Hopefully someone can shed some light on this for me:
Recently moved into a new house which has a vaillent 824 combi fitted.
Hot water initially would come on very hot then quickly go cold. I checked the outlets and the heating loop was getting hot on DHW demand so changed the diverter valve.
That improved matters in as much as the hotwater is now at constant temp but still not at the sort of flow I would expect.
Spec is ~8l/min at 35deg rise, I'm only getting 5l/min @ 25deg!
Initial thoughts were that the heat exchanger was fouled but the loop return temp is onlt at about 35deg which suggests to me that the heatx is working - all the available heat from the loop is being taken out by the DHW flow, just as if the burner is not putting enough in.
I did wonder if the DHW temp sensor was shot but I changed that too and it made no difference, for some reason you can't read that one from the diagnostics.
Hope someone can help, it's driving me mad now!
Recently moved into a new house which has a vaillent 824 combi fitted.
Hot water initially would come on very hot then quickly go cold. I checked the outlets and the heating loop was getting hot on DHW demand so changed the diverter valve.
That improved matters in as much as the hotwater is now at constant temp but still not at the sort of flow I would expect.
Spec is ~8l/min at 35deg rise, I'm only getting 5l/min @ 25deg!
Initial thoughts were that the heat exchanger was fouled but the loop return temp is onlt at about 35deg which suggests to me that the heatx is working - all the available heat from the loop is being taken out by the DHW flow, just as if the burner is not putting enough in.
I did wonder if the DHW temp sensor was shot but I changed that too and it made no difference, for some reason you can't read that one from the diagnostics.
Hope someone can help, it's driving me mad now!
