Icos HE 24 system L9 error intermitent

[Plumb Ugly]

Yeah iv tried to follow the flow chart and check everything it suggests but haven't been able to find any problems it all appears to be perfect until it throws (he fault code up which iv never seen it do! Changed the dry fire stat more to rule it out than anything I'm wondering if the pump is sticking

 

[AMGasServices]

Put a cloth under the pump open the big silver screw (on the pump) put a Philips screwdriver inside it and put force on it. If you can stop it then the pump is on its way out.

 

[Plumb Ugly]

Already done I'm afraid fella plus I measured the resistance across its terminals and took temp diffs from the flow and return and the only thing is the resistance figure was a bit on the high side 295 ohms Ideal said it shouldn't be higher than 300. Hmmmmm

 

[AMGasServices]

Try loosening the auto air vent to make sure there is no air in the system. I can recall going to a job showing L9 changed thermistor, pump and removed air from the system it would run for 1 min and then back to the same fault eventually I ended up changing the boiler. Because I thought the heater exchange has something stuck in it. Try cleaning the system.

 

[Plumb Ugly]

I'm wondering if the heat exchanger might be giving trouble too

 

[zeebeedee]

Im having a very similar issue at the moment. Pump changed/flushed by previous engineer. Im thinking the heat exchanger is buggered! I've heard the flow/return can pin hole on these causing it to overheat.

 

[Plumb Ugly]

Brilliant! I really am thinking that there may be a problem like that as an under performing pump should show up when I did the flow and returm temp diffs and if it was sticking I doubt very much that the pump would free itself off without a helping hand! I'll have to speak to the owner and see what they want to do because I can't see the new pump curing it but I have been wrong before...

 

[zeebeedee]

Recharged the expansion vessel on this yesterday afternoon as it was missed on the previous visit. Think there may have been air trapped in the heat exchanger. I opened the drain cock and pumped up the expansion which seem to push it out. So far so good, only lasted a few hours at most after the previous engineer visits.

 

[Plumb Ugly]

New pump lads! Been fitted over a week now and no sign of L9 thank fully