Any help on Alpha HE CB25

[PLUMBPAL]

Hi - I have a curious little problem which is now costing me every spare minute and lots of phone calls which I feel needs sharing before i go mad. I have moved an Alpha HE CB25 ten feet from one wall to another no problems and the only addition was a plume managment kit which is as MI. Since then when the boiler comes up to temperature in either DHW or heating the A & B lights will flash together for around 10secs then it will happily reset itself and carry on for another 1min before same happens again - MI says flue or fan fault....thanks
Whats been done so far after becoming best friends with alpha tech help
1 replaced the fan - same
2 removed the plume kit - same
3 removed the flue restrictor - same (wasnt in instructions)
4 replaced the primary temp sensor
5 measured everything from NTC at varying temp to fan voltage to burner pressure DHW & heating APS so am loathed to replace pcb as it all measures up - same
6 removed the entire boiler from the wall and replaced the condense hose as look kinked - same
7 cleaned out the condense trap and routed to a bucket to check not blocked - same
8 removed the condensing heat exchanger and checked for block/cracks - same
9 checked system water quality - clean

The only indication that its about to lock out is a slight bubbling sound as if water vapour is stuck in the flue Customer has said in heating mode they dont notice it as room stat temp in house is kept quite low but on full blow when showering it keeps cutting out & shower goes cold & i get a call each and everytime.???

 

[Alpha man]

Could be the Air pressure switch, had similar with this once or twice,

Does this only do this after heavy rain and wind?

 

[PLUMBPAL]

No it has been on dry days too no rain - air pressure switch just allows the pcb to know the fan is working right i mean its on or off - would that still throw up both lights and happily reset itself after - i think itsthe flue temp stat kicking in but i have measured continuity across that and the hi limit stat - they appear to be doing their job?

 

[PLUMBPAL]

just a thought i have reused the easy flue telescopic but added a plume kit - can you see any problems there total lenght is 2.6 m including elbows

 

[Billy Bob Bob]

No it has been on dry days too no rain - air pressure switch just allows the pcb to know the fan is working right i mean its on or off - would that still throw up both lights and happily reset itself after - i think itsthe flue temp stat kicking in but i have measured continuity across that and the hi limit stat - they appear to be doing their job?

depends on the alphas set up,some switches are live to aps out to fan sl to pcb,is it a honeywell aps fitted?

 

[PLUMBPAL]

not sure of manufacturer its white & round if it helps - still surely a faulty aps would cut power to pcb & shut down gas valve as safety measure this problem goes flue temp stat as if too hot - just had customer on the phone to inform me the boiler is making the same gurgling noise as before when it has got up to temp - im more and more convinced that its something to do with condense but ive double checked everything i can think of???

 

[PLUMBPAL]

alpha man - why wind and rain what had happened did water enter the switch and cause same fault code with you? - my god david bowie live on radio 2 right now

 

[Billy Bob Bob]

and are you certain the custards not lying? fault was not there before? if the membrane in the aps is going it will cause weird symptoms they dont always just lock out,the gurgling is odd though where have you terminated the condensate?

 

[Alpha man]

When you replaced the fan, was there any water in the fan heat box above the burner?

Those white Alpha air/hubba switches are just as cheap as the CB boiler range, my money is on the APS!!

 

[Alpha man]

The flue will be fine at that length and with a plume kit.

 

[PLUMBPAL]

Condense to spigot on sink trap no more than 1.5m all on fall

 

[Billy Bob Bob]

and dont buy a alpha branded switch get it from euroboiler spares/abkot uk they are a lot cheaper get a rated huba or universal and throttle down to suit

 

[Billy Bob Bob]

Condense to spigot on sink trap no more than 1.5m all on fall

that could explain the gurgling but not the fault,when the plugs pulled on the sink the traps being sucked out of the bottle to alphaman does this boiler have a fly by wire ignition interrupter on the conden trap?

 

[PLUMBPAL]

alpha man- do you mean in the condensing heat exchanger - come to think of it there was some water damage on the old fan thats why i went with tech help to replace it -i had the whole box out to check for debris etc but looked good to me but to be honest first one ive removed so not sure what to look for?

 

[Alpha man]

that could explain the gurgling but not the fault,when the plugs pulled on the sink the traps being sucked out of the bottle to alphaman does this boiler have a fly by wire ignition interrupter on the conden trap?

No it doesnt.

 

[Alpha man]

alpha man- do you mean in the condensing heat exchanger - come to think of it there was some water damage on the old fan thats why i went with tech help to replace it -i had the whole box out to check for debris etc but looked good to me but to be honest first one ive removed so not sure what to look for?

Yep, the box that the fan goes into.

 

[PLUMBPAL]

Yer the box did have some water in it??