Hi all,
I've searched the archives and couldn't find anything on this, so I think I've discovered something new. I hope not, and that someone has come across this before and knows the solution!
We have an Alpha CB24, which is connected to a load of thermostatically controlled radiators with TRVs on each one. One radiator doesn't have a TRV.
The boiler fires and lights ok, and I think I can hear the pump working ok. At first all the radiators seem to be working ok, ie they all heat up. Then, after about five minutes, the system cuts out and the Red A light comes on. The green B light is not on and is NOT flashing. After resetting the system, it works fine again for about 30 seconds, then the problem repeats. If we leave it for a little while, then it it takes a little longer before the system resets itself.
If the boiler is set to HW only, then it generally works fine, although it will occasionally reset itself (after a very long shower for example).
I phoned Alpha yesterday and they said that Red A light + Flashing Green B light = blockage in the system. I don't have the flashing green light (just continous Red) but it would tie in with my theory.
Basically what I think is going on is that the un-TRV'ed radiator is blocked. The system heats up properly, but then the TRVs all shut off. Once they've all shut off, then the boiler can't pump and shuts down. Leaving the system to cool for a while resets the TRVs and so the boiiler works again until the TRVs shut off.
Does this sound plausible?
I've just therefore drained and cleaned the un-TRV'ed radiator, but it was pretty good inside, and it does heat up ok. However the problem is still not fixed.
Anyone got any ideas?
Cheers,
Janos
PS - I checked the system a couple of months ago and it worked fine. No work has been done since.
I've searched the archives and couldn't find anything on this, so I think I've discovered something new. I hope not, and that someone has come across this before and knows the solution!
We have an Alpha CB24, which is connected to a load of thermostatically controlled radiators with TRVs on each one. One radiator doesn't have a TRV.
The boiler fires and lights ok, and I think I can hear the pump working ok. At first all the radiators seem to be working ok, ie they all heat up. Then, after about five minutes, the system cuts out and the Red A light comes on. The green B light is not on and is NOT flashing. After resetting the system, it works fine again for about 30 seconds, then the problem repeats. If we leave it for a little while, then it it takes a little longer before the system resets itself.
If the boiler is set to HW only, then it generally works fine, although it will occasionally reset itself (after a very long shower for example).
I phoned Alpha yesterday and they said that Red A light + Flashing Green B light = blockage in the system. I don't have the flashing green light (just continous Red) but it would tie in with my theory.
Basically what I think is going on is that the un-TRV'ed radiator is blocked. The system heats up properly, but then the TRVs all shut off. Once they've all shut off, then the boiler can't pump and shuts down. Leaving the system to cool for a while resets the TRVs and so the boiiler works again until the TRVs shut off.
Does this sound plausible?
I've just therefore drained and cleaned the un-TRV'ed radiator, but it was pretty good inside, and it does heat up ok. However the problem is still not fixed.
Anyone got any ideas?
Cheers,
Janos
PS - I checked the system a couple of months ago and it worked fine. No work has been done since.
