Need a Plumbers advice...

So let me get this right..Youve set your multimeter to read 200Ω when you need a scale to read over 10,000Ω?

Mick

Edit: try the 20K scale :)
 
Well that looks like a faulty sensor then, cos you should be reading over 10kΩ, esp as the temp is lower than 25C :)

Mick

Edit: Just a thought, but are you sure the 'plumber' swapped the DHW sensor/thermistor? And not one of the others by mistake..
 
FlyingFish said:
Well that looks like a faulty sensor then, cos you should be reading over 10kΩ, esp as the temp is lower than 25C :)

Mick

Edit: Just a thought, but are you sure the 'plumber' swapped the DHW sensor/thermistor? And not one of the others by mistake..
Click to expand...

Ah OK mate, thanks. Well, he said he changed it, but I've no way of proving it as I didn't like to watch.

When I look that part up in the book,there are two different part numbers:

DHW Thermistor - Wilo *
DHW Thermistor - CP*

What is Wilo and CP? How do I know which one my boiler is?

As soon as I know which one it is, I'll get one ordered and replace it. Looks like I've got to isolate the water and drain the boiler to do it.
 
You dont really need to 'drain' the boiler as such, but turn the cold water inlet valve off under the boiler at the back. Open a hot tap, to release the pressure, and if you have any taps lower than the boiler then leave them open to drain the legs of water.

Stick a bucket/bowl under the boiler to catch a couple of pints(max) of water, and then remove the sensor...Take it for a walk down to Parts Center, and they might be kind enough to sell you the part you need, take the book if you need to, and jot down the serial no. from your boiler just in case they need it.

Be warned tho, you are doing this off your own back and responsible for your own actions! That includes listening to myself or anyone else on here ;) Its the risk you take doing it yourself to save some money rather than getting a professional in. Potentially it can be a more expensive road to go down, as I'm sure you are starting to realise.. With no training, experiance or qualifications in what your doing, things can easily not go how you would like or imagine.. But saying that....hope it goes well for you :)

Mick
 
Thanks for your help Mick :)

I would have used a professional if they didn't constantly let me down on appointments or forget to ring me back! I'm obviously not saying all are bad. I realized this with cars from a young age and have always done everything myself on mine.

I'll change the sensor and go from there. If that doesn't fix it then I'll potentially take out a boiler insurance and make a claim (providing there is no 30 day clause).
 
How you getting on with your boiler?

I got called out today to an Ideal HE combi reportedly showing the H3 fault code...So took a dhw sensor with me, and fitted it, all worked fine :)

Measured the resistance and took a photo for you:

IMAG0263_zpsb2de6e0b.jpg


Mick
 
Hi Mick!

Thanks for replying, that's very kind of you. I've only just seen this reply :)

Well your suspicions were correct, the DHW Thermistor was the faulty item. I fitted the new one tonight and the boiler straight away lit. GOOD NEWS! Wasn't too difficult to do either. Goes to show my plumber wasn't truthful with me!

Only problem is, my original fault is still there. Central heating is absolutely fine. It stays lit and all radiators are piping hot. The hot water on the other hand isn't working properly.

With the hot water tap on slowly, hot water comes out. With the hot water on at a fast rate/flow, there is a small amount of heat in the water for a few seconds and then it goes cold again. Looking in the manual and on Google, it seems my fault could be the Diverter valve? Would you say the same?

My boiler has the CP Waterset. Is it a difficult job to replace this valve?

Thanks again :)
 
Hi Matt, glad the H3 fault is sorted now :) Shame you got the run around from your plumber and had to fork out for a PCB without needing it! :(

Simple method to test the diverter valve is to start with the heating system cold, and the boiler off. Turn the boiler on, with no demand on it. It should fire up and preheat the plate to plate, then stop and go into standby.

While its doing this, check by holding onto the heating FLOW pipe under the boiler that its staying cool, preferably hold it a foot or so below the boiler, to be clear of heat conduction. Look in the manual to identify the correct pipe.

