Ideal isar he30 faulty

[quorntobewild]

So our trusty ideal isar boiler has started playing up.
Tap hot water going to rads was first so cleaned out diverted valve lots of bits of crap fell out, like rusty lime scale..
Then thd tap hot water came on hot then went cold, checked the control thermister ok the console return ok the overheat one is at about 4000 ohms but I'm not sure what it should be at, had L-F error and L-9.
Now 0 with 3 lines.
So I'm not sure if the diverted valve is the problem or the overheat sponsor or something else.
All help is very welcome.
Thanx

 

[shambolic]

Kill it with fire. Or change plate hex if only a problem on hw.

 

[MTCH]

Did you run the Heating before trying the Hot water again?

 

[quorntobewild]

@shambolic
Seals went on hex month or so ago, are you saying it may be blocked, it dosnt seem blocked in fact it looked pretty good.

 

[quorntobewild]

@MTCH
So put heating on seems ok
Ran hot water came out got 15 secs then cold 15 secs then hottest and best it's been constantly scolding running slow hot running fast.
No faults now we left it off all night...

 

[quorntobewild]

Just to note is a He30 and the pcb paperwork says secondary control box links should be on 2 for combi but there's no link present.
Not sure if this means any thing or is important lol.

 

[quorntobewild]

Now it seems to be working fine lol OMG.
Noticed burner light is staying on now when hot water demand and wasn't before.

 

[MeldrewsMate]

Am I alone is struggling to understand you?
Please try to use standard English, or at least something close to it.

 

[quorntobewild]

I'm not sure which bits are hard to understand.
The hot water has been running hot then running cold.
A few days a ago when we ran the hot tap we noticed the radiators were getting hot and we were getting no hot water out of the tap.
I cleaned out the diverted valve and checked that it was not stuck.
I checked the temp sensors, which seemed fine.
The overheat sensor read 4000ohm and I do not know if this is a correct reading.
The flame sensor wire had perished and had bare areas so I replaced the wire.
The heat exchanger seals went a month or so ago, so I replaced them and the heat exchanger seemed in good condition.
At present the heating and water are working fine, we have the hottest water we have ever had and lots of it.
@MeldrewsMate
Sorry if my previous were not clear.
Many thanx

 

[quorntobewild]

So has replacing the wire and resetting the boiler cured the issue.
Who knows.....
Thanks for help and advice.

 

[MeldrewsMate]

I'm not sure which bits are hard to understand.
The hot water has been running hot then running cold.
A few days a ago when we ran the hot tap we noticed the radiators were getting hot and we were getting no hot water out of the tap.
I cleaned out the diverted valve and checked that it was not stuck.

The hot/cold/hot cycling of the DHW could have been down to a combination of a lack of heat transfer from the boiler water to the DHW and a faulty flame sensing probe, consequently the boiler water heats rapidly, causing the flame to be (correctly) extinguished. Once the boiler water cooled to the trigger level the flame would be re-ignighted, but if the flame sensor did not 'see' the flame the PCB would go through another ignition cycle. The consequence is DHW that goes hot/cold/hot/cold...., etc.

The replacement of the flame sensing probe, and its restoration to full working order, would enable the boiler to re-establish the flame with less delay, maybe avoiding the temperature cycling you described. Coming back to my first point, it takes very little scale build-up to greatly reduce the effectiveness of a plate heat exchanger, so if the DHW temperature falls significantly from the spec value at full rate (14 litre/min from memory) I would suggest descaling the secondary side of the plate heat exchanger. This can be easily done in situ with a powerflushing machine on the cold inlet and hot outlet.

Your last two posts were very clear.
MM