Single boiler machines can produce great coffee, but require a little more care than heat exchanger and dual boiler machines.
To prime a boiler, the machine hot water control is operated with the steam wand open until water appears from the steam tip. This procedure is essential on startup each day and should also be performed immediately after the steam switch is turned off after texturing milk.
With a single boiler machine, failure to prime the boiler can lead to an exposed heating element and its eventual failure. Repair can be up to $300 dependent on the machine, so these steps are not to be forgotten!
We recommend that each milk texture event be for no more than two milky coffees before the boiler is primed again.
This process requires time and some practise. As a result, we do not recommend single boiler machines for offices, busy families or other situations where distractions can regularly occur. Although single boiler machines are less expensive, they tend to be best suited to use by enthusiasts.
This short video by Espressotec explains the process very well.