Aplha 240E combi boiler

[DavidHalliday128]

Hi

I have an alpha 240E combi boiler which has a very slow rate of hot water coming from it. When the water is running the boiler is very noisey and appears to heat the radiator at the same time. The hot water goes hot and cold and can only cope when the tap is basically dribbling.

Is there a two way value from the mains inlet somewhere which is functioning incorrectly.
i.e Trying to heat the radiators and the hot at the same time ?

The central heating works fine when no hot water is required.

Many thanks Dave Halliday

 

[gas4you]

You need to change the diverter valve assembly. It is stuck mid position.

 

[DavidHalliday128]

You need to change the diverter valve assembly. It is stuck mid position.

I'm not sure. I'll have a look tommorrow night. Is the value electrically actuated ?

i.e 24V = value hot water position
0V = central heating

Thankyou for the reply Dave H

 

[gas4you]

The valve is hydraulically operated by the HW demand. The cold mains pressure pushes against the diaphragm and tells the DV to move across for HW.

The diaphragm also operates the DHW microswitch at the front of the DV to tell the boiler to fire for DHW.

 

[DavidHalliday128]

The valve is hydraulically operated by the HW demand. The cold mains pressure pushes against the diaphragm and tells the DV to move across for HW.

The diaphragm also operates the DHW microswitch at the front of the DV to tell the boiler to fire for DHW.

Thank for the reply

I've taken the front cover off the boiler. The switch listed in the manual as the DHW value flowswitch appears in the upper position and does not move if the water is switch on or off.(seems to remain with the shaft fully out permanetly
If you turn on the hot water tap the front cold water flow switch come out and fire the boiler as expect(primary water flow switch. This switch is the one which I thought controlled the divertor value not the DHW value switch ??

 

[DavidHalliday128]

The valve is hydraulically operated by the HW demand. The cold mains pressure pushes against the diaphragm and tells the DV to move across for HW.

The diaphragm also operates the DHW microswitch at the front of the DV to tell the boiler to fire for DHW.

Thank for the reply

I've taken the front cover off the boiler. The switch listed in the manual as the DHW value flowswitch appears in the upper position and does not move if the water is switch on or off.(seems to remain with the shaft fully out permanetly
If you turn on the hot water tap the front cold water flow switch come out and fire the boiler as expect(primary water flow switch. This switch is the one which I thought controlled the divertor value not the DHW value switch ??

I lied the upper switch is working fine as well. This must be the central heating flow switch !!

I'll assume the main divertor value assy (4) is Jammed. ?!?
question
Why does the hot water require a second heater exchanger as the water is heated via the upper heat exchanger ??

 

[gas4you]

This is why a combi is either HW OR CH. The DV sends the heated water from the primary HE to either the rads or ths system side of the plate HE.

The plate HE transfers the heat to the domestic cold entering the plate thereby creating hot tap water without the two mixing.

The top switch proves the pump is working.