central heating not working but hot water fine

[lee1234b]

Hi, i have a vaillant ecomx 824e the trouble is 6 days ago the central heating as stoped working , but the hot water is working fine the flow pipe off the central heating is getting hot for about 2 metres and the rad above the boiler is getting loop warm if that. some times and not always a code is displayed on the boiler saying e 13 , i have taken the case off and checked the diverter valve i hold down the plastic switch on the actuater diverter valve in the central heating mode and the rads all started getting hot when i let go again the switch moves back up and after a few seconds the boiler cuts out , any advice or information would be a great help.............

 

[plumbplumb]

Sounds like all external controls are calling for heat I.e clock/roomstat and the boiler is firing but the diverter motor is not shifting the boiler into heating mode and just circulating round the boiler as if in HW mode but because no tap is running no heat is being removed from the boiler.

Sounds like diverter valve head (by what your saying)

If you manually move the diverter into heating position and all gets hot I'd plump for that

 

[lee1234b]

thanks for the reply, sorry i forgot too mention that i have changed the actuator diverter valve and it still does the same, when the boiler is switched on in central heating mode you can see the valve move it to central heating mode but after a minute or so it moves back up and the boiler cuts out. I was thinking maybe it could be the diverter valve body, or what the man at the technical advice centre for vaillant said is too test the flow switch..

 

[plumbplumb]

If the heating is switched off and no water is running does the boiler fire on it's own?

 

[lee1234b]

no, the boiler doesnt fire up on its own unless the central heating is in demand , the hot water side is fine no problems.....

 

[plumbplumb]

That more or less rules out the HW flow switch

(presuming that's what he meant as these boilers I'm sure don't have a pump flow switch they work off heating sensors flow/return differentials)

Though you could try unplugging it and running heating to eliminate it

 

[lee1234b]

ok i will try unplugging the wire too flow switch and fire it up in central heating mode, if the boiler stays on in central heating mode would this mean its the flow switch..... if the flow switch is ok could it be the diverter valve body getting stuck. some times the code e 13 appears when the boiler shuts down

 

[plumbplumb]

S, D or F are the codes on these are you sure it's not S13 which would indicate a DHW operation

 

[lee1234b]

am sure, i have the manual in hand it says e 13 water deficiency error - appliance blocked,maximum permissable temperture rise of ntc1 has been exceeded appliance blocked for 10 minutes.......

 

[plumbplumb]

Ok. Rules out flow switch.

If you can push diverter to heating and boiler runs fine and rads get hot (without error codes) it suggests an issue with the diverter valve itself

 

[lee1234b]

thanks for your help mate , am going to change the diverter valve body tomz see if that does it..........

 

[plumbplumb]

keep me advised