Vokera Linea 24 Domestic Hot Water Problem

[carl897]

My linea 24 Central Heating is working fine.

Hot Water is only giving luke warm, temp. is at 34 degrees. but whe flow at tap is closed the temp shoots up to 90 deg. on boiler display.

I have checked: The water pressure at mains Motorised Valve

I have replaced: domestic heat exchanger thermister on main heat exchanger. thermostat switch on main heat exchanger. thermister near dhw heat exchanger. non return valve on bottom right of dhw heat exchanger. Also replaced the valve bobbin in diverter valve (bottom left, locate behind motorised valve). Also replaced the water pressure switch, But have not touched th adjustable plastic screw heads on this switch.

I have noticed that the 22mm pipe that connects to "Diverter Valv Manifold" (main brass housing at bottom left) is very hot indeed, Bu the Domestic Heat Exchanger (DHE) body is luke warm. And so is the Ho water outflow pipe. As soon as the tap is closed, the temp shoots up t

90 and the DHE begins to get hot to same temp as main feed pipe.

Many thanks for your help

-- carl897

[Ed Sirett]

You have replaced all the parts I would have thought worth replacing.

Does the heating flow pipe get very hot during DHW operation? If so then the diverter valve may need to be looked at again.

Failing that then I think there must be a near blockage into or out of the secondary heat exchanger.

[John]

I take it the flow rate is not exceeding the ability of the heat source?

[carl897]

Water Pressure at tap is about 10litres a minute, and yes the Main 22m

pipe which leads to DHW heat exchanger does get very hot.

Thanks for your help

-- carl897