DHW issue with DPS heatbank

[johnykp]

Good evening guys, I've been in my current house for just over 12months and can't seem to fix the issue we have. We only seen to get half a bath of hot water before the water goes lukewarm. I have a Worcester 30cdi boiler and a dps cpc250-abbdi-laab heat bank. The system supplies 14 rads over 3 floors and 3 ufh zones, I have never had an issue with the CH. I have tried all sorts of different things but to go avail. Any ideas what could be causing the water to go Lukewarm after about 10mins?

Both stats are set at 70,the Combi sits about 84-88c, the DHW pump is a new grundfos ups2, the heat exchanger pump is a wilo rs26/6-3. The Combi has had a full service check with so issues . The system is running at 2bar and there is magnaclean installed. Both heat exchangers are 100kw.


Read more: https://www.diynot.com/diy/threads/dhw-issue-with-dps-heatbank.499067/#ixzz5917UyaDX

 

[king of pipes]

Somethings not right here there are alot of your comments which are confusing , firstly how old is this system , why do you have a combi supplying a heatstore type cylinder, 84-88 degrees c ?, you have a 30kw boiler trying to supply 2 100kw heat exchangers , you have quite a large heating load there , when you replace parts on the heatbank it should be like for like , i would advise you employ a GSI to look at this . cheers kop

 

[johnykp]

Gsr? This is the system that was in the house when I bought it, I believe the system was installed in 2011, the system has run fine, however the person I bought the house or said they had just changed the HW pump the week before we bought it is it was faulty, I have no idea what pump was in previous to the grundfos. I live at the fathermost part of Scotland so their isnt any heating engineers local to look at this

Thanks

 

[Bogart]

I had a DPS thermal store many years ago with 2 heat exchangers running off a 24KW boiler and got lots of DHW. If DHW runs out quite soon I can only assume tank is not hot enough for one reason or another or the pump that is switched on when a tap is opened is somehow switching off.