Boiler keeps on boiling water even heating is switched off

[luckyvictor]

The problem is, my ideal boiler logic heat h15 keeps on burning (igniting flame icon on) all the time, all day long, regardless of the programmed on off schedule for both heating and hot water.

when we have the heating turned off from the thermostat programmer (danfoss tp9000ma-si), i.e frosted protection at 5 degree, or it is "off" during the daily program. It still burning, heating water.

When we have both heating and water hot scheduled to be off, it still burning.

I can safely say that there is no demand called from the program and it just supplies. The temperature displayed on the boiler is always 70+, I expect it displays 00 sometimes to show no demand required.

I have had an engineer check when doing annual service, boiler itself is ok, but he doesn't know what this problem is, suggested is the motorized valve, but he can't prove it is not functioning, as he seems to prove that all 3 of them are working ( 2 heat zone, 1 hot water).

So any suggestions to my problem please? How may I track down the root cause and take action accordingly?

Right now the house is always burning hot, I have to manually adjust the radiator thermostat, as well as switch off the boiler itself to avoid unnecessary heat(money)

 

[Basher]

Ultimately your boiler "switched live" supply is turned on and off by microswitches in the motorised valves you have, irrespective of the setting of other controls. If one of the motorised valves is stuck, or a microswitch inside is welded closed, it would account for the symptoms you describe.
Any competent plumber or electrician ought to be able to get to the bottom of the problem, through electrical testing/ diagnosis.

 

[luckyvictor]

Ultimately your boiler "switched live" supply is turned on and off by microswitches in the motorised valves you have, irrespective of the setting of other controls. If one of the motorised valves is stuck, or a microswitch inside is welded closed, it would account for the symptoms you describe.
Any competent plumber or electrician ought to be able to get to the bottom of the problem, through electrical testing/ diagnosis.

So it has to be the motorized valves, can not be sensor or thermostat or programmer?

How may I isolate and identify the faulty motorised valve please?

Also, when I turned off the boiler itself, the heating system did gradually cool down, is it because the motorized valves 'working' and stop the hot water out? Or the valve still malfunction and draining all the the hot water out, since no fire is supplied to provide more hot water, so eventually all hot water drains out and system cools down?

My motorised valve is Honeywell 272848

 

[John.g]

You will have to remove the orange wire from each motorized valve at its nearest wiring centre when neither CW or HW programmed on and test for 230V between the orange wire and neutral (or earth), take care as one might be live with boiler switched off as the motorized valve (end switches) are supplied with a permanent live (grey wires).

 

[Basher]

So it has to be the motorized valves, can not be sensor or thermostat or programmer?

sorry to mislead you - the above items do need to be working, supplying power to the motorised valves for the boiler switched live to get power. So the room stat should be able to turn the boiler on and off, which you say it does.
Also you should have a thermostat on the hot water cylinder that supplies power, which should switch off when the water is hot enough. You don't mention that?
If that were faulty it might cause your symptoms

How may I isolate and identify the faulty motorised valve please?

I see John.g has answered this!

Also, when I turned off the boiler itself, the heating system did gradually cool down, is it because the motorized valves 'working' and stop the hot water out? Or the valve still malfunction and draining all the the hot water out, since no fire is supplied to provide more hot water, so eventually all hot water drains out and system cools down?

Valves don't drain the water out, they just stop/alter the flow. The water stays in the system and gradually cools down.

 

[fowlerboi]

Am I right in thinking that the orange on the valves gets its supply from the permanent live(grey) to the valve not the switch live which just actuates the valve (brown).

I think a stuck microswitch will fire the boiler without the programmer/ stat calling for demand.

I personally would give a different plumber a ring and get them to find out which valve it is and get them to change it. Mention on the phone it needs a bit of diagnosis as not all plumbers are electrically clued up and find one that is. I would bet good money on a stuck microswitch.

A faulty programmer could be a culprit if you’ve left your room thermostat at an unachievable level or the valves at the radiator in the same room as the thermostat has been meddled with. A good check will be if the room thermostat reads the same temperature as you think the room should be

 

[luckyvictor]

sorry to mislead you - the above items do need to be working, supplying power to the motorised valves for the boiler switched live to get power. So the room stat should be able to turn the boiler on and off, which you say it does.
Also you should have a thermostat on the hot water cylinder that supplies power, which should switch off when the water is hot enough. You don't mention that?
If that were faulty it might cause your symptoms

Yes, there is one, which is Codice 542794, I never touched it since day one so I just forgot to mention, it is set to 50 degree.
I am unable to find any manual of this thermostat, how to diagnose whether it is faulty pleaes?

Valves don't drain the water out, they just stop/alter the flow. The water stays in the system and gradually cools down.

My bad, i simply want to say that the valve didn't stop the water flow out and circulate in the heating system, and heat dissipated eventually.

