Mid point 3-port diverter?

[mrcro]

there is a hum from boiler but thought that was the pump noises tranfsferring. When it was working before the usual sequence was pump, then fan then ignite.

Seems to be stuck at pump now.

when It fired yesterday on HW side only same thing, demand for HW by switching to +1hr, hear pump circulating through boiler then fan and light.

If actuator microswitch as you mentioned before should fan be running but not igniting?

Gloworm Ultimate boiler

 

[seco services]

if your getting a call from hw/heating and the pump is working the boiler should fire.
if you loose power pump won't work either.

 

[seco services]

deleted

 

[seco services]

have you been pulling on any wires etc, can you check for power at the boiler ?

 

[mrcro]

OK, so maybe not the controls. Do you know what ignition sequence should be on Gloworm Ultimate?

Is the fact the fan not engaging causing problem with ignition or possibly something else before fan engages isn't happening.

May have just been coincidence yesterday that it fired when only demand for HW but then surely CH would have stayed on once the cylinder stat was satisfied?

Had my head in airing cupboard all day and maybe in wrong place!?

This house is ten year old and original boiler but selling soon so would rather not change boiler if possible!

 

[seco services]

as you say the pump, then you'll hear the fan, ignition etc.
fan maybe just stuck, have you tried give the top of the casing a bang ?
maybe power supply to the boiler, you'll need to check with a elecy meter.

 

[mrcro]

not pulled any wires, power ok to boiler there is an orange glow from PCB and thermostat has on/off click and adjustment know (like on older style radios) which turns that LED on/off so appears to be powered up as should be. There is an additional 'hum' to that of pump you can hear but low, when it fired before it was an increased fan type sould and alot of 'swishing' of water through boiler sounds prior to ignition?

Don't sure if relevent?

 

[seco services]

so sounds like fan not running at full speed.

 

[mrcro]

top of casing banged, no joy!

if fan stuck and I leave it on like have been trying to find fault can it completely knacker fan?

is fan accessible under cover to try free it?

 

[seco services]

can you see the four led lights on the pcb and see what ones are alight ?

 

[mrcro]

i'll have a look, can see and orange one but behind cover so will remove.

 

[mrcro]

there are 2 orange lights lit (more little bulbs than LED, how old is this thing!?)

one looks to have '12' printed on the pcb next to it.

when u turn thermostat on boiler right down and click off just one light remains

 

[mrcro]

then 2 bulbs not lit

No. 3 pressure switch proved and No.4 pilot/pcb proved

 

[seco services]

this is straight from the installers manual.

n0 3 not lit.
check for 230v between n/c and n on air pressure switch.
is their 230v between c on air pressure switch and n ?
does fan run ?
does fan hunt ?

 

[mrcro]

sorry n/c and n

you just lost me to be perfectly honest!