Ravenheat RSF820/20 Hot Water Issue

[Poisonata]

A problem has developed with the on demand hot water with my Ravenheat RSF820/20 Combi boiler.

This evening I noticed that when I turn on the hot tap, in order to fire up the boiler I need to turn it on full. Normally (up till this evening) the hot tap only needed to be partially open to fire the boiler up. And now of course when the hot tap is fully opened only luke warm water exits as boiler hasn't a chance to heat it up.

Everything else is working fine, the actual firing up of the boiler seems normal, the heating is fine, I guess it is some flow regulation / detection valve that is at fault.

Anyone point me in the right direction please. My thanks in advance.

 

[tininho]

Sound like a fault with the Domestic Hot Water diaphragm or the diverter valve to me....

Martin

 

[Poisonata]

Sound like a fault with the Domestic Hot Water diaphragm or the diverter valve to me....

Martin

Thank you. The diverter valve we had replaced some 6 years ago when it got stuck and we had only hot water or heating (can't remember which). Do these valves have a fairly short life expectancy ?
I will need to read up about Hot Water Diaphragm as this part I am not familiar with.

Many thanks for taking the time to respond.

 

[tininho]

He DHW diaphragm is housed in the domestic manifold section of the diverter valve (the lard disk like section)..... But of a bugger to change....

Best of luck

Martin