MrPotts Posted September 14 Share Posted September 14 For energy efficiency is it a good setup to have PDHW when my system boiler can only run at a single flow temperature. The system at the moment is an Splan. Thanks Link to comment Share on other sites More sharing options...
JohnMo Posted September 14 Share Posted September 14 If your boiler only does a single flow temp no advantage over S plan. Most boilers will have options or optional kit that will allow weather compensation. If you add this you can then adapt to PDHW. This basically switch WC off when doing DHW. You would need to share info on your boiler make model or have a read through the manual Link to comment Share on other sites More sharing options...
MrPotts Posted September 15 Author Share Posted September 15 13 hours ago, JohnMo said: If your boiler only does a single flow temp no advantage over S plan. Most boilers will have options or optional kit that will allow weather compensation. If you add this you can then adapt to PDHW. This basically switch WC off when doing DHW. You would need to share info on your boiler make model or have a read through the manual I can buy a diverter kit and convert from a 2 pipe to a 4 pipe system but the expense makes it unviable. My boiler is a basic WB Greenstar from 2015 so it’s not the best unfortunately and just missed the cutoff point where some extra control was added. Even the ebus connection is disabled. i think I will experiment with setting the DHW to have its own programmed schedule separate from the CH and see if there are any efficiency gains to be made. Link to comment Share on other sites More sharing options...
JohnMo Posted September 15 Share Posted September 15 Can you do this? So long as it's opentherm you should be able to. https://www.ephcontrols.co.uk/section/pdhw/ Or as shown on this video. Cheap and should work. 1 Link to comment Share on other sites More sharing options...
MrPotts Posted September 15 Author Share Posted September 15 21 minutes ago, JohnMo said: Can you do this? So long as it's opentherm you should be able to. https://www.ephcontrols.co.uk/section/pdhw/ Or as shown on this video. Cheap and should work. WB don’t support Opentherm either. I have seen that resister mode before but it only works on the newer boilers. At the time I had the boiler installed I didn’t know about boiler capabilities and thought I was getting a top of the range boiler (that’s what the installer told me), what I actually have is a basic boiler with virtually no control other than setting flow temp. Link to comment Share on other sites More sharing options...
MrPotts Posted September 17 Author Share Posted September 17 Just done some more research and I can buy the diverter kit for my boiler for under £100. If I fit it myself then that is not too bad a cost. The kit needs a return from the HW cylinder but I think I can probably get around that requirement by teeing off the return pipe at the boiler. Link to comment Share on other sites More sharing options...
garrymartin Posted September 17 Share Posted September 17 I have a WB Greenstar 30CDi Classic System boiler. If it's the integral diverter kit you are looking at, it needs to be fitted before the boiler is fixed to the wall so you need to take that into account. Download the instruction manual for the diverter and it will show you what's involved in fitting it. 1 Link to comment Share on other sites More sharing options...
MrPotts Posted September 17 Author Share Posted September 17 I have a Greenstar 24i system boiler. I have the instruction manual for the diverter kit and see the part you are referring too. 1 Link to comment Share on other sites More sharing options...
garrymartin Posted September 17 Share Posted September 17 9 minutes ago, MrPotts said: I have a Greenstar 24i system boiler. I have the instruction manual for the diverter kit and see the part you are referring too. If I can provide any photos of my install or anything that might be useful for you, just let me know. 1 Link to comment Share on other sites More sharing options...
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