Valiant ecotec 637 pressure sensor playing up?

[EAST61]

checked the pressure on the boiler after it had been off all day and it was showing 0.6 bar with the maintenance symbol flashing.

Opened the 2 valves on the filling loop for like less than a second and it shot up to 1.1 bar where it’s sat for the past few hours.

Honestly the tiniest amount of water must have entered the system, I don’t see how the readings can be accurate. This is a big system with 20+ rads.

What do you think?

 

[heatservice]

Sound like the expansion vessel is flat which is not uncommon with Vaillant boilers.

 

[EAST61]

Thanks, we have an external expansion vessel to support this large system.

System seems to be running normally aside from this blip.

 

[Gasguru]

Pressure sensors on these are the worst in the industry...they're almost an annual service part they're that bad.

 

[MTCH]

External vessel is a good idea as only a 10l inside your boiler so probably undersized for your system. One of the main underlying causes of boiler breakdowns, undersized or incorrectly charged expansion vessel, often overlooked by installers.