Worcester 30 hot water issue

[tackit]

Hi,

Hope someone can offer some advice.

I've got a Worcester Bosch 30 combi boiler on natural gas thats been playing up a for while. It's about 10 years old and has already been repaired by Bosch about 4 years ago, having a new heat exchanger plus other bits.

1. When the radiators have been on for while and are nice and hot, the hot water to the taps runs hot/cold. It does not do this when the radiators are off, or just warming up.

And most recently:

2. The hot water flow to the taps has dramatically reduced.

The boiler heats the rads brilliantly. The rads were all removed and flushed this summer. Both faults evident before rads cleaned.

Is this something simple? Or another call out from Bosch, or a new boiler?

Thanks.

 

[picasso]

Blocked cold water filter (causes poor flow rate)
blocked plate heat exchanger (boiler goes hot/cold)
stuck diverter valve

all fixable.

 

[tackit]

Thanks for the reply picasso.

I'll get Bosch out again to repair it based on the likely costs of parts alone.

They did a fab job last time.

 

[tackit]

Had the plate heat exchanger replaced by local plumber! But faults still occur.

The diverter valve motor is going up and down when hot water is demanded from the tap.

He suspects the flow sensor/DHW sensor but cant these until Monday.

Don't want to keep adding parts for no reason. A different sensor fault maybe?

What do you think?

Thanks again.

 

[picasso]

Sorry cant do much more without being in front of the boiler.

 

[tackit]

Just to finish the thread:

New plate heat exchanger gave good flow and fast hot water.

New DHW sensor resolved the diverter valve motor going up and down giving hot/cold water from the hot taps.

New flow regulator and a clean of the old parts resolved the hot water flow rate. Back to 11l per minute.

All sorted thanks to advice on here and local plumber.