Thanks for such a detailed answer Brian! I think my first step is to replace the pressurestat since it's due (replaced the first one ~5 years ago) and will see if that solves the problem before breaking out the multimeter ;) Also, anyone have a source for the pressurestat pipe? Or barring that can someone confirm the size, length, and thread type on both ends so I can fabricate one from parts? I was able to reuse the old one last time with a CRAZY amount of effort to remove the plastic from the old copper threads, but was planing to order a new pipe this time after learning my lesson last time. However, those pipes seem to be back ordered everywhere.
Thanks! m On Monday, September 6, 2021 at 8:23:12 PM UTC-7 Brian wrote: > Hey Mike, > > > The reason the steam boiler is effecting the ability of the brew boiler to > heat is because power to the brew boiler is routed through the > pressurestat. The pressurestat has 3 prongs, one is the common where the > power is fed in. One is normally closed which feeds power to the steam > boiler, until the steam boiler comes up to pressure, and one is normally > open which feeds power to the brew boiler solid state relay but only when > the steam boiler is at pressure. This cleverly makes it so that the machine > can have two good sized heating elements without blowing out your > fuse/circuit breaker because both heating elements can never be on at the > same time. If you have a switch that disables the steam boiler what it is > actually doing is diverting power from the common prong to the normally > open prong. It's possible that the little bimetallic strip in the > pressurestat is not able to maintain contact with the normally closed > switch as the body of the switch gets hot in side the machine. When this > happens then it would be unable to heat the steam boiler, and since the > steam boiler never reaches the set pressure the brew boiler never heats > either. > > Both boilers also have a safety thermostat that are supposed to kill power > to the thermostat in the event of a pressure stat or temp controller > failure. It's possible the thermostat on the steam boiler is acting up. > These have been known to fail and are cheap and easy to replace. > > The other posssibility, is that since all of the power for both boilers is > coming through the relay box, that as the box gets hot it stops functioning > correctly. These boxes have also been known to fail. If you feel > comfortable working with a multimeter with the cover to the machine off, > the best way to check what is happening would be to let the machine heat up > until the problem occurs, and then unplug the machine and remove the cover. > Plug the machine back in and start tracing to see where you are no longer > getting voltage, test from the pressure stat common to neutral and check > that you get voltage on both sides of the safety thermostat, that should > help you narrow down where the issue is occuring. > > Best of luck, be sure to write back with any updates! > > On Sunday, September 5, 2021 at 4:12:39 PM UTC-4 Mike PDX wrote: > >> Hi, my Brewtus III-R has has been a workhorse for the last 12 >> years. There have been a few failures during that time period (PID, >> Pressure Stat, and Steam Pressure Gauge) but they really have been straight >> forward for me to fix. However a new problem started a few days ago that >> has me scratching my head since I’m not sure of the order of operations the >> machine goes thorough when switching between Steam Boiler and Brew Boiler >> heating. >> >> Here’s what’s happening… Machine turns on as normal each morning, tops >> off water reservoir (it’s plumbed) and then commences the heating cycle - >> first stem boiler to pressure at 1.3 bar, then brew boiler for a bit, then >> back to steam boiler when pressure drops to .9 bar, then back to brew >> boiler, etc… until the brew boiler reaches 204F and PID float commences. >> >> Everything seems normal right? But after 60 to 90 minutes of being at >> temp, the steam boiler pressure falls and the heating element does not kick >> in at .9 bar, but dropping below that threshold DOES lock out brew boiler >> PID float, even though the steam boiler isn’t active. Consequently both >> temps drop until there is no pressure in the steam boiler at all, and the >> brew temp hits ~150F (this temp seems to vary a bit from 130F at the low >> end to 165F on the high side) when the whole system comes back to life and >> the boilers start activating in sequence as they should. Sometimes the >> brew boiler will make it back to 204F and PID float, but sometimes it only >> gets into the 190s before the temp death spiral starts again. The only way >> to restore normal function is to shut down and allow the machine to cool >> for 20 to 30 minutes. >> >> My initial thinking was that the “low” pressure side of the pressure stat >> failed, hence blocking the call for heat to the steam boiler. But if >> that’s the case why does the brew boiler stay locked out if it's not >> sensing low pressure? Also, why does the system function for 60 to 90 >> minutes before the temp death spiral? My guess is that there is a sensor >> that fails when the internals of the machine hit a certain temp (e.g. why >> it only happens when the machine has been on for a time) and I also >> suspect that it IS the pressure stat BUT, would love to get the wisdom of >> the crowd involved here before ordering parts, since the brew boiler lock >> out is making me doubt that. >> >> Any ideas Brewtus people? >> >> Thanks! >> >> Mike >> > -- You received this message because you are subscribed to the Google Groups "Brewtus" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/brewtus/e7707d5c-39ef-4a3d-b85b-2c61a751fc39n%40googlegroups.com.
