I recently had the heat exchanger changed due to a build up of lime scale - Hot water flow rate is now greatly reduced to the extent that when a tap is on downstairs (either hot or cold) no water will come out of the upstairs taps - Is there a control to change the flow rate of the hot water?- The flow from the cold water taps is as good as before .

Peter Smith, July 2006

Flow should increase not decrease with a calorifier (Heat exchanger)... Check that the cold mains inlet to the appliance has been re-opened all the way, there is no flow restrictor in these appliances to my knowledge, so flow rate should only be effected by the isolation cock...

If this doesn't work, all I can think of is that possibly an 'O'Ring or Washer is restricting the waterway... This would only be possible if the old seals were left on the appliance, otherwise you'd be having huge waterleaks by now if the new seal kit wasn't fitted properly...

Let us know how you get on.

ccMods, August 2006