intermitant DHW from combi boiler

[paulrmx]

Ideas wanted,
Biasi combi boiler, 2 years old
CH works fine, DHW works fine for a few minuets and then kicks in and out, not good in the shower
Temp ranges from 75-80 deg if this is any help.
Thanks

 

[Agile]

Plate heat exchanger blocked because the installer did not clean the system properly.

Tony

 

[paulrmx]

Plate heat exchanger blocked because the installer did not clean the system properly.

Tony

Thanks Tony, What should the temp be while DHW is running.

 

[bengasman]

If I remember correctly, what you are looking at is the temperature of the primary circuit, the tap temperature depends on the flow from the tap and the temperature of the incoming water.
In your case it will go up and down because the secondary hex can not dissipate the heat.
The boiler manual will give you the normal temperature/flow parameters.

 

[Agile]

It does not actually.

However as always its about 15-20°C above the hot water temperature and normally in the range 55-60°C.

Its irrelevant to the OP what it normally is.

All he needs to do is understand that people who fix boilers are not all total thickos who left school at 15 to become plumbers!

Tony

 

[kevplumb]

It does not actually.

However as always its about 15-20°C above the hot water temperature and normally in the range 55-60°C.

Its irrelevant to the OP what it normally is.

All he needs to do is understand that people who fix boilers are not all total thickos who left school at 15 to become plumbers!

Tony

yeah we all didn't leave school at 15 to become radio repairmen either SMARTASS