Only warm water not hot, but radiators work fine

[eNJayBe]

Hi,

since about Christmas we've been having problems with hot water not being very hot. It has gradually got worse until now we need to boil the kettle for washing up. The radiators still work fine though.

The boiler is an Ideal Classic NF 40.

The pipe that goes into the cylinder to heat the water is hot, and the pipe that comes back out is cool. The pipe that draws hot water out of the pipe is also cool. If I turn on the hot water without the heating the radiators get hot but the water still does not heat up. Water from the taps intially warms up but then goes warm again. There is no immersion heater.

I've tried adjusting the thermostat on the cylinder, it doesn't make any difference. However if I turn the thermostat right down, everything stops and when I turn it back up again I hear it click and everything comes back to life.

 

[gasmick2]

hi it could be a couple of things a blockage in the return on the coil
but i think its the motor in the diverter valve, just look on the end see if there is a lever push it over and see if the return gets hot make sure your boiler is running, if it gets hot then its a new motor or in some cases a complete new head to the valve

hope this helps mick

 

[Agile]

Its probably more likely to be sludge blocking the heating coil.

If playing with the motor valve does not cure it then turn off all the rads and add DS40 to the system and see if that dissolves the sludge. Use about 1 1/4 on the pot first.

Tony

 

[eNJayBe]

I moved the lever last night and it hasn't made any difference.

Sorry to be thick but where do I put the DS40 into the system?

Thanks for the help.