Apollo fanfare 30/50i firing up and cutting out

[AC427]

Hello I am having problems with an Apollo Fanfare 30/50i.
It will fire up for approximately 10 minutes then cut out, then fire up again for about 45 seconds then cut out again, repeating this.

The heating system is a microbore system thinking this was a flow problem and have flushed this through every year for the last five years with a system cleaner. Thinking it maybe a flow problem I have just switched the boiler over to the hot water circuit but it repeats the same thing,

The overheat cut off has been replaced and the high and low thermostats have been checked but it makes no difference to the boiler if switched into low or high. The pump has also been replaced.

Im beginning to think it is either a defective solenoid valve within the gas valve or a fan pressure switch, which Im probably going to have to leave to a gas safe engineer.

Any suggestions to the possible cause and rectification would be much appreciated??

 

[twgas]

Sounds like a circulation problem, does heat go through the cylinder coil when HW is selected?

 

[kevplumb]

does it have a bypass fitted

 

[AC427]

On initial fire from cold heat does go through the cycliner coil on hw selection for 10 minutes before the boiler cut out and does it fire up for 45 seconds cut out for two minutes routine.

A bypass has been fitted in the form of a 15mm reduction from the 3-port valve via a gate valve.

 

[J_N30]

Sounds like a flow problem.

What colour is the water in the system? Any rads slow to heat? A proper powerflush would be better then a drain down TBH.

 

[kevplumb]

A bypass has been fitted in the form of a 15mm reduction from the 3-port valve via a gate valve.

has it been altered

 

[StevenJames125]

try checking the pump is running properley?

 

[AC427]

The gate valve has been adjusted a number of times to see if it is a flow problem.

On drain down, the colour of the water is clear, but I have added a de-scaling agent a couple of days ago.

I have err bypassed the overheat cut out and high and low thermostats on the pretence that it maybe a flow problem and timed the boiler on fire up but it still cuts out after 10 minutes. If it was a flow problem I would have expected it to continue running. A bit unorthodox I know.

So leading me to assume the gas valve maybe the solenoids or micro-switch in the fan but this is probably left to a gas safety engineer.

 

[AC427]

Fitted a new pump but still the same thing.

 

[StevenJames125]

has the boiler always been like this? could be a pump overrun issue? could be a blocked manifold somehwere in the system....

 

[AC427]

Since I bought the place the system has always been like this. was an ex-rental property. Had real problems with flow when 1st moved in. Had never been properly maintained with an inhibitor.

Sytem pipework is 22mm flow and return down into 8mm micobore for the flow and return legs.

But surely if the overheat stats and high and low stats were overridden, and boiler still cuts out, this would not be a flow problem?

 

[StevenJames125]

ok have you chedk the fan (spinning freely) - resistance of the windings? air pressure switch - working ok/tubes not kinked at all / flue clear / venturi fully clear etc?

what's the ignition lead like? electrode itself? rectification probe all ok not dirty/misaligned etc?

check everything

does the pump require a perm live for any overun feature to work properley?

 

[twgas]

I have err bypassed the overheat cut out and high and low thermostats on the pretence that it maybe a flow problem and timed the boiler on fire up but it still cuts out after 10 minutes.

If you by-passed the stats (totally stupid!) it wouldn't prove anything about circulation. IF what you say is true, you need a RGI.

 

[StevenJames125]

if the gas valve is modulating - check the operation of the modulatuing solenoid too. check every component

 

[AC427]

My quote was wrong. I was meaning if they were by-passed. But I have taken onboard your comment and will seek out an RGI