# Vostok fault AL.01



## Tsangpa (Nov 26, 2017)

We've got a code AL.01 showing on a two group Vostok on the brew boiler. The heating element icon doesn't show that it's heating and the temperature stability during a shot drops from 93 to 85 Celsius.

Has anyone, especially @DavecUKand @Paolo_Cortese have a solution?

Thanks


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## DavecUK (Aug 6, 2013)

I've let Paolo know,

I think it's a temperature sensor fault...but I'm not 100% sure about Vostok fault codes. Definitely worth checking from the brew boiler sensor wires to whatever it's connected to, just in case it's only a loose connection. Also check the limit stat on the brew boiler but to be honest, if it's tripped, I can't see how it would generate an error code, normally the boiler simply wouldn't heat.

Paolo should be able to let you know the sensor specifications, so you can order one quickly within the UK, if needed. Again guessing but pretty sure the Vesuvius uses the same sensor.


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## Tsangpa (Nov 26, 2017)

Awesome - thanks so much Dave


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## Paolo_Cortese (Jul 11, 2014)

AL01 means that the problem is the temperature sensor broken, AL02 mean disconnected, could you tell me if the color of the wires on the sensor if are red or grey, thanks.


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## Jony (Sep 8, 2017)

This is why I use Acs. Sometimes it takes few days to reply. I know other companies are good I don't knock them, but maybe because I have ever use them.


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## Tsangpa (Nov 26, 2017)

Paolo_Cortese said:


> AL01 means that the problem is the temperature sensor broken, AL02 mean disconnected, could you tell me if the color of the wires on the sensor if are red or grey, thanks.


 Hey @Paolo_Cortese thanks for the quick response. I'll check that this morning. Where does the sensor enter the boiler? Just so I know I'm looking at the right wires 😁


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## Paolo_Cortese (Jul 11, 2014)

See the photo


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## Tsangpa (Nov 26, 2017)

Hey @Paolo_Cortesethe wires are grey to both boilers. I've hopefully attached a picture of the boiler I think is the brew one - the longer boiler.


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## Paolo_Cortese (Jul 11, 2014)

the display show which one is. in any case email us at [email protected] with your details so we can ship 2 new sensor.


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## Tsangpa (Nov 26, 2017)

Paolo_Cortese said:


> the display show which one is. in any case email us at [email protected] with your details so we can ship 2 new sensor.


 Hi @Paolo_CorteseI've just emailed you the address for the new sensor. Thanks again for all of your help and for @DavecUK help too. Once again you guys are showing how ACS and the forum are indispensable in terms of support


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## Tsangpa (Nov 26, 2017)

Hi @Paolo_Cortese than you so much for your help - I received the temperature sensor today - amazing I wasn't expecting it so quickly especially with the holidays. I've installed it and it now works ok but there's another issue. When I change it over the brew boiler was completely full with water, then when it was switched on and heating the pressure gauge in the machine on the water line feed rose from 4 bar to 16 bar. I've been pulling water through the groups - probably about 6-8 litres and when water is going through it drops to 4 bar. When I stop the water going through the group it goes back up to 16 bar plus.

I don't recall the other Vostok doing that so I think there's some other fault. Would you or @DavecUK have any ideas? Oh and by the way, Merry Christmas!!

Thanks again for all your help and support.


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## DavecUK (Aug 6, 2013)

Tsangpa said:


> Hi @Paolo_Cortese than you so much for your help - I received the temperature sensor today - amazing I wasn't expecting it so quickly especially with the holidays. I've installed it and it now works ok but there's another issue. When I change it over the brew boiler was completely full with water, then when it was switched on and heating the pressure gauge in the machine on the water line feed rose from 4 bar to 16 bar. I've been pulling water through the groups - probably about 6-8 litres and when water is going through it drops to 4 bar. When I stop the water going through the group it goes back up to 16 bar plus.
> 
> I don't recall the other Vostok doing that so I think there's some other fault. Would you or @DavecUK have any ideas? Oh and by the way, Merry Christmas!!
> 
> Thanks again for all your help and support.


