Ideal isar HE 24 Banging

[Graham HTG]

I have been to an Ideal isar HE 24 which is banging and locking out. I listened to continuous run of fault from customer about this boiler which was from wormfront. I am familiar with the isar and some of the problems but this one has got me stumped, any HTG engineers advice greatly appreciated. Now to the story, Firstly tested boiler on dhw preheat, worked ok, ran the dhw and boiler started to bang after a short time, ran boiler on htg and againe boiler stared to bang.
Noticed spiro fiter on the flow from the boiler which made me think there could be a blockage. First of all I checked the pump it was running took it off and check pump impeller all looked ok. I then took filter from flow washed it out and fitted it in the return, well boiler drained I flushed boiler back through the flow and return with diverter valve and pump on and off, as far as I can see it all seem clear, I also changed boiler flow thermister and it still bangs.
Engineers please HELP ME this one seams to have be beat.

 

[cjg]

blocked heat exchanger ???? low flow through? checked by pass, just a couple more points to look at, chris,

 

[Dannypipe]

Graham, I've had the exact same issue on the exact same boiler, twice. There's a newish delevopement near me and the all have Ideal HE24's. I've had the problem and solved it twice.

I phoned manufacturer who gave me two possible reasons.

1/ Spark electrode needed changing as it was producing a weak spark and letting the gas build up therefore explosive ignition.
2/ At peak times the gas pressure drops and this could result in explosive ignition.

Anyway, it wasn't number 2. Its a medium pressure estate and the supply is perfect.

So I changed the spark electrode, and job done. These boilers tend to get left as the MI state that to service you just combustion anaylise and gas rate check. if the results are OK you don't take the case off. Therefore a lot of engineers stick slavishly to this rule and the insides never get checked/cleaned properly. I personally think this is wrong. If I put my car in for a service and the mechanic checked the exaust fumes and never opened the bonnet, I'd be very disatisfied. However the amount of people who say 'oh you're taking the cover off' when I service boilers makes me realise that it's perfectly normal to do the bare minimum.

Ignition electrode kit - part number = 173528
IDEAL - parts order number : 01482 498665

I hope this info helps.

Also check/clean the condensate, sump and trap.

 

[cjg]

hi danny your spot on with;1/ Spark electrode needed changing as it was producing a weak spark and letting the gas build up therefore explosive ignition.
2/ At peak times the gas pressure drops and this could result in explosive ignition.

but i think the problem is in the heat ex, or bypass set to high, or combo of the two, ;; HD cleaner in on low temp, run for 4/5 days may also help?

i"ve seen bent electrode thats been 6/8mm at lest out at end and been firing acoss half way down!!

anyway let us know how you get on Graham,

 

[Graham HTG]

The banging my not have be the best word to explain , Its more of a cracking / banging sound and the pressure gauge fluctuates (does not go over pressure though).
After all I have done it still sound as if theirs a blockage or the pump is running slow.
I was hoping someone has had the same problem. Ringing technical again this morning.
Thank you all for your input, keep it coming, I'll give you an update later.

 

[cjg]

awaiting with baited breath,(LOL) still think same at mo, regards chris,

 

[Graham HTG]

Sorry cjg Ideal technical say I’m right on the mark heat exchanger blocked. I’m still think this sound a bit odd that this type of heat exchanger could be blocked. I’m going to put some sentinel x800 in the system and have it run on a low temperature for 2 or 3 days then go back and power flush it out. I’ll be back and let you all now what happens.

 

[cjg]

hi G, first post
blocked heat exchanger ???? low flow through? checked by pass, just a couple more points to look at, chris,

not far off!!!! (LOL) glad you sorted, regards chris

 

[buckley plumb]

i had one once that banged intermittently mainly on full rate(icos ) but same insides. it gas analysed ok and seemed ok when i inspected burner .i eventualy found the condensing heat exchanger blocked and it had built up into the flue causing a restriction .how the analyser reading was ok i will never know .there is no way of cleaning it without removing flow and rtn pipes .it was blocked with what looked like grey corn flakes .this particular boiler was working very hard running uf and rads.
other problems i found have been poor pumps / burner chamber insulation falling out onto heat exchanger there is a mod kit for this

ant

 

[Graham HTG]

Sorry Chris I mist your first posting.
Just to keep you all up to date, Thursday morning tried new pump and there was no deference.
I checked the flow through the boiler and heating system again with the mains water and it all looked to be clear no blockage. Now added Sentinel X800 to system and asked customer to run boiler on low temperature. If time today I'll power flush it through the pump housing.
I daunt feel confident this is going to work.

 

[cjg]

did you take the heat exchanger out and check it,

 

[Graham HTG]

Flushed x800 out with all rads fully open, system clean no muck at all.
Just seen your post cjg and I haven took the heat exchanger out.
If I take the heat exchanger out what might I find.

 

[cjg]

hi G, well is it running ok now its been flushed, why i asked about the h/e unit was these some times get blocked and restrict the flow through hence you can get the problem, a good flushing sometimes clears them, regards
chris.

 

[Graham HTG]

Boiler still the same that why I asked what you find inside

 

[md68]

Have cleaned out the condensate sump? I've had this problem a few times on this model boiler and it's always turned out to be a blocked sump