Worcester 24i wots going on?

[hi1]

Combi, mains gas, 9 years old

1.hot water upstairs runs warmish then back to cold then warm again. Makes no difference if flow is slowed by shutting tap. Water flow same as before this started. Water has been hot during the 'summer' and this seemed to start when selecting heating and hot water. There is no change if heating is deselected. Rads temperature o.k.

2.Boiler operates, fan and pump running but no flame, will do this for hours. Power off and on and it fires up. Is there not a safety system that if no flame detected then boiler turns off? Why doesn't it fire up first time round?

Thanks

 

[tomy]

Is the pressure guage reading about 1 to 1.5 bar ?? does the reset button need resetting ??? , doe sit work on heating or is it just the same?

 

[malkie]

Does it try to ignite a few times then after a few goes it will,if so it could be that it will ignite after a few goes because theres enough gas let through to ignite,it may be theres not enough gas to ignite it first time so may be gas valve or the gas inlet needs opening to allow more gas through

 

[hi1]

Tomy Pressure o.k at 1 and abit at rest goes up to 2 when heating on.

Malkie It goes through the sequence of firing up just the once, theres no flame but fan and pump are running on heating, just fan for hot water, and continue to do so until either heating turns off by timer on boiler or the tap is turned off. if power turned off and back on and heating still on with timer then it will fire up. If you turn off tap then power off on turn tap back on then it will fire up 9 out of 10.

 

[nickso]

following a natural sequence through its operation.....demand-pump-fan-aps-then probably thermistor then gas.

you need to check what is happening on the sequence from the pcb to aps to pcb to thermistor to pcb to gas valve.

try and get a manual for it, worcs fault finding is pretty good.

 

[hi1]

Thanks for that nickso, in fact thanks for all replies. Is thermistor corgi or something i'm allowed to do myself? obviously gas valve isn't and i wouldn't have a clue with the pcb.

 

[nickso]

Thanks for that nickso, in fact thanks for all replies. Is thermistor corgi or something i'm allowed to do myself? obviously gas valve isn't and i wouldn't have a clue with the pcb.

thermistor is ok. gas valve probably not ok.

you dont need to test anything on the pcb really, just test what is coming out of and going into it. get the manual and follow that, most likely it will be looking for various resistances on the multiway cable on the right side of the pcb.

at the moment it seems you have stalled at the aps stage of operation so i would be looking to that first.

 

[hi1]

Sorted, changed the thermistors, start cheap work my way up, 14 quid + some pennies. Now have toasty hot water upstairs, just makes the bread soggy. Thanks for time and replies gents.