If this is cool, and hasnt heated up then run the hot tap. The boiler should fire up with the demand. Hold the pipe again and check to make sure the heat is not escaping into the heating circuit. If it is you need to look at the diverter motor, or hydrualic cartridge as being faulty.

If the pipe stays cool but the burner stops burning gas, even though the tap is still running then you could have sludge in the plate to plate heat exchanger.

Mick
 
FlyingFish said:
Hi Matt, glad the H3 fault is sorted now :) Shame you got the run around from your plumber and had to fork out for a PCB without needing it! :(
Click to expand...

Indeed, I initially tried it with my PCB and it fired up without issue. Oddly though the Reset button still isn't doing anything. I could try one of my other PCB's before sending back, if not I'm guessing this will need the display panel looking at or replacing.

Simple method to test the diverter valve is to start with the heating system cold, and the boiler off. Turn the boiler on, with no demand on it. It should fire up and preheat the plate to plate, then stop and go into standby.

While its doing this, check by holding onto the heating FLOW pipe under the boiler that its staying cool, preferably hold it a foot or so below the boiler, to be clear of heat conduction. Look in the manual to identify the correct pipe.

If this is cool, and hasnt heated up then run the hot tap. The boiler should fire up with the demand. Hold the pipe again and check to make sure the heat is not escaping into the heating circuit. If it is you need to look at the diverter motor, or hydrualic cartridge as being faulty.

If the pipe stays cool but the burner stops burning gas, even though the tap is still running then you could have sludge in the plate to plate heat exchanger.

Mick
Click to expand...

heating FLOW pipe, do you mean the CH Flow pipe? This is the pipe with the pressure gauge on it which I topped up to 1.5 Bar?

Sounds straight forward, the pipe feels a bit warm at the moment as I've had the heating on. I'll let it cool down and then try this.

TBH before I turned the heating on I was playing about with the taps, and the boiler always shows 'd' whilst a hot water tap is on. If I turned it on fast flow I did notice the blue light on burner went out, so it could be sludge in the plate to plate heat exchanger. I wont know until I can do your test though. In either case is that a difficult job to do?
 
I doubt if the PCB is smart enough to figure out if the diverter motor or cartridge is faulty, by using its temp sensors. So in either case no fault code would appear. You would just have the heat escaping down the CH flow pipe.

Have a read in the manual to see if swapping either, orr the plate heat exchanger is somehing you want to tackle.

Motor is easy, plug n play.
Cartridge, boiler CH drain down and swap the cartridge. Taking care of course.
Plate to plate heat exchanger, full draindown of CH and DHW water, four new seals, back flushing the heat exchanger, and soaking over night in DS3, or fitting a new one.

Mick
 
Hi Mick,

Well I called Ideal for advice and they are pretty sure the issue is a blocked heat exchanger. They said it's best to replace it but no doubt that is a MASSIVELY expensive part?

Alternative is to remove and clean as you suggested above. Have you done this before? I'm guessing you need to compeletely remove it to clean it out?
 
The cost of the heat exchanger can vary wildly from one manufacturer to another, cheapest Ive come across is Baxi, dont know off hand about Ideal.

Cleaning or replace, either way the boiler has to be isolated from the gas/water/electric and drained of all water (DHW & CH).

After that two screws and its out, it is always a good idea to replace the four seals, because two hold mains pressure, and the other two are usually crapped up with CH deposits.

Once its out cleaning can either be back flushing with a hose pipe, for this you need to figure out which ports are the flow and return. Or soaking and washing over night with DS3 (chemical metal cleaner) And yes I have done both. Other option is to replace the heat exchanger for new.

Which ever you do, if sludge is the reason for your poor DHW, then you need to do something about the underlying problem or it will only happen again. Think about fitting a Magnaclean (filter) to the return pipe.

Mick
 
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