Any tips gratefully received that might help to diagnose my Vaillant 835 ecomax DHW problem.
Symptoms:
Turn on hot tap, boiler fires up, get piping hot water at 60 degrees (as set by the DHW dial).
1. Boiler temp hits 75 degrees (Vaillant default) and boiler appears to scale back its activity
2. burner indicator on LCD display still on
3. burner still going but at what appears to be a reduced level
4. temp of water at tap begins to drop
5. boiler flow and return temps begins to drop...and keeps dropping, boiler doesn't ramp up to previous levels of activity
6. boiler temperature just keeps falling back...to around 40 degrees...with temperature at tap dropping along with it.
At this point I turn the tap off!
Action so far:
a. Measured water flow rate: 14litres per minute.
b. Disabled the warmstart option by turning DHW control to left and then setting DHW temp to 60 degrees. (No 'C' shown on LCD display)
c. Cleaned and descaled Heat Exchanger, which was not too bad...
d. Tried to work out if diverter valve might be to blame....flow pipe near boiler gets warmer but that could just be conductivity of copper....flow pipe 2M from boiler still cold.....so perhaps it's not the diverter.
Other information:
The boiler has been driving an S-plan system for CH and HW, the DHW from the boiler has not been used since boiler installed 6 years ago, i want to feed HW tap in new utility room from boiler HW rather than cylinder HW so this is first time it has been used; so it could be a sticking under-used and neglected diverter valve.....or it could be something else....i am hoping that you helpful types might be able to point me in the right direction.
Many thanks in anticipation...
Phil G.
Symptoms:
Turn on hot tap, boiler fires up, get piping hot water at 60 degrees (as set by the DHW dial).
1. Boiler temp hits 75 degrees (Vaillant default) and boiler appears to scale back its activity
2. burner indicator on LCD display still on
3. burner still going but at what appears to be a reduced level
4. temp of water at tap begins to drop
5. boiler flow and return temps begins to drop...and keeps dropping, boiler doesn't ramp up to previous levels of activity
6. boiler temperature just keeps falling back...to around 40 degrees...with temperature at tap dropping along with it.
At this point I turn the tap off!
Action so far:
a. Measured water flow rate: 14litres per minute.
b. Disabled the warmstart option by turning DHW control to left and then setting DHW temp to 60 degrees. (No 'C' shown on LCD display)
c. Cleaned and descaled Heat Exchanger, which was not too bad...
d. Tried to work out if diverter valve might be to blame....flow pipe near boiler gets warmer but that could just be conductivity of copper....flow pipe 2M from boiler still cold.....so perhaps it's not the diverter.
Other information:
The boiler has been driving an S-plan system for CH and HW, the DHW from the boiler has not been used since boiler installed 6 years ago, i want to feed HW tap in new utility room from boiler HW rather than cylinder HW so this is first time it has been used; so it could be a sticking under-used and neglected diverter valve.....or it could be something else....i am hoping that you helpful types might be able to point me in the right direction.
Many thanks in anticipation...
Phil G.