what a surprise! problems with a ideal isar

[Kmort78]

Hello people this is my first post.Have been asked to help a customer with a ideal isar he 24 , I am a GSR engineer but have on the main only worked on install,so am a bit green on fault finding!!Before christmas the boiler had a pcb,new gas valve,condense trap clean,and spark electrode fitted by another engineer who can not be contacted!!! When i arrived the boiler would not run,I cleaned the syphon and heat exchanger which was blocked.Now the boiler will run on hign demand ,dhw on full as with ch, as soon as the dhw is turned off or reduced,and the fan speed slows.The boiler starts to vibrate and you get the whoop fog horn noise as if there is to much air to gas ratio?? but only happens on low demand,can the gas valve be ajusted,anyone know what is the cause..

 

[fixter1]

have you fga it to see what readings you are getting

 

[gasmarc]

Sorry mate I would call Ideal , some of those ideal boilers are a nightmare ,good luck

 

[cwrplumbing]

Hi there this sound might be a re virberation noise, check your flue seal especialy if its a vertical flue. The gas valve is not adjustable !! as this has been replaced check the white tube from the gas valve to the case see if its blocked. if you know how to check the offset reading on the gas valve your looking for a reading of -1 mbar when the fan is pulling.
This realy sounds like a flue seal to me though.

Good luck.

 

[Kmort78]

Cheers for advice!, i will be returning to look at the boiler tomorrow,I did check the white tube from gas valve last time i was there, i was under the impression this activated the solinoid on low fire mode??!,I am going to check the valve as i didn't replace,lots of graphite on bottom of case,not a vertical flue but thanks 4 the tip will check flue seal tomorrow.

 

[Kmort78]

Sorry!! what do you mean by fga,

 

[AllyBongo]

flue gas analyse

 

[Kmort78]

flue gas analyse of course!!! Yes have checked this after cleaning heat exchanger,all well within the normal expected readings ,cheers

 

[RoryD]

Although the condensate has been changed, I would double check, a few engineers went to a call for similar, It went after changing the condensate trap. It is also very important to check the metal brackets in the heat exchanger "coathangers" as we call them. The hold the insulation in place, there is a manufacturers fix / upgrade for these.
But back to the condensate trap, ensure it is clean, and check the sump has been cleared of clinker

 

[Kmort78]

I did get a lot out of sump and condensate trap,even though it had been cleaned,cleaned and checked again after i cleaned heat exchanger!,This was ment to be cleaned( or checked) 2 weeks ago on a previous service,coathangers seem fine and insulation in good con,going back to check the gas valve,and flue seal tomorrow,cheers for advice

 

[Amir Akhtar]

had a few problems with pumps on those

 

[Kmort78]

I think there are problems with every part within the Ideal isar!! Hope the new logic + range are better as i have fitted a few in last couple of months!!

 

[Kmort78]

When i fga there was 46% xces air ,removed gas valve,that had been changed,lots of graphite on inlet cleaned and reinstalled boiler runs for hour and half then fog horns,locks out and flashes the L F code ,the valve can be reset by putting pressure on the 6mm white tube,I think the gas valve is not working on low fire !! anyone else have any idears

 

[quality]

Lf can be condensate drain, flame detection probe. ignition electrode , ignition coil , ignition lead , PCB (unlikely) or as suggested gasket in the flue which could explain the noise at low rate

 

[Billy Bob Bob]

when you serviced it i take it you used a gasket service kit?

 

[Kmort78]

Cheers have checked those,far to much air for stable combustion all seals are fine,washed con drain out cleaned heat ex,checked standing working pressures, Most engineers i have spoke to about the prob said gas valve,flue,con drain,good luck!! The ideal isar has a small fan club.

 

[Kmort78]

I didn't service the boiler another engineer did!! he changed the gas valve ( he says) I am hoping that he replaced the gasket when he cleaned the heat exchanger,It looked new and was in good con,but the exchanger was a bit dirty,mainly underside fins above sump which were clogged,Are saying the gasket could be letting by,how could this be causing the problem?????

 

[Billy Bob Bob]

flue,fan or heat exchanger gasket's will cause this sort of problem if damaged

 

[Kmort78]

They all seem be fine ,dont think any are letting by.cheers

 

[Kmort78]

Changed the gas valve today, and the boiler is running like a well oiled machine,The other gas engineer had charged 4 a service and new gas valve, and done none of the above , Cheers 4 the posts