Intermittent hot water

[bigH]

Hello,
I have a problem with my potterham boiler. When the central heating boiler is on I can get continuous hot water. When the central heating is switched off I get intermittent hot water. The BG engineer came around and said that it is scaling in the pipes and it needs de scaling. He then recommend that I get a unit call hydropath and it will cost £150 to install.
My concern is that if I do go ahead and do this install it may not fix the problem. Therefore does anyone have an idea what could be the issue, if the engineer is incorrect?
Thanks in advance, H

 

[gas_man_gaz]

make and model of boiler would be handy

 

[bigH]

Hello gas_man_gaz,
The boiler is a Potterton Puma 80.

regards H.

 

[baxpoti]

Are you in a hard water area?

Regardless of hot water OK when heating on, you do have intermittent hot water.

The hot water flow and microswitches are common failures as is the diverter valve

These need to be eliminated.

 

[bigH]

Hello baxpoti,


Are you in a hard water area?

No idea, I am in SW london

Regardless of hot water OK when heating on, you do have intermittent hot water.

When the central is switch off i.e. Summer time I get intermittent hot water. when the the central heating is on I can get continous hot water

The hot water flow and microswitches are common failures as is the diverter valve

These need to be eliminated.

The British gas engineer told me that it is a lime scale build up in the pipes which I am not sure about

 

[baxpoti]

The British gas engineer told me that it is a lime scale build up in the pipes which I am not sure about

Nor am I

 

[nogoodatfaultfinding]

For what its worth i tend to find when i come across this problem its either the diaphram or the flow switch sticking, 9 times out of ten it will be the diaphram.
This is a generalisation on all combis not your make alone.