Ideal Icos HE24 not responding to demand?

[ChrisF1874]

Hello helpful people of DIYnot It's getting a bit colder so my heating is playing up.

A ten year old Ideal Icos HE24 sits stubbornly showing status 0. The switched live (L2) has volts on it - indicating demand? - but it doesn't do anything. Am I right in thinking this indicates a boiler fault? If I switch the controller off, the voltage on L2 goes away.

In the last couple of days, it has fired up a couple of times and the heating has worked for 10 or 15 mins but then it shuts off and won't go again.

Any tips on how to diagnose the boiler fault would be greatly appreciated!

 

[45yearsagasman]

Your installation instructions will have a step by step fault finding chart. You'll need a multimeter and some skills to ID the fault. Just do the basics and leave the rest to a professional. There is really not a lot a diyer can do with that boiler. It could be many things causing your boiler not to start. Voltage present does indicate a boiler fault.

 

[ChrisF1874]

Thanks for the reply. The fault finding guide only covers fault codes and my boiler isn't showing any fault codes.

I've fixed it myself when I had fault codes in the past - replaced the flame sensor wire that had lost its insulation and was shorting to the case - remade the connections to the control panel PCB that had moisture damage.

Problem is that I've got no fault codes so was wondering if anyone had experience where an Icos would ignore a demand signal without showing a fault.

 

[Agile]

You should not really be opening the case to your room sealed boiler as a DIYer.

Obviously its an electrical problem and that's not the most friendly of boilers to work on. Not helped by the propensity to leak!

Get a professional. Or a fixed price repair from Ideal or BG.

Tony

 

[ChrisF1874]

Thanks for the advice. The problems I had five years ago were caused by a leak but it's as dry as a bone now.

I probably will get a pro in if I can't make any progress myself this weekend. I've got a spare control PCB as it happens, bought for me by the last pro I had in to fix it when it was showing an LE (PCB error) code. Only there was nothing wrong with the control PCB, it was a corroded connector PCB

Just wondering if anyone had seen this sort of behaviour before - Icos ignoring demand signal but not showing a fault.

 

[picasso]

When you say voltage what voltage are you getting exactly ? you could try linking out L1 and L2 and see if the boiler fires.

 

[ChrisF1874]

Just testing with a mains tester screw driver. That's a very interesting suggestion on the basis that it's now looking like an intermittent problem (it seems to fire up every now and then). Thanks, I'll give it a go.

 

[Echo the husky]

Just testing with a mains tester screw driver.

Don't rely on that as proof there is a switched live to the boiler. Either use a proper 2 wire tester or put a link between L1+L2 as Picasso says.

 

[ChrisF1874]

Picasso/Freddo - Super job. Boiler fires up fine with L1/L2 linked so it's not a boiler problem. Thanks very much. I'll be back when I've tracked down the root cause.
Unfortunately, my system was upgraded to the current boiler by "professionals" in 2006 and the wiring is an utter pigs ear.

 

[Echo the husky]

Is it an S plan or Y plan? (Or one of the the other less used plans?)

 

[ChrisF1874]

I dunno yet. I've got a box in the airing cupboard with a bunch of choc blocks, various old wire ends, sellotape and knots as strain relief.
I've told the wife I'll leave it alone for an hour or two with L1/L2 linked whilst the house warms up ... and I can watch some football.

 

[Agile]

A neon screwdriver is a quick way to see if you might get a shock but not anything a professional would find very useful.

Tony

 

[ChrisF1874]

A neon screwdriver is a quick way to see if you might get a shock but not anything a professional would find very useful.

Touche

 

[DP]

A neon screwdriver is a quick way to see if you might get a shock but not anything a professional would find very useful.

Tony

I do and consider my self a professional. In fact have two neon drivers in the bag in case one goes missing.

 

[ChrisF1874]

I do and consider my self a professional. In fact have two neon drivers in the bag in case one goes missing.

DP, don't trust them for checking a switched live connection because they lie.

Is it an S plan or Y plan? (Or one of the the other less used plans?)

Mine's an S Plan. Current theory is that the CH valve actuator's relay is duff and the 'intermittency' is when the HW thermostat switches in providing the demand for the boiler.
I've got the tools to find out tomorrow. Urgency is lower now the house is toasty again.