[Kevin R]

At the moment my hot water system is plumbed in following my resin vessels (I am DI only) and before my hoses. So I am heating pure water just before use.

I run a dual resin system. My question is would your resin last longer or expire quicker if you ran hot untreated water through the vessels.

Boffins welcome 

[Wayne Thomas]

Kev, don't know if your resin would last longer but running hot through it may change the acidic level making it more aggressive. Better to run cold through di into your heater. Also heat would be wasted going through di 1st

[ned]

Kev ran my through Di 25 litres on demand to make pure , cold water using approx 350 to 450 litres a day 8 to 9 weeks , changed over to hot working the same way 3 weeks max , so now fill tank with pure and run hot without going through resin , soft water area   Ned

[Nathanael Jones]

The problem with having the DI after the heater is that the hot water takes ages to filter up through the vessel and down 100 mtrs of hose. You'll have 2 houses done before you get any hot water!!

Peter Fogwill told me hot water is good for the resin, never tried it myself though.