OK, you've got a lot going on here, and I'm going to suggest that you need to take a breath and try to separate some of the issues, one by one, to get this resolved. Some of what you're describing is normal, some maybe not.
For starters, there are two red lights--the one by itself on the right of the machine is the steam boiler; the one on the temp display is the brew boiler. Recognize that when both lights are on, only the steam boiler is firing. Brew boiler is firing when only its light is on. So in your comments, maybe clarify which boiler is firing. If you have a PID machine, then the brew light is blue instead, and maybe that's why you're only referring to the one boiler, i.e. there's only one red light. Second, I don't recall whether you have a vibe model or rotary. Given your "only a month old" comment, I guess you've got PID and I'll assume you have a vibe pump. I'll also assume you're referring to the steam boiler. Now then, the flickering lights syndrome is just indicative of something starting up, i.e. a boiler kicking on or a pump starting up. More likely the boiler, because it's a high draw item and will momentarily pull lots of current away from the circuit. The fact that your lights flicker tells me that the lights are on the same circuit as the outlet that you're using for the machine. You might look around in your house for a circuit that has less load on it, and/or is isolated. But, it's not the end of the world--the circuit breaker might trip if you overload, but that's about all that will happen. If you are able to run the machine and the lights together, the breaker is not tripping which means the circuit's rated load has not been exceeded. The reason your lights don't flicker once the boiler light is on is because the initial draw against the circuit (flicker) has been recovered, so that startup effect has passed. Regarding pressure fluctuation. For now, set aside grind differences and all that. Use a blind PF and set the OPV to 9 bar--12 is way too high for a couple of reasons. When you are setting the OPV lower, you will need to dial out the screw, then pressurize to see where you are. Then depressurize, dial out, repressurize, etc. If you go too low, you can pressurize and dial up to the correct pressure while the group is pressurized--you just can't accurately dial down while under pressure. Once this is done, does the pump hold steady at 9 bar against the blind PF? If yes, things are ok with the pump and OPV most likely. If not, then you've got other problems. With pressure against the blind PF, drain a bit of water from the hot water wand. In a moment, you hear a click and you will see the brew pressure drop some, because the pump has switched tasks to refill the steam boiler. It will then click again and pressure on the brew group will return to 9 bar. Also, the steam boiler light will come on, and your lights will probably flicker. All of what I just described is normal--in order for the machine to work on a 15 amp circuit, the machine's logic has to give preference to various operations, and can't do them all at once. This is a shortcoming of our machines--I make lattes every day, and as I pull a shot I'm steaming milk. About halfway through the shot, the steaming operation has drained enough water from the steam boiler that it wants to be refilled, and this takes priority over the brewing of espresso. So the pump clicks over to the steam boiler for a second or two, brew pressure drops, and then the pump clicks back to the brewing operation and brew pressure rises. Running the steam wand before pulling a shot will turn on the steam boiler, but shouldn't have any effect on the shot unless you get low enough in the steam boiler to refill it, and then that operation would happen before you're in the middle of a shot. Basically it shouldn't matter much if at all. For steaming, it is a good idea to purge/heat the wand until the red light comes on, and then start steaming while the boiler is still on--this gives you more powerful steam for a longer time. You might have a quick peek inside the top of the group, i.e. the giant nut on top, to see if there is any manufacturing debris that got missed in there. Just pull the parts out and have a quick look. But I'd do the other tests I mentioned first. Let us know how it turns out. b On Apr 10, 2011, at 8:27 AM, [email protected] wrote: > Apologies for starting a new threat on an existing issue, but things > just seem to be getting weirder re/ fluctuating brew pressure during > shots. As per my previous posting, I mentioned that Brewtus was making > my kitchen lights flicker slightly, and that this stopped when the > boiler kicked in. I also stated that when running, the pump would > oscillate slightly when the boiler light was off, but would stop > oscillating when the boiler light was on. So, here's where things get > weird - with looser grinds and lighter tamping, the pressure behaves > normally when pulling a shot. When I tighten the grind and tamp > harder, the pressure behaves erratically towards the end of the shot, > oscillating between 7 and 8 bar. This machine is only a month old, so > I'm pretty sure the OPV and pump are o.k. I'm wondering if this issue > is linked to the lights flickering issue - in other words, the > pressure fluctuates as the pump fluctuates slightly when the boiler is > off. Tighter grinds and harder tamping exacerbate the issue because > they increase pressure in the portafilter. I should also mention that > the oscillation seems to not happen if the boiler light is on. Looking > for potential solutions - backing off the brew pressure seems to have > helped some people with a similar issue to mine (currently set around > 12 bar at the factory). Also, was thinking of beginning my shot when > the red boiler light is on by running the steam wand before a > shot......ANY help/suggestions would be appreciated. > > Pete > > -- > You received this message because you are subscribed to the Google Groups > "Brewtus" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/brewtus?hl=en. > -- You received this message because you are subscribed to the Google Groups "Brewtus" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/brewtus?hl=en.
