The table below is indicative only, but you may find it useful, the rule of thumb being an adjustment of 0.1bar for every 5 degrees Celcius of change in the ambient temperature

I now have experience of using the machine up to ambient temperatures in the low 20s (Celcius) coupled with the experience of a customer with a machine in Cairns, Australia, for the higher readings which is the basis for the table below

It may not sound like much, but you will taste every 0.1bar that you move the pressure stat by

If you are getting a lot of very dark brown areas in the crema the group is running a bit hot

Dark brown flecking is desirable, but solid areas of dark brown in the crema suggests the brew temperature is too high

We have placed the pressure stat right at the top of the machine so this is a very easy adjustment to make

HOWEVER: if you are not confident and competent in undertaking basic 'handyman' tasks like rewiring and electrical plug, for example, please do not attempt this task yourself; seek help from someone who is

Unplug the machine from the electrical supply

Remove the top cover

Remove the yellow dust cap from the pressure stat and put in a safe place as it needs to go back on when you are finished

Take a flat bladed screwdriver and turn 4 revolutions in the direction you want to move the pressure stat (anti-clockwise for a reduction in boiler pressure)

Reconnect machine to power supply

Keep hands and tools off and out of the machine entirely! (to ensure no risk of electrical shock)

Observe the pressure at which the stat now turns the element off at

Unplug the machine from the electricity

You now know the reduction in the pressure that 4 complete revolutions of the adjustment screw produces

For example, pressure stat switching off the element at 1.3 bar initially is now switching off at 1.2 bar, a reduction of 0.1 bar from 4 turns of the screw in an anti-clockwise direction (for example), or 0.1/4 to obtain reduction in pressure per turn

Then decide how much further you want to reduce the pressure, e.g. you want the element to switch off at about 1.15 bar, an additional reduction of 0.05 bar is required, needing an additional 2 turns of the screw in an anti-clockwise direction

Having made the additional turns, remove tools and hands well clear of the machine and plug the machine back into the electrical supply

Observe how close you are to the pressure you want the element to be turned off at

If further adjustment is required be sure to unplug the machine from the electrical supply each time

I know it is tedious if you are having to tweak the pressure stat many times before you get it to setting you want but it is critical for your safety that the machine is unplugged from the socket each time

Replace yellow dust cap over adjustment screw on the pressure-stat

Replace top panel, taking care to hook the folded edges in both of the front corners over the folded returns on the tops of the side panels

On tank machines the right angle folds in the top panel fit over the top edges of the metal box that holds the water tank - take your time to ensure this is correct

Refit the water tank (if applicable) after you have replaced the top panel and be sure to push it home firmly, but not forcefully, into the recess for the valve in the bottom of the metal box that holds the water tank.  If the water tank is not correctly located in the metal box the alarm will sound