Vaillant EcoTec Plus combi issue - VL-RL Spread too big

[cooldude]

Hi All, I am experiencing a simple problem after trying to re-start my Vaillant combi boiler after draining the system. The problem only occurs with the hot water demand and it appears to relate to a VL-RL Spread (error S.53). What is VL-RL spread and how can I ensure sufficient water flow in the boiler. The Central heating side works OK and the hotwater is where the problem arises.

Any help is most appreciated.



S.53 - Appliance is within the waiting period of the operation
block function due to water shortage (VL-RL spread too
big)

 

[Gasguru]

Is the auto air vent cap loose?

Did you bleed the air from the boiler using the test program detailed in the manual?

 

[gas4you]

You need to check that the F & R thermistors are fitted securely to the respective copper pipes in the boiler, on a straight bit of pipe and not on the concave section so they are not making contact with the copper properly. Several left the factory incorrectly assembled