Thefoodfundi Junior Member Joined: 29 Dec 2013 Posts: 1 Location: South Africa Expertise: Pro Barista
Posted Sun Dec 29, 2013, 3:53am Subject: Machine repair
I have a single group magister machine. It has recently started playing up. After making a few coffees the pump starts up as if the pressure has dropped, usually not a problem except it doesn't stop until the warning light comes on. I ah since switched it off and am now unable to switch it back on. The pump immediately starts up and runs until the light comes on. It is as if it isn't able to build pressure or unable to get water. The water is pumping though but pump won't stop and pressure not building?
calblacksmith Moderator Joined: 25 Nov 2007 Posts: 7,312 Location: Riverside, Ca, U.S.A. Expertise: I live coffee
Espresso: ECM Veneziano A1 Grinder: Many different commercial Vac Pot: 40s era Silex Drip: Milita, Bunn&Curtis... Roaster: Cast iron pan, gas burner
Posted Mon Dec 30, 2013, 1:08pm Subject: Re: Machine repair
We have a term issue going on here.
What warning light?
What low pressure causes the pump to run?
Is this a plumbed in machine or is it a pour over?
Where is the water running when you say it is running?
Is the machine leaking anyplace that you can see?
The way the machines work is that the pump adds water into the boiler, your machine is a HX with a rotary pump (from the example I found on the internet, you did not give a model number so this is a guess). It fills the boiler until the sensor says the boiler is full and turns off the pump and closes the valve to fill the boiler.
There is an electric (most of the time) that heats the water. It is the hot water in the closed boiler that causes the pressure to rise to about 1.3 bar, give or take a little depending on how your machine is setup. This temp is regulated by a device called a pessurestat, it measures the pressure in the boiler and turns the heater on and off to maintain pressure. When you brew, the pump turns on and the resistance in the puck causes a back pressure to about 9 bar of pressure. The pump only runs to brew with and to fill the boiler.
Your story does not fit the way the machine works, can you help us to understand?
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