Valiant ecotec Pro F.73

[mwildin1]

Hi,
I have been having an issue with my valiant boiler which is approx. 4 years old. Last week I got the F.73 fault (water pressure sensor) but the manometer read 1.5 bar and the EV seemed to be correct pressure. I read on these forums that sometimes cleaning the pressure sensor would cure this. I removed and cleaned the sensor and all seemed fine.

However, two days later I had the same F.73 fault again so I tried cleaning the sensor again. This time it didn’t work (I think the first time may have been coincidence). I also found that when I pressed the ‘-‘ button I had no pressure reading at all, the screen just displayed ‘–bar’.
I thought that the sensor could be U/S and ordered a replacement. However, I just fitted it and still get the same error. When I press the reset button (flame with cross) the fault light goes off for a few seconds and I hear something turning, but I’m assuming that the pressure fault stops any further operation.

I just wondered, is there something I can check when I get the ‘-bar’ reading on the display. Have I missed something when refilling the system with water?

Any information would be appreciated before I call out an engineer. Thanks in advance.

 

[mwildin1]

This is the -bar display when I press the - button.

Untitled

• mwildin1
• 6 Mar 2012
• 1

 

[lightning]

For the price of part change it, if its the salmon coloured one.

 

[Agile]

For the price of part change it, if its the salmon coloured one.

I think that he has ordered and fitted a black replacement.

But I dont think he has cleaned the communication drilling.

Tony

 

[mwildin1]

Hi, thanks for the response. I have already replaced the water pressure sensor.

What is the 'communication drilling'?

 

[mwildin1]

I replaced the old black sensor 0020016532 with a new black one 0020014190. I read that this was the replacement part for the old Glow worm part.

 

[mwildin1]

I've just metered accross the green signal return cable of the water pressure switch and unbelievably I think it's open circuit. I'm getting 5v supply to sensor but nothing back on PCB from green signal cable. However, if I meter at sensor itself, green cable shows 2.5v.

Going to double check it now and replace cable if it is (I'm sat in loft next to boiler with laptop at moment)....freezing....

 

[The831Bunny]

Check that the connection plug to the pressure switch hasn't got wet from the old sensor leaking and corroding the small terminals of the plug. Shine a torch into the plug to check. You may need to get something small and sharp in on the edge connectors to clean them. Do this with the power off of course.

I have also had a couple of brand new pressure sensors duff out of the bag lately too

 

[mwildin1]

I found it was the pressure senser return cable open circuit. When I 'cleaned' the temp sensor the first time I must have moved the cable and that's why it worked (not me cleaning the sensor). I have just replaced the cable and the bioler started up first time. Don't know how it went open circuit though?

Maybe the original sensor wasn't faulty at all or maybe I damaged cable when exchanging, although it's easy to unplug and can't see how I could damage the cable. Ah well, at least we now have hot water and CH

Thanks for all your posts anyway.

 

[Agile]

Well done to have logically found a slightly unusual fault.

That would have kept perhaps 80% of boiler engineers scratching their heads for an hour or two.

Tony

 

[roederja]

I know this is a very old post, but I have a similar problem (connector corroded) and I was wondering how you replaced the cable? Did you replace the connector as well? It seems you have to buy a whole new cable tree just for the connector. Was hoping there was a better way - especially since the cable tree I need is out of stock everywhere.

 

[Deleted member 267285]

Yep, usually have to replace wiring harness if it doesn’t dry out. Surprised at the information given, since opening up that particular boiler, the cover forms part of the combustion circuit, and should be checked for correct operation afterwards.

 

[Agile]

The communication drilling is my terminology for the very narrow drilling in the block between the pressure sensor and the water part behind.

Only about 4mm diameter maybe and about 20mm long and I have found them blocked with dirt and not applying pressure to the sensor.