# Silvia V1 brew pressure



## 30621 (May 7, 2021)

Hi Guys, this is my first post here, so hello to everyone. I've had my Silvia V1 since new in 2005 (Australian 240V version) and it has been without problems for all that time. The only time I've needed to get under the hood has been to install new steam valve seals/grommets and replace the plastic connector insulators with heat shrink. Basically it's been a tool and I haven't modded anything. Usage has been to make 2 x flat whites twice per day and the odd long black and espresso. 15 years ago I bought a PID kit for it, but never got around to installing it!

Anyway, to cut the waffle, I recently read that people are getting better brews by adjusting the brew pressure to 8Bar. Strewth, I didn't even know the pressure was adjustable! I was intrigued as to what the pressure on my machine was, so I went to the Ulka site and saw that they have published a pressure/flow-rate graph for the Ulka EX5. I did a flow test with my blind basket in the portafilter and from the graph determined that my machine is producing about 14Bar, way more than the recommended 8-9Bar. OK, no problem, I thought, I'll adjust the OVP. It was a big disappointment to discover that my OVP is not adjustable.

Are these machines set to run at around 14-15Bar, or has mine drifted out of spec over the years? Or, is this the "normal" pressure for these machines? Has the valve seat worn, and if so is it a matter of buying a new valve seat and away I go? Or, should I install the newer adjustable OVP? What to do? Any advice would be great! Thanks.


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## shadow745 (Apr 29, 2012)

Installing the adjustable OPV would be a great way to go, but the non-adjustable can be tweaked by adding/removing washers internally that affect brew pressure. Might not be as precise as the adjustable and of course a bit more effort, but still doable. Not sure about 14 bars being typical, but mine in stock form was fairly high.


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## 30621 (May 7, 2021)

OK thank you, I might try that before outlaying AUD80 on a new valve. I presume that decreasing spring pressure would lower the output pressure?


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## shadow745 (Apr 29, 2012)

Oztayls said:


> OK thank you, I might try that before outlaying AUD80 on a new valve. I presume that decreasing spring pressure would lower the output pressure?


 Yes, this will likely help...

https://www.coffeeforums.co.uk/topic/41385-silvia-opv-adjustment-oldampnew/?do=embed


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## 30621 (May 7, 2021)

Awesome, this is great. Thank you!!!


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## 30621 (May 7, 2021)

Well, as the fates would have it, the element on our Silvia gave way yesterday (Sunday). I think what happened is that the thermostat failed during the steaming cycle and the temp ran away. I had a massive amount of steam pressure when I started frothing and then "pop" she went. Oh well, 16 years for the element wasn't bad I guess. I've made a decision to upgrade the boiler, upgrade the OPV, replace the Ulka pump, replace the thermostats, install a silicone group seal and service the steam valve. In addition, I've dug the PID which I purchased in 2006, out of its hiding place. I never did get around to installing it all those years ago, so now will be a good opportunity! There were no instructions supplied with my kit, but I think I'll find enough info on the web to be able to get it going. So the old machine will get a new life for well under half the price of a V6. Basically it will be a V6 under the hood and with a PID.

So this morning I pulled the machine apart completely so that I could start on the rebuild and also determine all the bits that are needed. A couple of minor surface rust spots on the steel frame were fixed and painted with epoxy paint. I did run into a couple of minor problems due to corroded screws, but with the aid of some WD40, they freed up OK. One screw on the boiler was problematic and I ended up cutting a slot in it with a hacksaw, inserting the most robust flathead screwdriver I could find, and then with a vicegrip clamped the handle, I was able to wind it out. It never had a chance with that treatment lol.

