Biasi riva compact 24s

[scatmanjohn]

Don't come across many Biasi boilers so i am a bit stumped with this one.

It will be fine for ages and will fire up every time and then it decides not to play ball anymore.

Pump runs...fan runs...aps makes...sparking...gas valve open..ignition..and then in the instant that it ignites the red lockout light comes on.

I'm looking at a flame sensing fault (electrode/ignition sequence board) however when i simulate a flame sensing fault by disconnecting the electrode the speed at which it locks out is not the same.(ignition occurs and the sparking continues for about 3 secs before lockout).

Anyone familiar with these things?

cheers.

 

[undercover]

I come across similar problems with these Biasi's. Firstly, a 24s that would fire up and then lockout. Like you i though flame sensing fault but it turned out to be a loose connection on the C/H thermistor which completly through me.

Yesterday a 28s with the same problem - here we go again i thought!!. Eventual problem was the fan was not getting up to speed as the bearings were worn. Changing the fan sorted it straight away.

This landlords got 8 of the bu**ers installed so it looks like i'm going to be busy with them for quite a while

 

[bengasman]

sounds like board on the way out. worth checking if the earht is ok

 

[scatmanjohn]

The biasi tech help said try changing both thermistors but i am not too sure.

Once its up and running it will give hot water forever and will heat the rads up to full.

It will only lockout during the ignition sequence.

 

[undercover]

I think that the PCB checks both thermistors during the ignition sequence. Thats why the loose connection on the C/H thermistor was giving symptoms just like yours.

 

[scatmanjohn]

I will have a dabble with the thermistors when i go back.

I checked the resistance as per their tech help and both were in range.

Bloody thing

 

[bengasman]

Just remembered, at least I believe I am thinking about the right boiler. The connectors for the sensors can be a bit feeble and may be on but not connecting properly. Push them on, wiggle a bit and try to pull them off (gently). They should hold

 

[undercover]

Just remembered, at least I believe I am thinking about the right boiler. The connectors for the sensors can be a bit feeble and may be on but not connecting properly. Push them on, wiggle a bit and try to pull them off (gently). They should hold

Yep you're right - its what caught me out, although most things seem to be feeble on Biasi's

Only other thing i can think of is a faulty ignition board but that seems highly unlikely seeing as its igniting OK.

 

[bengasman]

Yep you're right - its what caught me out, although most things seem to be feeble on Biasi's

i disagree. the price of parts is quite solid

 

[bengasman]

done it again, but now on myself in stead of tony.
the quote is not right, i never disagree with me.

 

[Agile]

I think that the PCB checks both thermistors during the ignition sequence. Thats why the loose connection on the C/H thermistor was giving symptoms just like yours.

All the ignition PCB does is to receive a 230v supply and then it goes into the ignition sequence controlling the fan and the gas valve on/off solenoids.

Only the main PCB reads the thermistors and decides what power to send to the modulating coil.

I would be suspecting the wumf when the gas ignites might be turning off the APS at that point. Easy to test by seperately operating the APS. Probably different with cover off than on.

Tony

 

[scatmanjohn]

Twas the ignition board.

Maybe i am better on these than i thought

 

[Gasguru]

Open up the red/black ignition box (the CVI module)....it's common to find the connector pin and undersized resistor joints have broken.

 

[scatmanjohn]

Open up the red/black ignition box (the CVI module)....it's common to find the connector pin and undersized resistor joints have broken.

I think you are on a different beast here Gasguru.

No CVI unit on this one. Ignition pcb is under the cover next to the main pcb.

 

[ChrisR]

Would this sort of thread be better in the Gas Installers Only section ? I think so.
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