 *My best guess*

The one way valve in the Vostok is probably letting by and I assume your inline pressure gauge may have a check valve as well. This creates a sealed system between the pressure gauge and the brew system. Cold water entering the boiler expands on heating which causes the pressure to rise to whatever your expansion valve is set to. If you open the expansion valve a bit (anti clockwise), you would see that pressure drop as water weeps out....but really it's meant to be set above 10 bar. Amazing how the valve in the back of the group hold up to it.

There might be scale or debris in the 1 way valve, or perhaps a defect in the internal O ring. If I am right any 1 way valve of good quality will do the job, as long as the thread size is OK.


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## Tsangpa (Nov 26, 2017)

DavecUK said:


> *My best guess*
> 
> The one way valve in the Vostok is probably letting by and I assume your inline pressure gauge may have a check valve as well. This creates a sealed system between the pressure gauge and the brew system. Cold water entering the boiler expands on heating which causes the pressure to rise to whatever your expansion valve is set to. If you open the expansion valve a bit (anti clockwise), you would see that pressure drop as water weeks out....but really it's meant to be set above 10 bar. Amazing how the valve in the back of the group hold up to it.
> 
> There might be scale or debris in the 1 way valve, or perhaps a defect in the internal O ring. If I am right any 1 way valve of good quality will do the job, as long as the thread size is OK.


 It's definitely something with the water inlet system I think. I'm used to hearing a switching sound when the boiler draws more water in and then closes off but I'm not hearing that at all at the moment. It's like there's a constant open flow of the water in, then when the boiler starts heating up the pressure shoots up as there's nowhere for the expansion to go. I'll try tweaking the suggestions - any pointers as to which bits are the expansion valve and the one way valve? Thanks again @DavecUKI don't know what I'd do without you and Paolo


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## DavecUK (Aug 6, 2013)

The click you hear is the fill solenoid, it's near the water inlet inside the machine. If it's not closing properly it might cause the problem. Check the wires are in place...when the V needs water, that solenoid opens, click, then closes quietly. A pressure sensor controls that solenoid...any drop in pressure below a certain level and it opens solenoid so mains pressure can fill..

Hold short dry wood or plastic rod against solenoid body will tell you if it's operating but won't tell you if it's sealing.


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## Paolo_Cortese (Jul 11, 2014)

The solenoid is used only to fill the steam boiler, the brew boiler is filled continuously from the mains without any valve. So probably a one way valve is locked and the water go back to the manometer. Remove the rear panel when you have a chance and I'll let you know what you should check but not before of the 2 of January because we are closed and I cannot make any photo or video. 
Merry Christmas to everybody

Paolo


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## Tsangpa (Nov 26, 2017)

That's great thanks @DavecUK and @Paolo_Cortese happy holidays 😁


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## Tsangpa (Nov 26, 2017)

Hi @Paolo_Cortese I hope you had a great Christmas and New Years holiday. I've taken the back off the machine and attached a couple of photos to this post. If you can let me know what needs changing to sort the high pressure issue out that would be great 😁


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## DavecUK (Aug 6, 2013)

That's the 1 way valve. The large hexagon shaped brass bit


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## Tsangpa (Nov 26, 2017)

Hi @DavecUK on closer inspection that valve is on the line feeding the steam boiler which on this machine is the fatter boiler at the back of the Vostok. As far as I can tell there are two feeds, one to each boiler and then some outlet pipes in parallel with the feeds that have valves on them to allow the boilers to be drained. The feed to the brew boiler comes from a connector that looks to be a pressure reducer that also has the pressure gauge attached to it. Hopefully the attached pictures should make it a bit clearer.


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## Paolo_Cortese (Jul 11, 2014)

Hi is there a one way valve under the brew boiler I'm not able to see from the photos.


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## Tsangpa (Nov 26, 2017)

Hi @Paolo_Cortesehere are a couple more photos of the pipe feeding the brew boiler. The copper feed goes into a silver coloured tee connector that goes into the bottom of the brew boiler. The other pipe from the tee seems to go to a copper pipe with an isolation valve on it that I presume is used for draining the boiler.


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## Paolo_Cortese (Jul 11, 2014)

ok the problem is that there isn't a one way valve that's why you read a residual back pressure.


