BIASI Boiler Problem

[Marcusf1981]

Hi,

Just joined up to post a query I have with my central heating. i'm going to get an specialist engineer in from BIASI but I would like to eliminate a silly fault or set up first.

Moved into a flat and with it is a BIASI Combi Boiler for gas. I cannot find the model number or a similar photo online. I've found a manual online for the RIVA COMPACT HE and it seems similar although maybe not exact.

The issue is central heating is not coming on automatically based on the time values for the boiler. I wake up in the morning and it's freezing however the boiler should be heating the flat for 45mins prior to me waking up. I changed the thermostat to a digital non programmed and this morning it read 14 degrees, set temp 21 degrees and it was calling for heat.

So I checked the boiler and the timer display said on based on the current time and settings. The applicance Operation Light is flashing quickly which means a fault has been detected. For some reason without touching anything on the boiler I started the hot water tap in the kitchen and the boiler fired up to heat our water. The tap ran warm and then the radiators started to receive heat.

Is there a common cause for the boiler failing on timer and correcting itself when the hot water runs?

I know it's not ideal I cannot find the boiler model but hopefully the description of the fault may ring some bells.

Thanks
Marcus

 

[Agile]

I expect you have a non condensing M90-24 !

Its probably a failure of the pump proving switch to be reliably operated. That can often be a bit of a problem to fix for anyone not familiar with that model,

Tony

 

[Marcusf1981]

Thank you, I have home care with British Gas so will get them in for a set fee of £99.

 

[Agile]

This can be fixed but depending on the exact cause in your case may not be something BG people seem very good at.

The boiler does NOT need to be replaced!

Tony

 

[Marcusf1981]

BG came round and it was the pressure in the system or should I say lack of it. Cold it was on 0.5 so he toppped it up to 1.75 and it worked fine.

I reckon it's not as simple as that though because the boiler worked all week but this morning appears to have been on for only half the time before we get the same failure. The pressure was at 1 and this is with the boiler working away to heat up the rads.

I'll check later the cold pressure and top up if needed.

What could be causing a pressure leak and is it dangerous?

 

[petefromleicester]

Sounds like the ch ntc thermister is out of calibration...have you put the boiler in test mode ?
is the led flashing ok when you go bed?
when you get up its fast ?
ch ntc ...

 

[Agile]

Sounds like the ch ntc thermister is out of calibration...have you put the boiler in test mode ?

Does that cause the system pressure to go down then?