Pump running constantly

[jim23]

Hi

Am after some advice as to where to start looking for a problem with a central heating system.

It is a S plan system with a Grundfos pump and standard 3 way motorised valve. The pump has suddenly started running constantly and the only way to turn it off is to switch off the mains supply to the boiler circuit. It runs constantly even when the control panel in the kitchen has HW and CH turned to off.

The motorised valve seems to be working ok in that it goes to all 3 positions, could it be a sticky switch in there somewhere? Would this cause the pump to run constantly even with no CH or HW 'programmed' on?

Or could it be faulty programmer?

Any help appreciatted.

 

[cross thread]

it is a Y plan with a diverter valve ,S plan is zone valves, could be the pumpover run depending on the boiler fitted

 

[Mark Br]

What boiler do you have?

 

[jim23]

I understand some pumps are designed to over-run but this one is still running 6 hours after the CH/HW is switched off-infact it just doesnt turn off however long you leave it.

Its not actually my boiler, a friends who's im trying to help trouble shoot. Havent seen it yet so not sure of make, likelly to be a boiler issue? Maybe some control/pcb on the boiler?

Regards

 

[Lower]

If its a baxi solo boiler its the PCB that needs replacing.

 

[jim23]

The boiler is an Albion 17669 . The setup consists of a Siemens programmer, Grundfos Alpha pump and Iifa(or something similar) 3 way valve. The valve 'lever' operates correctly when HW and CH are switched on. It doesnt look like there are any microswitches inside to get stuck.

Also on the side of the boiler is a L and G 'thermostat', presumably to turn the temperature of the water up and down. Obviously the pump is ok because its running.

Could the boiler be faulty? Would the type i have contain a PCB?

Regards

 

[wannocks]

I think that's the cylinder you're looking at. Albion don't make boilers.

 

[jim23]

Sorry, yes its the cyclinde thats the albion, the boiler itself is a baxi solo.

Where is the PCB situated in the boiler?

and i take it its a Corgi/Gas safe job to sort it out? Any idea how much one will cost and is this a common problem?

Regards

 

[Lower]

this fault on a baxi solo is very common.

if i remember correctly i paid around £50 for a new pcb. I'm not sure whether fitting technically needs to be done by a gas safe engineer but it doesn't in reality. It's only a couple of connectors to disconnect and swap over.

 

[bigpkr]

this fault on a baxi solo is very common.

if i remember correctly i paid around £50 for a new pcb. I'm not sure whether fitting technically needs to be done by a gas safe engineer but it doesn't in reality. It's only a couple of connectors to disconnect and swap over.

Some PCB's require the burner pressure setting up which would require a gas safe engineer.