Why does my bosch 25e ingnite then blows out repeatedly and occasionally stays on if i turn tap on and off and on for abit.

SOURCE: Central heating and hot water have suddenly stopped working

not an engineer but maybe a heating compant,, it sounds like you have a relay that has gone bad, you have what we call a winter summer system your domestic water comes from a tank inside the boiler, you might want to think about splitting the system to save you some money in the long run, seperate the water heater from the boiler so you only heat up in the winter, right now you are heating the system that heats your house to get 30 or 40 gals of domestic hot water, it would cost you less by seperating them

SOURCE: baxi duotec is heating radiators but not tap

Sludge / furring possible in primary part but not if the ch & flow through hot tap are ok More likely it's the diverter valve. The rubber diaphragm inside is perished / holed. Replace

SOURCE: bosch 25e water heater wont ignite

combi or standard if combi pressure too high and will be blowing off your high pressure release valve which would stop your boiler from igniting best of luck

SOURCE: Bosch Aquastar 2400E LP Does Not Heat Water

Sounds like the water flow sensor and servo, may just need cleaning, get it checked out by a Bosch agent

SOURCE: no heat, no light, has flow and power?

I'm experiencing the samething it's been installed 3 years and christmas day nothing. Please help.