Worcester Combi Oil Boiler. No Hot Water When Heating On.

[ProDave]

Worcester Daneismoor HHSC 190SO  oil fired combi boiler.

When the central heating is on, turning on a hot tap just gives cold water.

Turn the central heating off, hot water works fine.

The plumber has been and replaced the flow switch, the 3 port valve inside the boiler and the thermostat. and given up.

Before I go any ideas? Anyone know this boiler?

 

[Badger]

Worcester Daneismoor HHSC 190SO  oil fired combi boiler.

When the central heating is on, turning on a hot tap just gives cold water.

Turn the central heating off, hot water works fine.

The plumber has been and replaced the flow switch, the 3 port valve inside the boiler and the thermostat. and given up.

Before I go any ideas? Anyone know this boiler?

new boiler :slap :slap ]

 

[SLIPSHOD & SLAPDASH]

Diverter valve ?

 

[SLIPSHOD & SLAPDASH]

If the diaphram is split it wont move to switch the hot water flow

 

[den123]

diverter valve

 

[dave2]

Sounds like the diverter valve.

Let the radiators cool then turn the hot tap on. If the rads get warm it is definately the diverter valve. 

Did the plumber replace the valve and the head?

I have a load of manuals to hand but unable to locate a Danesmoor Combi.