Biasi Garda Hot Water Problem?

[Earlybird]

My Biasi Garda HE doesn't give hot water when the clock has programmed CH off. CH is off for much of the day - so no hot water if it's needed. I thought the clock was only supposed to control the CH and that HW was supposed to be available at all times?

Also when CH is on and HW run, it starts off hot, goes to tepid but if left running goes back to hot again. Difficult to run a large sinkful, let alone a bath (which we don't have fortunately).

Is there a a problem or is this just a naff boiler? If there is, is it something I can do myself or will I need a plumber with the right test gear?

PS - can't just throw the front switch because the unit is in the loft out of the way. We only have a small house you see.

PPS - I never have liked combis but I thought that after all these years they'd at least have got them to work sensibly

 

[gas4you]

Check out the diverter valve.

You should get instant HW 24hrs a day as you thought.

 

[Agile]

Identify the diverter valve motor and remove the clip ( thats all! )

That should give you DHW whenever you run the hot tap. You should also see the red led light come on towards the back right when DHW is taken.

If the DHW is fine with the diverter valve head clip off then remove the motor and look to see if the bottom part is wet.

Tony

 

[Earlybird]

Blimey you lads are good

I've found the valve in the diagram - got to take the ruddy dog out first before it starts raining again and then I'll check what you suggest. Is it easy to find this clip?

I'll let you know how I get on - be nice to be able to tell my son what to do with his rude comments about our domestic plumbing arrangements

 

[Earlybird]

Ooer - I hope I've done the right thing.

The only clip I could find secures what I guess is the valve actuating motor to the top of the valve. I yanked it forward out of its slots and the motor popped off the valve.

Now I assume if I've done it correctly, because I've done it while the CH is on, the valve is open so even when the clock switches off and the motor operates it won't activate the valve, which will stay open giving me constant HW.

How'm I doing so far?

And the motor is nice and dry I'm glad to say.

Let me know if I've messed up - I can soon replace what I've taken off. But I have to say, I've just tried to run a sink of hot water - managed half before it just began running tepid and stayed that way, so I'm not too optimistic

PS - just had a thought. Maybe I removed the motor when the heating was not actually running so the valve wasn't open? Or maybe it's got to be done when the system is switched to hot water only (and water is being drawn)?

 

[Earlybird]

I think there's either a fault or this is just a naff model.

I switched over to no CH and HW only. The burner and pump activated for a few seconds. Then tried to run a sink of hot water. Same as before. Half a sink and then tepid. You could never fill a bath with it.

Can't be right can it? I'd do better to boil kettles

 

[gas4you]

When running the hot water, does the ch flow pipe under the boiler (far left as you look at it) get warm/hot?

If so the DV is stuck mid position.

 

[Earlybird]

Thanks Dave (and Tony). Difficult to tell as the heating's running and CH F and R are both hot anyway. I'll wait until the system shuts down and cools later and give it a try. I've replaced the black object on the top of the valve for now.

Seems to me as though it's not responding to a demand for hot water but just supplies what's there while the heat exchanger's hot. Once that's gone you've had it. Does that make sense?

Should be easy enough to check once the CH has timed off. Hot tap on should make burner light I guess and being a bit stupid I haven't checked that before

 

[Agile]

With the motor clip off run the DHW.

See what the green lights are doing and tell me. Keep checking them on DHW when the water goes tepid.

See what temp the temp gague goes up to and tell me.

Start again and watch the gas flame size and see what that does at the moment it goes tepid, or rather a few seconds before.

Tony

 

[Earlybird]

I think Dave's probably hit it.

CH off on clock. Temp gauge 31
Run HW, burner lights and green lights flash alternately

But.. feel CH flow and I'm pretty certain it's getting warm.

I left it to cool and was just going to try again when the heating came back on again on the clock

I'll try again this afternoon when it's all had a chance to cool down again.

PS - b*gg*r forgot to take the actuator off the top of the valve again but probably didn't affect the conclusion because the heating was supposed to be off anyway when I tried it

 

[Agile]

You must do this test with the motor head unclipped and feel the CH flow pipe some way down the flow pipe or better feel the flow pipe into some of the rads as well.

I dont think its the diverter valve as that would give continuously poor DHW performance after the first litre of hot water whereas you say that it cycles from hot to tepid and back to hot.

I need you to do this test for a while whilst you monitor the conditions where it does the hot/tepid changes.

It would also help if you could time the hot-tepid-hot changes over a good while like 10-15 minutes.

This is a very good and reliable boiler but obviously there is some problem with yours which I can identify if you can do the tests for em.

Tony

 

[Earlybird]

Tony, I couldn't do exactly what you asked but this is what I did find.

Actuator unclipped
CH programmed to off
Temp gauge about 33ish (when I looked after running HW for a little while but forgot to see what the initial reading was, sorry)

Start to run DWH
Burner lights
Green lights flash intermittently
Can see red light over the back is on
Water never above tepid (it's hot to start with when CH is on and then goes to tepid)
No heat going into CH flow - checked away from the boiler along the pipe at several distances and when I checked the DV it was still cold.

I think I was wrong anyway about water starting hot, going tepid and becoming hot again, at any time. I've tried several times since to duplicate and it has never got hot again if you keep it running once it has cooled.

I'm mystified - how come the burner can be alight and water not get hot - it wasn't being run that fast (certainly nowhere near fast enough for a shower or bath).

Right - with the actuator removed, CH has programmed on, burner lit, grren lights flashed, pump started and temp gauge rose to 60ish. Then it all stopped apart from the pump.

No hot water is entering the CH flow - DV is hot, so DV must be closed.

Have I removed the actuator at the wrong time? Do I need to refit it and start again?

With it in this state I then ran hot water again. Burner lit, green lights flashed. This time it started hot but went to tepid and gauge fell again to around 33ish. But still no hot water entered the CH flow.

Have I removed the right thing? The black actuator on the top - what about the smaller actuator thingy on the front of the valve which is also secured by a smaller clip?

I'm now refitting the top black actuator as otherwise we'll have no CH from the look of it.

OK I'm back. Did that. As soon as I switched electric back on everything started up and CH flow started to get hot. No complaints about CH at all.

Temp began to show a fall. Started to run hot water. Started hot but not as hot as before and went tepid even before I could have a pee (all that running water ) and didn't get any hotter over several minutes.

Could it be secondary heat exchanger (he said, sounding as though he knows what he's talking about, which he doesn't)

 

[Agile]

You have done the right thing.

Unfortunately viewing the lights was an important aspect of the test..

Its no good just saying they are flashing!

They flash differently on CH and on DHW and its important that you tell us exactly what each light is doing including in relation with the other lights.

Can you measure the resistance of the temperature sensors with the boiler completely cold?

If that runs normally then the next test will be the inlet and burner gas pressures but you will need a competent CORGI for that.

Tony

 

[Earlybird]

Hi Tony, have got a Robin meter so if that will do it, just need to know how.

I see in the Service Manual that the actuator needs to be fitted to get CH as the spindle has to be pushing downwards to work the DV.

I'm not optimistic at this stage as there seem to be so many things that it could be

 

[Agile]

Unfortunately viewing the lights was an important aspect of the test..

Its no good just saying they are flashing!

They flash differently on CH and on DHW and its important that you tell us exactly what each light is doing including in relation with the other lights.

If you can tell me what I ask then I can tell you whats wrong with your boiler.

I would prefer you not to read the boiler book as that only confuses you.

Tony