Biasi Riva m90 24s DHW problem

Hi everyone,

This is my first post apologies if it seems like ground that has been covered, but I have searched the forums and can't quite find a solution...

I have a problem - I can get hot water if I restrict my flow to approx. 3l/min but when I open the hot tap fully open [7 l/min] the water is at best lukewarm... This is a real problem when running a bath as it takes 20 mins to fill a lukewarm bath.

The temp on the boiler reads 65 deg C with the bath tap on full, but the water coming out of the tap is only 35 deg C. I f I restrict the flow to 3l/min I get a healthy 47 deg C out of the bath hot tap [the temp on the boiler now reads just above 60 deg C. Distance is approx 6m.

I have gathered from the forums that this could be a number of problems, but I wondered if my symptoms pointed to something more specific...

Any advice would be much appreciated! Thanks in advance...

Kind regards,


Nick[/url][/quote]

Since the boiler isn't getting hot enough my guess would
be the diverter valve isn't diverting fully to hot water.

Thanks for the reply... is there anything I can do to test it out? Looking at the manual it looks like a complex job, any tips...?

Thanks in advance,

Nick

nickdiacre said:

Thanks for the reply... is there anything I can do to test it out? Looking at the manual it looks like a complex job, any tips...?

Thanks in advance,

Nick

Click to expand...

I think there is a diverter valve service kit. £45

This model has a diagphram and it could be that ?
Turn the central heating on and run the hot tap at the same time and see if it works ok.If so it's a 30min job and the last one i did cost about £9.

When the heating hasn't been on and flow is cold, turn on the hot water.
Feel the flow pipe and see if I gets hot. If it does then diverter valve is faulty.

This boiler has a Hall effect flow sensor and a motor driven diverter valve!

How would Bob deal with that?