No CH on Biasi M110.32SM/E Garda Plus HE Boiler

[Tempus009]

Hi, I have a Biasi M110.32SM/E Condensing HE Boiler which produces loads of hot water but the CH starts up for a short time and then cycles and no heat is distributed around the system. I have had an engineer around and it worked OK when he came but since then the CH has died.
When it comes on the water circulates around the system OK but after about 10 minutes it sounds like the Diverter Valve operates and closes the CH system even although the clock is ON for CH and no hot water is being called. At this stage the boiler cycles and maintains water at 60C but nothing circulates around the radiators.
My engineer is waiting for a Main Circuit temp probe to see if that is the problem but I thought I would ask the experts on this forum if they have any ideas.
The manual says it could be the CH Circuit ( I think that is OK because when there is water circulating everything is OK), the PCB, the Main Circuit Temp probe or the Bypass Valve.
Can anyone shed light on this problem as I have a load of inlaws coming over the Festive period and my engineer won't be back for a while!
Thanks,
Tempus009

 

[Agile]

Oh dear!

This boiler has built in diagnostics but the one feature which might enable us to tell you whats wrong you have not told us!

What EXACTLY is each light doing?

Are both CH isolating valves in ine with the pipe or vertical if you prefer?

Is the room stat turned up?

What word is showing in the clock display?

What position is the second know in?

What do the lights do if you turn that knob to the "O" position?

Tony Glazier

 

[Tempus009]

Tony,
Thanks for responding.
The 1st and 3rd light flash together approx 2/3 seconds between flashes.
There is no room stat and so the boiler should be providing heat to the CH system.
Sorry, but I don't know what you mean with the CH isolating valves.
Clock display says "ON" but it is flashing.
Don't know what you mean by "What position is the second know in? "
With the boiler in the "O" position the 1st light flashes every 4/5 seconds.
Hope that makes sense.
Tempus009

 

[steve32]

Tony,
Don't know what you mean by "What position is the second know in? "

I think it should read knob

 

[Tempus009]

Probably right.
DHW is set at 6 and CH is set at about 4 depending upon outside temp. If it's really cold I turn it up to 5.
I have tried CH at all positions from 1 to 7 and if I set it at 7 the Temp gauge goes up to about 85C with the boiler cycling.

 

[Agile]

Sorry, I meant knob. I was in a hurry as I was on my way out.

The 1-3 lights flashing together means the boiler recognises a demand for heat.

The "on" on the clock should not flash but for the moment I dont think that it is relevant as the clock output is a single logic and the boiler seems to have accepted it.

I am wondering if the boiler is "keeping itself warm" ? Does the outside and particularly the top feel warm?

The CH isolating valves are where the left and right pipes underneath join the boiler. The square heads have a line through them which should both be vertical. Are they?

Tony

 

[Tempus009]

Merry Christmas anyone who is reading these posts!
Tony,
The boiler doesn't feel particularly hot at either the top or the bottom, just warm as you would expect with the boiler on.
When the CH is on and the CH temp is set at 4 the water temp gets up to 60C and stays there and the supply pipe gets hot for a while and then cools down. Sometimes the return pipe gets warm.
The CH radiators get warm on the top 6 inches but that's as warm as they get.
The CH isolating valve on the RH side is vertical and there isn't one the same on the left but a standard isolating valve which is ON to allow flow.

Before this problem the boiler and CH worked fine.
The boiler was installed about 4 years ago and this is the first problem I have had.

I hope the above helps.

All the best.
Tempus

 

[Agile]

OK, now its time to get some heating!

Remove front cover, two screws at the top, AFTER turning off the mains power.

Identify the black diverter valve motor at bottom left. This has three 6mm push on spade connectors.

Swap over the left and the right connectors! But DONT touch the centre one!

The repower the boiler and tell me what happens when you run heating and when you run hot water.

When you have replied could you text me so that I can come and look at it and reply to you. My number is in my profile, just click on "Agile".

Tony

 

[Tempus009]

Tony,
Off for lunch now and won't be back for the day.
Thanks for your assistance and I'll try this out as soon as I can.
Merry Christmas.

 

[Agile]

"Off to lunch" ?

Dont forget that you had inlaws coming!

I suppose some people intentially go out when the inlaws are coming!

Happy Christmas/

Tony

 

[Blooflame]

If diverter is faulty, could be goin round the DHW circuit?

 

[Tempus009]

Tony,
I had a look at the Diverter valve and the connections.
On my boiler the connector is a solid one iece with the spade terminals built into it. There is a solid piece of plastic on the connector to stop anyone fitting it incorrectly and so I don't really want to break the connector apart to try what you suggest.
I did take the actuator off and turned the CH on. The central pin comes down and returns into the body when you turn the CH off.
I suppose I could bodge the electrical connections with some wire and tape but not really what I want to try.
Any suggestions?
Thanks

 

[Agile]

If you can get the actuator to push down the pin then take off the connector.

It will then stay in the CH position until you either remove the clip and take it off ( recommended ) or you replace the power plug.

Try that and tell me what happens!

The earlier models had seperate spade connectors but yours is quite recent with the single connector. Sorry for the confusion.

Tony

 

[Tempus009]

Tony,
Got the pin down on the valve and we had heating this morning.
I had to go out and the time clock turned the heating off whilst I was out. The heating was turned on again (the connector was still not attached) but this time the heating did not circulate the system.
So I attached the connector to the actuator and the pin retracted.
I need to leave the whole system to cool down because I can only get the CH to start if the water temp is under 30C.
We are out until this evening and so I'll try again when I get back and see what happens this time.

 

[Agile]

Can you measure the resistance of the two sensors when the boiler is warm? Then again when the boiler is cold?

I dont think they are at fault but its easy to do.

When the boiler stops working does the timeclock continue to show "on" ?

Is the "on" ALWAYS flashing?

Are you competent to unplug the connector from the back of the timeclock? With the connector unpluged it should then work continuously on heating ( regardless of what the disconnected timeclock may show! )

Be aware that it is NOT polarised or keyed and MUST be fitted with the red wire upwards? Its easy to refit it wrongly?

Tony