Ideal Icos HE 3080

[SteveSPS]

I have had one of these boilers fitted for about 5 years. Last year my CH system started banging when the boiler shuts off. It is fitted to a fully pumped vented system and was initially installed at the same time as my old gravity system was converted to fully pumped. The installers did not fit a bypass in the system and until recently this was not a problem. When the banging started I fitted a bypass in the form of a gate valve but have changed this to a proper bypass valve. However the banging goes on each time the boiler shuts off. I am surprised that the boiler manual makes no mention of a pump over run; it is possible build in a pump over run even though the boiler does not include a facility for one?
I clean / flush / inhibit my system annually and can find no other reason why it should bang on shut off; it seems the obvious cause is the pump shutting off preventing continued circulation of the very hot water in the boiler heat exchanger.

 

[DP]

How do you clean and flush the system? What inhibitor are you using.

I dosed a system with a well known inhibitor. Boiler started to behave in a similar manner. I found the system water was like cough mixture. System was chemically cleansed and treated with Sentinel X100. Still purring away.

 

[gas4you]

The boiler does in fact have a built in pump over run. This is occuring when the flame light has gone to flashing instead of constant on.

The sequence is slow flash pump on boiler either up to temp or starting a cycle, quick flash ignition sequence, constant light burner alight.

iff your system is in fact very clean and your auto btpass set up correctly I would suspect the pcb faulting. A very common fault with these and very expensive

 

[SteveSPS]

I use Sentinel products to clean / inhibit. G4U can you tell me where you found the info on the pump overrun as I'd like to carry out some fault diagnosis, thanks?

NB Just had a look at the pictoral and functional flow diagrams in the manual and there are is no indication of the boiler being connected to the pcb which I would have thought was required if the boiler was to control the pump over run as opposed to being controlled via the central heating controls.

 

[nortimax]

Why do you clean and flush annually?

 

[gas4you]

I assumed it was standard knowledge, although I have been on the Ideal factory training course. I wouldn't recommend trying to open pcb case. They are designed to just replace!

 

[meldrew's_mate]

...The boiler does in fact have a built in pump over run. This is occuring when the flame light has gone to flashing instead of constant on....

Nope, neither the original m3080 nor the later HE24 (and derivatives) had or have any sort of pump overrun. In my opinion this was an oversight, but I suppose they thought the low operating temperatures would make this unneccessary.

...If your system is in fact very clean and your auto bypass set up correctly I would suspect the pcb faulting. A very common fault with these and very expensive

As above, if it doesn't have the pump overrun, you won't mend it by replacing the PCB.

I have had one of these boilers in my house since early 2003, fitted to a clean system, with X100 inhibitor. It has never been dismantled, serviced, or had any invasive surgery, just an occasional check with a flue gas analyser; and it had performed faultlessly.

I hear lots of stories of icos' unreliability, but I've fitted plenty of these over the years with only about three failures; one on an icos and two on isars. The common factor appears to be incorrect set-up. On the icos the customer had had the builders in who promptly drained the system, inserted copious quantities of flux, debris, and a leak, then left the system unbalanced. The common symptom was a boiler which short cycled and caused an excessive number of ignition starts per hour
The isars (combination boiler) just had lots of starts because they're combis!

Nortimax asked a relevant question, just why do you drain and flush evry year? In a properly designed (not pumping over), dosed, and leak free system once every Preston Guild should be enough - just check the inhibitor concentration every couple of years with a Sentinal test kit.

So get your system balanced properly, and don't have the boiler temperature dial at maximum. It might be worth checking your pump performance too.

 

[gas4you]

Are you sure. Ones I go to the pump keeps running after all call for heat has stopped. Maybe not classed as an official 'over run' but it still keeps pump going.

 

[SteveSPS]

Why do you clean and flush annually?

Why not?, my CH system is micro bore. I dont want it sludging up; it's not like it's a difficult job.
My rads get hot and with a 4 bedroom house I think it would soon become apparent if the pump was on the way out.
My boiler stat is set about half way, I've never run it at full.

Bearing in mind the above suggestions, back to my original question...is it possible to wire in a pump over run, extractor fans have a device for allowing the fan to run after being switched off; is something similar available to use to control the pump?

 

[nickso]

Bearing in mind the above suggestions, back to my original question...is it possible to wire in a pump over run, extractor fans have a device for allowing the fan to run after being switched off; is something similar available to use to control the pump?

no and even if there was you are not addressing the real problem and you are circumventing the MI's....however good or bad they are.

if i were you i would be re-reading the MI's from the start and make sure nothing else daft has been done before you start to go on an ill informed jury rigging experiment with your boiler.

 

[SteveSPS]

if i were you i would be re-reading the MI's from the start and make sure nothing else daft has been done before you start to go on an ill informed jury rigging experiment with your boiler

Hmm interesting...I have read the MI's more times than I care to mention and considering that most boilers have a pump over run I wouldn't consider it ill informed or jury rigging.
But hey thanks for your input anyway.

 

[nickso]

if i were you i would be re-reading the MI's from the start and make sure nothing else daft has been done before you start to go on an ill informed jury rigging experiment with your boiler

Hmm interesting...I have read the MI's more times than I care to mention and considering that most boilers have a pump over run I wouldn't consider it ill informed or jury rigging.
But hey thanks for your input anyway.

well if this boiler doesnt have a pump overrun and you rewire it to have one......is that not "jury rigging"? ......certainly not what the manufacturers had in mind.

only trying to help mate

but hey thanks for your reply anyway

 

[Rob]

if i were you i would be re-reading the MI's from the start and make sure nothing else daft has been done before you start to go on an ill informed jury rigging experiment with your boiler

Hmm interesting...I have read the MI's more times than I care to mention and considering that most boilers have a pump over run

Maybe you should get on to Ideal about this then, seeing as you know whats best. Oh wait flushing your system every year, you probably dont and may be doing more harm than good.

 

[gas4you]

Nope, neither the original m3080 nor the later HE24 (and derivatives) had or have any sort of pump overrun. In my opinion this was an oversight, but I suppose they thought the low operating temperatures would make this unneccessary

I have just checked the Ideal training manual and I was in fact incorrect. meldrews mate is correct in that the open vented version does not have a pump overrun, but the M3080 system DOES have a pump overrun for 5 mins.

The Isar however also has a pump overrun for 5 mins after heating cycle and 5 secs afte DHW cycle.

Aplogies to meldrews mate, it was my fault for not reading op correctly

All the ones I visit (that i have installed) were the system or Isar version.