HELP, IDEAL EVO HE, FLASHING H3 CODE

[pen4uk]

Hi, I have a Ideal Evo He combi, first problem code came up was FL. And was told by my local plumber yes mate thats expensive it'll be ya condence pipe needs replacing plus its a good chance your pump needs replacing,etc etc. I came on this site and was told all that will be is your spark plug ends {electrodes} have got hot and bent, yes yes spot on saved a fortune thanks DIY NOT. Well now a code H3 is flashing.And its not working at all. And been told your PCB board needs replacing the cost is around 200 pounds is this rite?? is this yet more bull? if true is there anyway or cheaper way round this HELP PLEASE

Regards Colin

 

[Andygasman2010]

H3 is DHW sensor fault. It's got two black wires and can be tested if you if you have a multimeter.

Post back if you need instructions on how to.

 

[pen4uk]

Hiya, thanks for your fast reply, yes please if you could help me through DHW sensor black wires would be great. Thanks again

Regards Colin {pen4uk}

 

[Andygasman2010]

You need to check the resistance through the sensor, it should be about 10Kohms@25C. If you're unsure how to check this you should probs get someone in.

 

[pen4uk]

Thanks again could you tell where or what it looks like, plus is it best to replace the sensor?

 

[Andygasman2010]

It's accessed underneath the boiler i think, under a white cover plate. make sure it's not been unplugged accidentally. It's best to change the sensor if the sensor is broken...

 

[pen4uk]

Well i dont no what to say now, Just got home from work and the boiler now is going full bore, Very odd all the Rads are red hot the house is subtropical. But the central heatings not even turn on, The steam coming out of the flu looks a little brownish. Have i got something major going wrong?


Regards Colin

 

[gas4you]

Sensor/ntc is in a wet pocket, so isolate cold water inlet first.

 

[Andygasman2010]

Sounds like it dropoped out of range briefly, maybe a got a little wet or something.

Brown steam out of the flue?! strange...

 

[DrEvil]

Hi, I have the same problem on my boiler - Ideal EVO C22-35 (previous owner had it installed - can't wait to get it changed!) come on last night.

Cold water wouldn't work for a bit. Went and looked at the boiler and was saying H3. Looked up in the book and this said it was the DHW thermistor issue. Suggestions were to test the resistance to identify if it is an issue with the thermistor or possibly the PCB. My multimeter is at my dads at the mo, but I can get it back at the weekend so can't test it until then.

However, the PCB and the fan were changed in April when the last fault occured (I only moved in in March!); so am thinking this is very likely the DHW Thermistor.

In any case, switched off the boiler and on and the code flashed for a little while, but then it seemed to clear itself and the hot water started working again.

Now the water supply has been funny since we moved in as when you start the hot water on the shower it tends to warm up quickly, run hot for a minute, then go cold for 20-30 seconds, then go hot again. I am wondering if this was linked all along.

Knowing that winter is fast approaching I am a little concerned and thought I would just quickly check if the DHW thermistor is an easy replacement and possible to DIY. I think the relevant part is this one .

Given the part looks quite simple, am I reight in assuming this looks like it should be an easy change? I'm not boiler technician, but perfectly capable of doing simple jobs - and similarly happy to understand if something is beyond my scope, but would I be right in guessing the process is:

- switch off boiler
- it is in a wet location so switch off the water supply, running out the hot and cold taps to get the water out,
- un plug cable, remove retaining clip, pull out old thermistor
- push in new thermistor (should I silicon grease the o ring), put in new retainer clip and plug in cable
- restart water supply
- restart boiler

All feedback appreciated!

 

[DrEvil]

Actually found the manual on line, and yes looks as easy asI thought. Seems to be a simple knurled retaining nut which holds it in place, should be able to unscrew the nut plug in the new one and fingers crossed!!

 

[shambolic]

Actually found the manual on line, and yes looks as easy asI thought. Seems to be a simple knurled retaining nut which holds it in place, should be able to unscrew the nut plug in the new one and fingers crossed!!

Nope not a nut it's push fit with a pin holding it in.
It's a knurled nut on an esprit not the evo or isar

 

[DrEvil]

Ok, ta, will take a closer look at it when home later. The online evo manual seemed to suggest a knurled nut, but it absolutely wouldn't suprise me if that was for a different boiler.

Thanks for the heads up!