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## DavecUK (Aug 6, 2013)

If your other machines pressure gauge on the inlet is different, perhaps no back flow check valve on it (unusual), or it's 1 way valve is leaky, then it may not show the high pressure. It would only show whatever the mains pressure is regulated too e.g. 2 bar.

1. I'm not sure from Paolos answer whether the machine should have a 1 way valve and it's missing?

2. If the Other Vostock doesn't have a 1 way valve for the brew boiler feed as well, especially if it's* not *doing the same thing?

2. Does it have the same pressure gauge?

4. Why this machine never did it before?


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## Tsangpa (Nov 26, 2017)

Yep I'm not sure about it either. I can't remember ever seeing what the pressure was on this machine before but I know from the other Vostok that when it's on and working the pressure shows as around 4 bar.

If it's ok to work without a one way valve on this one no problem, it's been working ok so far so that's cool. My main concern is that reading over 16bar or pressure seems a bit high for me. I don't know if that's normal for the brew boiler to get to that pressure - it's over 16 bar as that's as high as the gauge will go to.

My main concern is that I don't want to put the machine back into service if it's over pressure as things like that can go boom in all the wrong ways.


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## DavecUK (Aug 6, 2013)

Tsangpa said:


> Yep I'm not sure about it either. I can't remember ever seeing what the pressure was on this machine before but I know from the other Vostok that when it's on and working the pressure shows as around 4 bar.
> 
> If it's ok to work without a one way valve on this one no problem, it's been working ok so far so that's cool. My main concern is that reading over 16bar or pressure seems a bit high for me. I don't know if that's normal for the brew boiler to get to that pressure - it's over 16 bar as that's as high as the gauge will go to.
> 
> My main concern is that I don't want to put the machine back into service if it's over pressure as things like that can go boom in all the wrong ways.


 This will save you from going boom...I would recommend you lower the pressure by adjusting this valve...because of the way the Vostok works you could probably loosen this to a much lower pressure.


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## Tsangpa (Nov 26, 2017)

Hi @DavecUK unfortunately that valve is connected to the steam boiler. The only valve connected to the brew boiler is in this picture. Any ideas how I would adjust it or check that it's working properly?


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## Paolo_Cortese (Jul 11, 2014)

Don't move nothing, as I told you the problem is a missing one way valve to avoid to read a wrong pressure. On the pressure reducer there is a one way valve inside but the manometer is located between the brew boiler and the pressure reducer. To eliminate the problem it's necessari to assemble another one way valve in the bottom of the brew boiler.


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## Tsangpa (Nov 26, 2017)

Paolo_Cortese said:


> Don't move nothing, as I told you the problem is a missing one way valve to avoid to read a wrong pressure. On the pressure reducer there is a one way valve inside but the manometer is located between the brew boiler and the pressure reducer. To eliminate the problem it's necessari to assemble another one way valve in the bottom of the brew boiler.


 No problem. If you can tell me what part to fit and where to get it from that would be great - thanks again. Alternatively is it safe to use as it is without adding a one way valve?


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## Tsangpa (Nov 26, 2017)

Hi @Paolo_Cortese I'm just wondering if it's safe to start using the Vostok again without an additional one way valve between the brew boiler and the manometer? Is the brew boiler at a dangerously high pressure or is it just an anomaly with the manometer because there's no one-way valve between it and the brew boiler? Thanks again


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## Paolo_Cortese (Jul 11, 2014)

It's always safe the one way valve is used only to read on the gauge a right pressure nothing else


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## Tsangpa (Nov 26, 2017)

Paolo_Cortese said:


> It's always safe the one way valve is used only to read on the gauge a right pressure nothing else


 The Vostok is now back to making perfect coffee again. The manometer only goes over 16bar when the brew boiler is heating and then gradually descends back to 4 bar when the boiler reaches temperature. Thanks again to @Paolo_Cortese and @DavecUK for your patience and help. The support I've received with this and other machines is astounding. I'd never recommend anything other than ACS - thanks again guys.


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## Rincewind (Aug 25, 2020)

Excellent....always nice to see/read a happy ending....enjoy 😊


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