Ravenheat intermittent hot water

[dan12345]

I've got an he85t ravenheat combi. It's been fine for about 3 yrs but has recently started to run a luke warm bath. I took a look at it while the tap was running and it seems the boiler fires up for 15-30 secs, then goes out, then fires up again for 15 to 30secs or so. The result is a luke warm bath cos it's not heated all of the water.

CH is fine, luckily!!

Any ideas? Thermistor maybe?

Thanks.[/b]

 

[landyandy]

Possibly the diverter valve.

Andy.

 

[dan12345]

Possibly the diverter valve.

Andy.

Thanks Andy, is that towards the bottom of the bolier with a series of bolts around it's outer edge? I've also just noticed that there's a very very slow drip coming from this part too..?

 

[landyandy]

Thats sounds like the one.

 

[Marc86]

Id be checking thermistors first, not sure why the diverter valve would make the burner heat up for 15-30 seconds?

 

[dan12345]

Id be checking thermistors first, not sure why the diverter valve would make the burner heat up for 15-30 seconds?

Hi Marc, I went with the advice of a friend who had a similar problem and replaced the diverter at a cost of £50. Well I still have the same problem!! Would you mind explaining which thermistors I should try replacing please? I'm hoping they're cheaper than the diverter!!

Thanks.

 

[combispecialist]

check thermistors yeah but what uve said indicates a blocked plate/plate h-exchanger

 

[dan12345]

check thermistors yeah but what uve said indicates a blocked plate/plate h-exchanger

I also get lots of noise from the rad which I think is closest to the boiler after the hot tap has been turned off. The noise sounds like air (maybe?!) and stops about 10-15 seconds after the hot tap has been turned off..