Hi,
My Biasi boiler (24se model dated 1997) has developed a problem whereby it keeps switching on/off in 10 second cycles while in DHW mode. CH is fine. It only appears to be the flame/gas which is being switched off, the fan keeps running and the voltage stays on to the pump which leads me to believe the dhw pressure switch is working and the diverter is correctly switching over. Water comes out hot from the tap in line with when the boiler is actually on.
The temperature of the boiler never gets above about 65-70 but it will cut in and out on it's way up to this maximum. I can hear a relay chattering as it tries to make its mind up if is going on to stay on or go off.
I suspect the secondary dhw exchanger may be blocked but is this likely if the boiler cuts out before reaching temperature?
Further weirdness is that the boiler will occasionally switch on for a few seconds after you turn the tap off when there is CH demand present. It will then switch off for around 30 seconds before switching back on.
Temperature probes seem to be measuring OK.
Anybody any Ideas where else I could look?
My current plan is to take out both the pump and dhw exchanger for a quick inspection, or am I barking up the wrong tree?
My Biasi boiler (24se model dated 1997) has developed a problem whereby it keeps switching on/off in 10 second cycles while in DHW mode. CH is fine. It only appears to be the flame/gas which is being switched off, the fan keeps running and the voltage stays on to the pump which leads me to believe the dhw pressure switch is working and the diverter is correctly switching over. Water comes out hot from the tap in line with when the boiler is actually on.
The temperature of the boiler never gets above about 65-70 but it will cut in and out on it's way up to this maximum. I can hear a relay chattering as it tries to make its mind up if is going on to stay on or go off.
I suspect the secondary dhw exchanger may be blocked but is this likely if the boiler cuts out before reaching temperature?
Further weirdness is that the boiler will occasionally switch on for a few seconds after you turn the tap off when there is CH demand present. It will then switch off for around 30 seconds before switching back on.
Temperature probes seem to be measuring OK.
Anybody any Ideas where else I could look?
My current plan is to take out both the pump and dhw exchanger for a quick inspection, or am I barking up the wrong tree?