Hi everyone,
I have an Ideal Isar HE24, and yes before I get a barrage of abuse it was installed when I moved into my newbuild a little over 2 years ago, I'm aware of their reputation! I've noticed a decrease in hot water performance, to the extent that now to have a hot shower I have to noticeably reduce the flowrate. I took some measurements about 6 weeks ago, and whilst I struggled with repeatability I reckoned I was getting maybe an average of 12kW heat output at varying flowrates for a tap right next to the boiler (so little loss from pipework) - some way off the 24kW expected mark!
I had a dig around and after checking the thermistor resistance in both hot and cold water (which seemed within spec) and also checking that the diverter valve appeared to be functioning correctly (no apparent circulation on CH circuit when only DHW is requested), diagnosed that the problem was likely to be the secondary heat exchanger getting caked in crap. I hired a powerflusher and ran some Fernox DS40 through it for a little over an hour, which seemed to improve things a bit (reckoned I was getting maybe 16kW off DHW afterwards) but still not at what I would expect, and still having slow or lukewarm showers.
I recently installed a new thermostatic shower as the previous one wasn't in great condition and it was actually cheaper to get a new mixer and all than the spare shower head etc. Both the thermostatic showers have suffered from this issue, so I don't think it's anything to do with the thermostatic valve - just a lack of DHW performance. I'm tempted to just fit a new secondary heat exchanger, as apart from the primary circuit heat output I don't see what else the problem can now be. Does anyone have any thoughts on this? Also, I've been looking for spares and can only find the WILO waterset spare readily available online, but I have a CP waterset. They are listed as separate parts in the manual, but some sites suggest that the CP part has been replaced by the WILO one - are they interchangeable or do I need to hunt for an obscure spare part?
Many thanks in advance for your advice,
Chris
I have an Ideal Isar HE24, and yes before I get a barrage of abuse it was installed when I moved into my newbuild a little over 2 years ago, I'm aware of their reputation! I've noticed a decrease in hot water performance, to the extent that now to have a hot shower I have to noticeably reduce the flowrate. I took some measurements about 6 weeks ago, and whilst I struggled with repeatability I reckoned I was getting maybe an average of 12kW heat output at varying flowrates for a tap right next to the boiler (so little loss from pipework) - some way off the 24kW expected mark!
I had a dig around and after checking the thermistor resistance in both hot and cold water (which seemed within spec) and also checking that the diverter valve appeared to be functioning correctly (no apparent circulation on CH circuit when only DHW is requested), diagnosed that the problem was likely to be the secondary heat exchanger getting caked in crap. I hired a powerflusher and ran some Fernox DS40 through it for a little over an hour, which seemed to improve things a bit (reckoned I was getting maybe 16kW off DHW afterwards) but still not at what I would expect, and still having slow or lukewarm showers.
I recently installed a new thermostatic shower as the previous one wasn't in great condition and it was actually cheaper to get a new mixer and all than the spare shower head etc. Both the thermostatic showers have suffered from this issue, so I don't think it's anything to do with the thermostatic valve - just a lack of DHW performance. I'm tempted to just fit a new secondary heat exchanger, as apart from the primary circuit heat output I don't see what else the problem can now be. Does anyone have any thoughts on this? Also, I've been looking for spares and can only find the WILO waterset spare readily available online, but I have a CP waterset. They are listed as separate parts in the manual, but some sites suggest that the CP part has been replaced by the WILO one - are they interchangeable or do I need to hunt for an obscure spare part?
Many thanks in advance for your advice,
Chris