 

[luckyvictor]

You will have to remove the orange wire from each motorized valve at its nearest wiring centre when neither CW or HW programmed on and test for 230V between the orange wire and neutral (or earth), take care as one might be live with boiler switched off as the motorized valve (end switches) are supplied with a permanent live (grey wires).

At the moment, I have turned off boiler, the programmer (hence hot water schedule as well as heat schedule), and I notice that 2 out of 3 of the honeywell motorised valves, the levers have 'resistance' and when i push it to manual (ON), it returns. 1 has no resistance and loose.

Does it automatically mean this one is faulty?

I cant remember what that service engineer did but he didn't manage to prove that any of the Motorized Valve is faulty.

 

[John.g]

More than likely, can you just remove the orange wire from this one.

 

[fowlerboi]

The valves typically have no resistance when open. Did you check with the power off?

If you did then I would suggest thats the culprit

 

[luckyvictor]

More than likely, can you just remove the orange wire from this one.

Just watched this video, so looks like my MV is always energised.

I am going to remove the orange wire later after lunch.

 

[luckyvictor]

The valves typically have no resistance when open. Did you check with the power off?

If you did then I would suggest thats the culprit

So I turned off from the circuit box, and two remain motorised when I move the lever, one remains loose

Here are photos of the system btw, the greens show MV are at auto position, with resistance, push to manual/ON and feel and hear motor springs it back to auto.

Red shows the suspicious one where lever is loose.

 

[Deleted member 120897]

Just watched this video, so looks like my MV is always energised.

I am going to remove the orange wire later after lunch.

All oranges are likely connected together, do you have a multimeter at all?

 

[luckyvictor]

All oranges are likely connected together, do you have a multimeter at all?

I do, what do you suggest please

 

[Deleted member 120897]

Tracing the wiring back to the valve, it might be easy enough to do by eye, if not remove all oranges, and test, with the power off, for continuity (buzzer) between the orange at wiring center and the orange at failed valve, then reconnect the 2 working orange wires.

 

[John.g]

The valve cable is relatively short, I would trace back from the suspect faulty valve to the wiring centre then just remove this orange wire and test for 230V, orange to N or orange to earth with power on but programmer off.

 

[luckyvictor]

I have removed the housing, but I am not too sure how to remove the orange wire from the MV end.

I tested continuity between orange and yellow/green(earth) from the wiring centre without remove any one of the wire, no beep.

I can see the spring operation when I move the lever of the good MV (circled green), and the suspected one, no spring action.

I really feel like swapping the motor between these two and see whether fault is carried.

 

[Deleted member 120897]

I have removed the housing, but I am not too sure how to remove the orange wire from the MV end.

I tested continuity between orange and yellow/green(earth) from the wiring centre without remove any one of the wire, no beep.

Who said to do any of the above? I said remove oranges at wiring center (wc) and test between orange at wiring center and orange at MV - no need to disconnect the orange wire at MV.

John said test between orange and earth at wc.

 

[fowlerboi]

You're not testing for continuity between orange and earth at the wiring center, you're looking for 230v.

Set the multi meter to the V~ symbol with the next highest number above 200. (if applicable for your multimeter)

You don't want to remove the orange from the valve just the wiring center.

I'm not sure that moving the head to a different body is worth doing as it won't solve your problem. You can take the head off the one that's "broken" and using a spanner try and rotate the shaft on the valve, if it rotates freely its just the motor that's knackered if its stiff then the whole valve needs changing

 

[luckyvictor]

Who said to do any of the above? I said remove oranges at wiring center (wc) and test between orange at wiring center and orange at MV - no need to disconnect the orange wire at MV.

John said test between orange and earth at wc.

So how may I probe at the orange wire at MV? I dont see any point that I can touch.

 

[luckyvictor]

Now I have removed the suspected orange wire, and turn back power on from fuse box, but there is no light on the wilo pump, and I turn on my ideal boiler and it just stays at zero...

What have I done wrong? So far I have only removed the orange from box and open the housing of the two valves...

 

[Deleted member 120897]

So how may I probe at the orange wire at MV? I dont see any point that I can touch.

Apologies, there doesn’t appear to be a point you can touch, was thinking of a Drayton valve. Looks like you’ll have to do a live voltage test or remove the grey wire for the corresponding valve at wc and test between these, if you have continuity then it’s closed circuit and faulty.

 

[John.g]

You don't probe it at the m.valve, follow the black cable back to the junction box or wiring center, on of the wires fom the cable will be orange, remove it

 

[luckyvictor]

You don't probe it at the m.valve, follow the black cable back to the junction box or wiring center, on of the wires fom the cable will be orange, remove it

Removed it now, turn back from fuse box, but no power is seen...

 

[John.g]

There is a blue wire in that box which is a neutral, probe with red meter lead on the orange wire and the black meter cable on the terminal screw where the blue wire is, meter set to 500/600v AC.