Vailant turbomax 828 problems

[vailant828]

Some advice please.

Started having problems with a Vailant 828 boiler about a year ago, where it would not provide hot water (heating was fine). The green light was lighting up when hot water tap was opened, but no how water. This was an intermittent problem, ocurring one or twice a month for a few hours.

More recently, similar problem has arisen where no cental heating as well. Same symptons, no fault codes, boiler sounds like its running but no hot water or heating. The middle amber light is not lighting up.

Leaving the boiler off for a few hours and then re-starting seems to fix most times.

Any ideas - read alot about diverter valve, diaphrarms, micro switches etc. but not sure what the problem may be.

 

[Agile]

Sounds like sticking diverter valve!

When stuck in CH it gives hot rads when you run a hot tap!

When stuck in DHW it gives DHW ok but if left on Ch will fire up every 20 min to warm up the plate HE.

Tony

 

[vailant828]

Thanks Agile. Easy way to prove it is this, and is this a repair that can only be carried out by a gas engineer or a DIY job possible?

Thanks again.