Baxi solo 2 help please - not running (heating or hot water)

[spp1]

Hi,

I have a baxi solo 2pf 40 and I got back from xmas with the family yesterday, turned on the heating at the controls upstairs, and nothing. I then turned on the hot water and the boiler fired up as normal. Tried the heating again and no response from the boiler. Switched HW back on but no response. Since then I've not been able to get it to start up for CH or HW.

I can hear the pump running when I request heat or hot water. When I turn off the mains supply, the pump stops. This suggests the fused box on the wall is ok.

On the panel, there were no lights illuminated. This morning I replaced the fuse on the PCB and the "Boiler on" light was blinking on/off randomly. This light is now illuminated, but it still shows no signs of trying to fire up when I switch the heating and hot water on.

I'd hoped it would be the fuse on the PCB but I guess not. Can anyone offer any suggestions please as to what could be the cause? I'm supposed to be at work on Tuesday, it's cold and I need to sort this out! Hope someone can help!

Thanks in advance

 

[twgas]

Sounds, to me, it could be a combustion issue for which you need a rgi.

 

[spp1]

twgas thanks for the reply. May I ask why you suggest a combustion issue?

When I arrived back at home yesterday there was some hot water, so I assume it had worked earlier in the day. Then the strange behaviour of no panel lights being illuminated, then just the boiler on light illuminating since changing the PCB fuse, suggests it's electrical. But I'm not a plumber, just attempting to be logical!

I also notice you're in Kent. I don't know any reputable plumbers as I'm new to this area - would you be interested in helping? Do you work around the Orpington area?

 

[twgas]

The boiler on light means it is receiving a demand for heat. However, if the boiler sometimes works i may well be wrong.
Do you have a 3 port or 2*2 port valves, and a multimeter to do some testing?
Cant come and look, employed and dont do private work

 

[spp1]

The boiler on light means it is receiving a demand for heat. However, if the boiler sometimes works i may well be wrong.
Do you have a 3 port or 2*2 port valves, and a multimeter to do some testing?

Thanks for replying again. Since coming home yesterday it doesn't look to me like the boiler's going to work again if left alone.

Not sure what you mean re valves - I have a "Y" diverter valve upstairs...?

I do have a multimeter but only ever used it for my car.

My gut instinct is the pcb. When switching the boiler on at the dial on the boiler, a click can be heard, then 2 clicks when switching off - like a relay trying to turn something on/off.

Is my logic correct or am I way off the mark here?!!

 

[twgas]

It could be the pcb, they're not the most robust, but wouldn't buy one just yet. We might be able to sus this on here, can't guaratee anything though!
Turn both CH and HW off at programmer, then isolate the power to system, is ther now a spring pressure resistance on the manual lever on the diverter valve, or does the lever flop around ?

 

[spp1]

It could be the pcb, they're not the most robust, but wouldn't buy one just yet. We might be able to sus this on here, can't guaratee anything though!
Turn both CH and HW off at programmer, then isolate the power to system, is ther now a spring pressure resistance on the manual lever on the diverter valve, or does the lever flop around ?

I have my fingers and toes crossed I can get to the bottom of this! I did replace the PCB around 18 months ago by the way.

I did as you suggested above. I can push the lever and the resistance I can feel seems to be the motor. But this all appears to be normal. It appears to me the valve is operational. It always winds itself back downwards for hot water.

 

[Gas2Air]

If the boiler on light is on and pump running, the next step is to check, resistance to pilot solenoid, voltage to fan, that means opening the combustion box, which of course you can't do.

 

[picasso]

Turn the boiler thermostat off for 10 seconds and turn on again, this resets the boiler overheat stat just to rule it out .

 

[JBPHS]

If the boiler on light is on and pump running, the next step is to check, resistance to pilot solenoid, voltage to fan, that means opening the combustion box, which of course you can't do.

So why did you give advice on what to check if the OP (or any other person who could be reading this thread that are not Gas Safe Registered) cannot carry out work on the gas fitting?

 

[spp1]

I've done the on/off thing and this had no effect, as expected.

I thought the fan would be the next step, as this is probably the next stage in the ignition process.

But it does confuse me how I had no lights, then after replacing the pcb fuse, a flickering "boiler on" light and then a few minutes later a lit "boiler on" light. This is what makes me doubt the PCB. Is there anything I can check on the PCB or anything else a DIY-er can do to eliminate other possibilities?

 

[spp1]

any final comments or suggestions from anyone on what I can check myself? Otherwise I'll have to call out and find a decent emergency RGI.

Anybody in the SE London/Kent area?!

 

[geoff@cetltd]

any final comments or suggestions from anyone on what I can check myself? Otherwise I'll have to call out and find a decent emergency RGI.

Anybody in the SE London/Kent area?!

Right - you've turned off the temp control for 10 sec (did it click?), so it's not in lockout (there is a lockout neon). There are two mains supplies to the pcb -permanent and switched live (from the time clock or room stat) which needs to be there for the CH to come on. If the OH stat has not tripped out, the air pressure switch is in the correct position and the temp sensor (100kohm at 20 degrees) in conjunction with the temp control call for heat, the fan will come on. If it doesn't then nothing more will happen. (Forget measuring gas valve solenoids at this stage (which you CAN measure without getting inside the boiler, you take the measure it at the pcb end of the loom)

What is the resistance of the fan motor (measure it at the pcb end then you are measuring the loom as well)? it should be 50-60 ohms. My guess is that the fan has blown the pcb fuse, which is why the fuse has gone and you will find the windings are open circuit so now the fan doesn't operate the APS and the pcb will not go any further through its sequence

I'm surprised at gas2air and JBPHS, as RGIs for their incorrect responses