Vaillant EcoTEC 837 NO FLOW OF HOT WATER! All aspects of plumbing questions and answers, help, tips and information

[Lectrician]

I drained down my rads to add another, and have refilled the system.

I put the boiler into test mode 0 (CH and DHW bleeding) instead of 6 (filling).

The rads are all working fine, and warming up, but I open the HW taps and there is just no flow at all - nothing.

I had this happen last time I drained down and re-filled, and cannot remember what I did to cure it?!?

How and why does the boiler prevent any flow to the taps?

Cheers.

[sjlheating]

the filling on this combi is by using the same isolation valve as the cold water inlet isolation so i would guess u haven't opened the cold inlet correctly under the boiler

[sjlheating]

sorry ...read that back and it didnt sound to clear.!
if your boiler has an internal filling system ( as apposed to a filling loop added at installation) u have probably turned it the wrong way after filling your central heating. this isolates the cold feed to the combi..hence no hot water comes out of the taps!! thanks