Hi ,I have a vaillant 828e T/max dhw is Luke warm at its very best, I have replaced thermistor 1,cleaned plate heater .The diverter valve is working fine as is the heating side the boiler is 12 years old,can anybody advise.

Amrick, February 2013

Hi Kash bought new plate exchange about 50 quid from eBay works a treat,thanks for your help

Amrick, February 2013

i thought so. u cant flush it with water u need to clean it properly by dissolving the iron oxide inside the heat excahnger. to do this go to the plumbing merchants or ebay and buy senteniel x800 jetflo cleaner. now boil a kettle of water and find a small bucket. fill the bucket with the x800 cleaner tub. then add the kettle of boiling water. then put on rubber gloves and put the heat exchanger in the bucket. leave it in there for two minutes. then while its in there after two minutes shake it around turning upside down. then remove it upwards so the water drains back into the bucket keep doing this for around 10mins then just wash it out with clean water and refit the heat exchanger to the boiler. if the heat exchanger is to badly blocked then u will require a new one on ebay u can now get chinese copies of them that are just as good as vaillants for half the price

kash, February 2013

Hi Kash I flushed it out under running tap water and blew Thur it ,water was free flowing and no debri came out,what I have notice the two pipes which feed the plate heater via the heat exchanger are very hot to the touch the dhw coming out of the plate heater is only Luke warm

Amrick, February 2013

how did u clean plate exchanger

kash, February 2013