Chamber heater taking a long time to heat

Hi all,

I have a home made brewpi spark (based on Elco’s design). I am trying to ramp up from 18 to 21 degrees in beer constant mode and although it says “heating” it only turns on for a short time then back off on the SSR even through it has set the fridge temp to 32 degrees. In the space of 4 hours, it increased the fridge temp by 0.7 degrees.

I have made sure it’s not a fault with the hardware as if I set to a high fridge constant, it pulses quickly and increases the temp.

I am assuming that this is something to do with a brewpi setting but not sure which one. I will take days to bring up the beer temp by just a few degrees at this rate so I’d like to shorted that if possible.


You can’t really expect people to diagnose the problem without giving more information on your setup and settings.


RPI2 with a Spark Shield (Photon Core) running brewpi 0.4.3

I have an undercounter larder fridge with the FV in it. The fridge temp sensor is loose inside the fridge and the beer sensor is in a very thick bubble wrap pocket sealed on to the side of the FV. There are 2 SSR’s connected. 1 to the fridge and another to a 60w tube (greenhouse) heater in the bottom of the fridge.

As you can see from the screenshot, the temp is not increasing very quick when trying to ramp up at the end. It is not turning the SSR on even though it says heating. If I reboot the spark shield, the SSR for the heater turns on for around a minute.
As I said, I know it’s not hardware as when I set it to fridge constant and set a high number, the SSR turns on and pulses away until it reaches it.

Trouble is, I don’t understand what a lot of the settings are.


The beer temperature error determines the fridge setpoint (using the beer-to-fridge PID).

The fridge temperature error determines how active your heater is.
The heater1 PID determines the PWM value of the heater. If the duty cylce (percentage the heater is ON) is too low for the given fridge temperature error, you need to increase the heater1 Kp.

Thanks Elco. I actually hit reset on everything in the settings and it’s begun working properly. Don’t know what was wrong, I certainly haven’t knowingly changed anything in there.
As it’s near the end of the brew, I think I’ll rig up a water based test once this one’s done to see if all is ok or is anything needs tweaking.


Hi Elco. Your suggestions worked. I think the fridge is not working right now though. I used to be able to crash the beer to about 2 degrees using the beer constant. Although the fridge setting is -4, it now doesn’t get below 4.5. any ideas?