vaillant turbomax 242/282 problems

[roodini]

Hi We have as above, the hot water did not work as it should. the boiler flame out light kept coming on. The water worked for a short time once the reset had been done but then the red light came back on. i have changed the diverter valve for a new complete 1 and also replaced the secondary heat exchanger. the boiler worked like a new one for a few hours then the same problem has returned. the red light comes on showing no ignition. if we reset it we get good hot water. Please any further suggestions?
cheers
Andy
the boiler is i would say at least 10 yrs old

 

[Deleted member 105431]

Call vaillant would be my advice but it's possibly the pump flow switch

 

[roodini]

thanks, i think i will have to. but they may blind me with science. lol.
anyone else with some idea's?
andy

 

[Gasguru]

It could be a genuine burner lockout or as mentioned before the lockout light is also used to indicate the failure if the differential water pressure switch. Often the small bore tubes block or the connection points block.

Change the aav since any trapped air will also prevent proper differential pressure.

 

[roodini]

im no technician so can you tell me what the aav is? anything else i could change whilst stripping the old girl down? as i say i've changed the diverter valve and the smaller heat exchanger. when switched on the hot water is fantastic, but the boiler keeps cutting out!
cheers
Andy

 

[petit_pablo]

AAV = auto air vent. Its located on the pump housing, the brass cap with a vent cap. a new one will probably come as a complete unit with 3/8 threaded end. Just unscrew top cap and fit where the old was.

The pump flow switch can be slow to react and give your fault. Its the plastic lump just up to the left from the pump with the red microswitch, it should shoot up quickly when pump runs and drop down quickly when it stops. The small pipes attached to it can become blocked particularly at the pump end. Remove and check these to for blocks

 

[roodini]

thank you for that i will replace both items as i believe they are not too expensive. is there anything else that could give the same symptoms?
regards
Andy

 

[spacethegas]

thank you for that i will replace both items as i believe they are not too expensive. is there anything else that could give the same symptoms?
regards
Andy

the pump flow switch will not require replacing, just tubes clearing (if necessary) as was explained.

 

[roodini]

ok thanks for that, its, just the copper tube that runs to the diverter valve i assume?
Andy

 

[spacethegas]

Often the small bore tubes block or the connection points block.

The small pipes attached to it can become blocked particularly at the pump end. Remove and check these to for blocks

 

[roodini]

Ok i have changed the diverter valve, the auto air valve, the secondary heat exchanger, the small pipe between the d/v & the flow switch and still the blooming boiler cuts out after a short time leaving me without any hot water. Could it be a temp sensor cutting it out? i'm getting desperate now as most of the tricky stuff has been replaced for new items? Any help/ ideas would be welcome
cheers
Andy