Silvia - Low Flow rate suddenly?
I'm trying to diagnose an issue with my Silvia.
Basically I have noticed that it has been taking longer and longer to get the same volume in a shot without any changes to my setup/grind/beans/etc.
I get slow flow from the head as well as the wand.
I've done some troubleshooting:
- Backwashed and Descaled
- Full teardown, no blockages I can see in my 3 way valve, solenoid, pipes, diffuser etc..
- Backwashing works fine.
- I noticed that my OPV seal is breaking down, and looks a bit old.
- I tested my OPV by using a blind basket and get ~150mL over 30s at the loosest I can have it... it is a trickle at tighter settings.
- I get ~250mL over a minute from the head with no basket attached. (Much less than the 600mL or so it would be with what is basically no pressure?)
Do you think this is all related to the OPV? I would have thought that if the OPV was leaking/worn out my backflow rate would be much higher, rather than lower. If I loosen it off a ton, I get steam coming through the OPV when using the wand.
Could it be that the pump is not working properly? The pump has sounded a bit different recently.
Any advice would be appreciated!
Last edited by Jeffraw; 17th May 2018 at 09:02 PM.
You need to check your pump flow at no pressure. Compare that to the flow at the group with no portafilter. That will test to see if the pump is in spec, and will check for piping restrictions.
Also does your opv leak? You need to set it for its pressure and it needs to not leak at a lower pressure than this.
So I pulled the pump out and ran it with no resistance and it only gets about 250-300mL in a minute.... seems like it is well out of spec based on the pressure/volume curves im looking at.
Originally Posted by Jackster
OPV doesn't leak (Looks a bit brittle and worn so i'm replacing it anyway)
It does sound low. I have seen the flow/pressure charts but cant remember the 0 pressure flow...
You may be able to pull it down and clean the internals. Maybe the 1 way valve inside there is leaking allowing the water to not pump.