There are several reasons this valve may stop working properly. No Heat.
On 2021-11-28 by Tim.
If you aren’t sure whether your diverter valve is working properly, it’s fairly easily to diagnose the problem.
.
The most common signs of a boiler gas leak are usually the smell, blackened spots on or around the boiler and condensation on the windows; A gas leak occurs.
The igniter would start again, and the cycle would repeat.
.
.
To inspect the valve’s components isolate the valve from voltage and fluid.
.
Run a hot-flush, or power flush to remove any sludge.
.
.
The most obvious sign of a broken or faulty boiler zone valve is a zone that won't heat up at all.
#7.
A flickering flame can be an early warning sign that the burner needs to be cleaned.
Try turning on the thermostat and feeling.
.
.
Faulty Gas Valve.