For some time I've had an issue with my Oscar generally if it's been on for a good while, say an hour or so, but occasionally not long after first turning it on. The safety valve will release and blow steam everywhere. I assumed this is an issue with the pressurestat (Mater) failing but in the reading I've done this morning, I'm wondering if it could actually be the microswitch. Anyone else been in my position? How do I tell which needs replacing, or do I just replace both and be done with it?
Announcement
Collapse
No announcement yet.
Oscar Pressurestat issue?
Collapse
X
-
-
Hi Hipsi
Do you have any pictures of your Pressurestat? Lets get a look at the model numbers on it. See if you can get a picture as well of your microswitch. These can be replaced independently of your Pressurestat with the precise model information for about 5 to 10 bucks.
That said, your safety valve releasing could be a sign of a few things. Your Pressurestat and Microswitch will control the energizing of the heating element. The microswitch is a SPDT (Single Pole Double Throw switch that in the machines low-pressure/cold state of your Steam Boiler, will allow current to pass through to the heating element. When the pressure increases, the membrane in the MATER pressurestat will change states and the physical deformation will trigger the SPDT switch to change from its Normally Closed state to its Normally Open position, cutting the power to the heating element.
If you are getting an over-pressure state in your Steam Boiler, it is possible your Pressurestat membrane is not activating and your SPDT switch is therefore remaining in the N.C. (Normally Closed) state and continuing to energize the heating element, or, your MATER Pressurestat member is change state and the SPDT switch is not moving between its two positions (from NC to NO poles) and cutting power.
There are other reasons why you might be getting an activated Safety Valve release. No need to attribute the fault source just yet to Pressurestat, but it is a possibility.
Do you have an Anti-Vaccum Valve installed? Are you getting a lot of steam from your group if you do a cooling/cleaning flush before inserting your portafilter?
I'd say don't jump to the conclusion your Pressurestat or Microswitch are the source of this fault just yet.
FYI: Depending on your model of MATER (110 or 113, or even something different) your Microswitch will act differently. Here's a picture of how these two models have different acting Microswitch connections and throws:
- Flag

Comment