Vaillant Ectotec Plus 937 Boiler Problem

[gladyslynne]

Hi everyone. About a week ago, our Vaillant 937 began to display fault codes F81/F91. The temperature on the display would rise rapidly from zero to 80 in a couple of seconds thereby shutting down the boiler. initially, this was on the heating side because with it turned off the hot water worked happily. Now the symptom has spread to both sides and nothing works. The boiler fires just fine but within seconds cuts out because of the rapid rise in temp. Any ideas.
Many thanks Lynne

 

[Agile]

Sounds like a pump/flow problem.


But you will need an engineer for that model, they are not suitable for DIY.

Tony

 

[Tipper]

Get Vaillant to come and do a fixed price fault repair.

A little pricey but they fix everything they find on the same visit and even upgraded some parts in mine to latest spec. Also guaranteed for 6 or 12 months - can't remember which now.