by spare if needed.
The clever bit was that the new boiler required what I think Atag calls a modified 'Y' plan or 'W' plan. Rather than go to the expense of changing a lot of pipework, my installer adopted some lateral thinking and he replaced the CH zone valve with a POWER OFF/OPEN inline valve. Whenever there was a demand for HW re-heating, the HW zone valve motored to the OPEN position and the inline valve was wired in series such that it motored CLOSED. Effectively, this gave HW priority and under Evohome control the boiler went to maximum boiler temperature.
Eighteen months on from the sale, the boiler locked out and a heating 'engineer' was called. He diagnosed low system pressure and a failed motor on the inline valve. The latter was replaced. I then receive a cry for help from my buyer as CH appears to be doing its own thing and the old (disconnected) CH BDR is flashing a red light.
After the exchange of a few emails and photos, I think that my buyer has paid for an expensive repair when all that was needed was the topping up of system pressure. I am guessing that the 'engineer' was not aware that there are two types of inline valve and that his training had convinced him that power off means closed. He has fitted a new motor without realising the the inline valve is permanently open for a reason until there is a HW demand, and he has wired the new valve in as if it was a standard 'S' Plan zone valve.
The BDR is flashing because, in desperation, the owner pressed the manual button and there was nothing bound to the BDR.
It does though beg the question: where does an Evohome owner who is not interested in the detail shared on this forum go to get things fixed when the original installer has moved on to other things?
I have suggested that my buyer asks said 'engineer' to give me a call so that I can offer some thoughts on what needs to be done to rectify the situation.
The clever bit was that the new boiler required what I think Atag calls a modified 'Y' plan or 'W' plan. Rather than go to the expense of changing a lot of pipework, my installer adopted some lateral thinking and he replaced the CH zone valve with a POWER OFF/OPEN inline valve. Whenever there was a demand for HW re-heating, the HW zone valve motored to the OPEN position and the inline valve was wired in series such that it motored CLOSED. Effectively, this gave HW priority and under Evohome control the boiler went to maximum boiler temperature.
Eighteen months on from the sale, the boiler locked out and a heating 'engineer' was called. He diagnosed low system pressure and a failed motor on the inline valve. The latter was replaced. I then receive a cry for help from my buyer as CH appears to be doing its own thing and the old (disconnected) CH BDR is flashing a red light.
After the exchange of a few emails and photos, I think that my buyer has paid for an expensive repair when all that was needed was the topping up of system pressure. I am guessing that the 'engineer' was not aware that there are two types of inline valve and that his training had convinced him that power off means closed. He has fitted a new motor without realising the the inline valve is permanently open for a reason until there is a HW demand, and he has wired the new valve in as if it was a standard 'S' Plan zone valve.
The BDR is flashing because, in desperation, the owner pressed the manual button and there was nothing bound to the BDR.
It does though beg the question: where does an Evohome owner who is not interested in the detail shared on this forum go to get things fixed when the original installer has moved on to other things?
I have suggested that my buyer asks said 'engineer' to give me a call so that I can offer some thoughts on what needs to be done to rectify the situation.
Comment