In my searches, I had came across this aftermarket Silvia V1/V2 heater element. To install it in the V1 boiler, one must drill out the old heating element and then drill two holes 13mm in diameter. After I had finished placing my parts order and cleaning up the machine, I decided to have some fun to see if I could drill out the boiler. It wasn't too difficult at all actually as the boiler is a high copper content brass, so it is quite soft. After starting with 4mm holes where the old element connectors were, I was able to easily enlarge these to 13mm with a narrow step drill. So I might now be able to sell it with one of these aftermarket elements installed and that will help defray some of my upgrade costs 

Here is a pic of the element, stolen from The Expresso Shop UK. I hope they forgive me:


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## Norvin (Sep 10, 2014)

There is usually an overlimit thermostat on the side of the boiler to prevent damage by overheating. Perhaps yours is a really early one that doesn't have one?

If you just enlarge the holes, sometimes the replacement element will not seat due to richness in the casting near one of the holes. The richness is extra thickening to accommodate the thermostats. I have done two of those conversions, admittedly on the slightly later type with a flatter top, and had to mill some of the richness away to get a good seat.

Good luck with the conversion, I wouldn't bother with renewing the thermostats if I had a PID on the shelf.


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## newdent (Feb 20, 2021)

If you were drilling the boiler anyway, I'd have been tempted to install a temp sensor inside of the boiler as people have reported poor PID performance with a thermocouple stuck to the outside. Just a thought if you've not finished drilling yet and your PID would be compatible.


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## 30621 (May 7, 2021)

newdent said:


> If you were drilling the boiler anyway, I'd have been tempted to install a temp sensor inside of the boiler as people have reported poor PID performance with a thermocouple stuck to the outside. Just a thought if you've not finished drilling yet and your PID would be compatible.


 Hi, I haven't yet received the new boiler and all the other parts, so I don't really know how to implement yet. The thermocouple for the PID that I have was designed to fit into a well that is cast into the old V1 boilers, complete with threaded screw hole to attach the thermocouple. I'm not sure yet how I am going to install it into the new one. I was hoping that the new boiler version had something similar due to the fact that PID installations were becoming very popular by the time Silvia V3 arrived? From what you say, this is not the case. Mmm, I shall have to ponder this. As you say, a thermocouple inside the boiler would be the better and more accurate way to go in the absence of a well for that purpose in the new boiler. The only thing that worries me is introducing a new leak point.


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## 30621 (May 7, 2021)

Norvin said:


> There is usually an overlimit thermostat on the side of the boiler to prevent damage by overheating. Perhaps yours is a really early one that doesn't have one?
> 
> If you just enlarge the holes, sometimes the replacement element will not seat due to richness in the casting near one of the holes. The richness is extra thickening to accommodate the thermostats. I have done two of those conversions, admittedly on the slightly later type with a flatter top, and had to mill some of the richness away to get a good seat.
> 
> Good luck with the conversion, I wouldn't bother with renewing the thermostats if I had a PID on the shelf.


 Yes, the protection thermostat failed and didn't do its job. 😔

Yes, I drilled the hole away from the thickening in the casting, but it's still quite close so may compromise the seal. In reality the holes for the new element don't need to be in the original spots so I could have relocated them better I guess. I could still braze them up and drill new ones I guess.


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## 30621 (May 7, 2021)

The replacement boiler together with the adjustable OPV arrived. I took the opportunity to replace the original pump the pump as well. As most would know, it's not a difficult job. Probably the most fiddly part was playing with the various combinations of copper washers that would set the OPV in position.

Initially, the OPV was set at 5Bar, so I've reset it to 9 which turned out to be about 3/4 turn clockwise to achieve. Very easy! The new boiler is much faster than my old V1 and I'm getting much better steam.

Now for the PIV which I've had stored away for the past 15 years!


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## 30621 (May 7, 2021)

I now have the PID installed. I've been messing with the settings, but as yet have not been able to improve on the Auto tune settings. I still have to tidy the cords with some cord wrap, but the installation is done. The sensor is just a standard K-type thermocouple which I've installed onto a tinned copper ring and screwed onto the boiler using the steam thermostat screw. It's working OK but I've ordered an RTD Pt100 sensor with a 1m cable.

As I didn't have an enclosure for the controller, I looked around the house and found an empty hand sanitiser bottle to mount it in. It actually does a pretty good job so I'm thinking I might just paint in black and be done!

Time for a Yirgachefe!


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