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3 years ago
Thoughts on Y Plan (mid position valve) system
Finally came across a Y plan system.
Any thoughts on how to best control this from Loxone? I know what all the different wires do. My main challenge is the hot water demand (on/off from the HW thermostat).
At the moment, I cannot think of a solution that doesn’t require an additional NC relay. I am hoping there is a more elegant way to do this in config?
Lots of additional complications with existing system, etc but once I nail down the basics, I should be able to incorporate this.
2 Answers
3 years ago
Hi Prem
Hard to offer 100% guidance as there will always be slight variations in system design and wiring as Y plan merely refers to the plumbing and using a Mid position valve. I would recommend removing any form of hot water timers and bringing this within Loxone for standardised control.
I would suggest considering.
1x Loxone Relay for the Boiler Trigger
1x Loxone Relay for the White core of the valve
1x Loxone Relay for the Grey Core of the Valve
Also as the tank thermostat should be a simple relay, then I would consider having this wired as a Digital Input fed from 24VDC so we can detect when the tank is at temperature.
Then assuming the following, the picture attached should cover it in config.
When no power is applied to the valve it will be in the hot water position.
When power applied to white core only it will be hot water and heating.
When power applied to white and grey cores then it will be heating only.
The Tank stat digital input can then be used to reset the schedule within Loxone.
Attachments
3 years ago
I did this today using your suggestion above Hugh. Works well. I added one more AND block for HW demand and no CH demand as there was a second zone valve (2-way) for the HW due to it being an unvented cylinder.
See attached PDF.
Looks messy because of the added complication of utilsing current heating system until each room is decorated and heating replaced with Loxone.
The Pink blocks are temprary and will be removed after all rooms completed.
Attachments
3 years ago Hi Prem, looks good. Another thing you could do is instead of having the schedule for HW and the HW thermostat into an AND block. Invert R on the Schedule and put the HW stat into this. It will still do the same thing, but in the app the customer will see schedule disabled by configuration when the tank is at temperature which gives them a nice visual indication of why the boiler isn’t on.
3 years ago Thanks Hugh.
That’s how I would have normally done it but thje clients just wants to see that hot water is on i.e. selected. Not worried about the boiler, etc.
Still used to seeing the red leds on the traditional time switches. Not sure how they’ll cope with individual room schedules / temperatures??!! Probably blow their minds!!
Thanks Hugh. Was leaning towards the HW thermostat as an in put like you suggest, but with a NC relay for the hot water.
Will try out above method next week and feedback.
Added complications are an additional zone valve for unvented HW cylinder as per regulations. This is an extension to the left and right of a house. Client wishes to retain existing heating system (central thermostat) for most of the house for the foreseeable future. Ancient boiler from the 80s with gravity fed system, external pump, etc. Yes, I know!!