Vizo 24 boiler - low pressure light illuminated

[judewilliams]

Hi all,

Hope someone is able to help. I have a vizo 24 boiler in my new house and can not get it to work. I have drained, flushed and filled the heating system - as i added a new radiator.
When i turn the power on to the boiler, I can hear the motor working on the 3 way valve - but after a few seconds the bar light starts flashing. The guage indicates a presuure of 1.5 bar though. I have tryed dropping the pressure to 1 bar, and increasing it to just shy of 2 bar - and always the same result on turning the boiler on. Following instruction manual - it advises that the fault must be the water presure sensor - one with 2 terminals connected. I have replaced this, and it has not cured the problem. This is making me think that I have missed something really basic in filling the system. Any help would be much appreciated. thanks

 

[Agile]

Didn't you read this forum previous posting before fitting the new LP switch?

Most likely you never cleared the blocked communication drilling!

Tony

 

[judewilliams]

Didn't you read this forum previous posting before fitting the new LP switch?

Most likely you never cleared the blocked communication drilling!

Tony

Hi Tony, thanks for the response - sounds like you know what the problem may be. I did not see any previous forum postings relating to this problem when i looked through. Is it possible to send the link to it so i can have a look. How would i go about clearing the blocked drilling, as when i replaced LP switch - i just drained, disconnected leads to switch and unscrewed and put new one in. Any more details would be very welcome

Thanks

 

[Agile]

There are so many postings about that problem.

Search for blocked low pressure switch.

Tony

 

[judewilliams]

There are so many postings about that problem.

Search for blocked low pressure switch.

Tony

Hi Tony, have seen all the info now - think the problem was that my search included vizo 24 and this problem did not crop up - however you are totally right, when you search as suggested - there are many discussions. I have read up on these, and drained and cleared out the channel - nothing of any substance found. I have checked the sensor for its mechanical operation, and can here a click on the contacts when pressure applied internally to it. I thought all was going to be good - but still no action. I tried another suggestion of removing the 2 wires and connecting them to trick boiler into firing, just to test, but exactly the same thing is happening. If i may, i will try and explain.

When first turning on boiler, the green light is lit permanantly and the 2nd red lightDHW sensor is permanantly lit. There is a very faint flickering, but not flashing on the Air pressure switch sensor, the low system pressure light comes on for about 2 seconds and then goes out.

When turning dial to both heating and hot water combined to create demand the following happens: The DHW sensor lamp remains on, the low pressure lights comes on permanantly for 2 seconds as you here the actuator working and then the low system pressure lights starts flashing. When the pressure light is on its off cycle of flashing, the very dim flickering of the air sensor light returns, but stops when the pressure light flicks to on.

Any suggestions based on this info would be valuable as I have just moved and really cant afford to get someone out just yet to look at it, and dont fancy boiling a kettle for a month or 2. Thanks

 

[Agile]

It sounds as if the PCB may have failled from what you say.

But I have not been there and tested the boiler so all I can say is "MAY" be the cause!

Thats the advanyage of getting an honest professional! If he makes a wrong diagnosis then you dont have to pay for parts that are not needed.

Sound are less honest and think its alright for you to pay for their wrong diagnosis. many of them get you to buy the new part or to pay for it up front.

Tony

 

[judewilliams]

Thanks for the tips Tony, just hoping that I manage to get one of the good guys. Based on your diagnosis, and i appreciate the "may be" - is there anything that I could do to reinforce the diagnosis. Have you seen this fault before? Sorry to rattle on, but really just trying to avoid unneccesary call outs and cost.

Again thanks

Jude

 

[Agile]

A fixed price repair from BG might be a better solution!

Tony