Viessmann EE FAULT

Tonerlow

We have a 200000btu Vitodens 200w providing slab heat to a 6500 ft2 shop at work. Getting a repeated fault of EE combustion lockout. Looking here for first things to investigate ? 

GGross

EE, is a no flame signal error, if you get these intermittently you may also see EB which is no flame signal during calibration.

Flame sensor and igniter are possible culprits, depending on the age of the equipment you may be due to change them anyway

Check that the condensate drains freely, burner chamber is clean etc

confirm what type of fuel you are using, if LP confirm you have fuel..
Check gas pressure incoming to the boiler at gas valve. Static gas pressure should be within operating range for your fuel type, listed on the side of the boiler (check that you are looking at the correct fuel type)

Record gas pressures.
-Static pressure before ignition
-Pressure drop at ignition
-high lockup pressure after burner shuts down

repeat the gas pressure testing with a full load, meaning everything that uses gas attached to the same regulator on at the same time

measure and record your gas piping size and total length from the boiler to the regulator.


If you do not know how to correctly check the gas pressure, then you should call a service tech in.

Paul Pollets

Is there a Low Loss Header on the piping?

Tonerlow

Yes low loss header. That feeds 2 manifolds for the slab (2 Zones/2 thermostats)