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Vaillant ecotec plus 824 - pump overrun (s.7)
I have the ecotec plus 824. I never had any problems with it and then suddenly the heating would not come on. I called out an engineer who apparently replaced a part that switches it between hot water and heating as this was not switching over to heating. There was also a small amount of water inside which the engineer said was nothing.
Since I have had this problem, whenever I am using hot water or heating 2 symbols are on the screen constantly which I never noticed them there before. After looking in the manual they mean "gas valve is activated" and "internal pump is running" no matter how long heating is on these symbols are always there. When I press the "I" button it says "S.7" which in manual says pump overrun.
I am not familiar with the system to know if this is normal or what it could mean? Any advice would be welcome. Thanks
1 Answer from a MyBuilder Plumber
Best Answer
Hi, the initial problem is one of a very few common faults on all vaillant combi boilers. The diverter valve motor can stick or stop working, this can be replaced without the valve body. This is probably the reason there was water at the bottom (front probably) of the boiler as water can leak up through the spindle of the diverter valve as this is just an interference fit seal.
The next few things I wouldn't worry about. It sound like the boiler is doing what it should and if it wasn't there are that many fail safes on modern boilers a fault code would show on the screen ie F.22 low water pressure. The pump over run is something that all modern low water content boilers have built in to protect the heat exchanger and get rid of any residual heat. Obviously if the pump is running constantly, even after the hot water pre heat function has finished, I would get back in touch with your engineer as there is a problem. Hope this helps.
Answered 12th Apr 2014
