HX boiler water replacement

[fineline]

Hi!
I would like to replace the water in my HX boiler, what is the best procedure?
First, turn off the power, open the hot water handle and drain all the water.

A) Immediately turn the power back on and fill the boiler with water.
I heard that cold water touches the hot heating element, which can cause a shock.


B) Wait as it is for a few hours until the temperature of the heating element naturally drops.
The next time the boiler is turned on, fill the boiler with water.The power is turned off, but the hot heating element will be exposed for a while.

Maybe I care too much.

[JRising]

A) Immediately turn the power back on and fill the boiler with water.
I heard that cold water touches the hot heating element, which can cause a shock.


B) Wait as it is for a few hours until the temperature of the heating element naturally drops.
The next time the boiler is turned on, fill the boiler with water.The power is turned off, but the hot heating element will be exposed for a while.

A) Perfectly fine. The last thing the element will have touched as the water drained was liquid water at (near) atmospheric pressure. The element could not have been hotter than 100 degrees C if it was submerged in liquid water at atmospheric pressure as the boiler emptied and you know the machine was powered off.
When you turn the machine back on, the auto-fill process will begin refilling the boiler, if you're talking about your Giotto, it is smart enough to NOT power the element until the boiler-fill process is completed. The element will have had even more time to cool off. The cool 15 degree water won't be any problem for the warm 70 degree element.

B) So long as you're talking about your Giotto, it will never allow the element to heat for more than 6 seconds while the boiler fill probe isn't grounded. If you hear the boiler fill cycle begin, trust the machine to not be burning the element.

[homeburrero]

I would like to replace the water in my HX boiler, what is the best procedure?

Your HX boiler is a compartment inside the steam boiler, and there is no element inside the HX. Your only heating element is at the bottom of the steam boiler. The steam boiler, of course, is mostly steam at the top, but the HX, and the thermosyphon circuit normally stays completely full of water with little or no steam/vapor.

On your Giotto R, draining from the hot water tap only removes water from the steam boiler, not the HX. To safely replace water in the steam boiler, you can bring the machine up to pressure, turn the machine off, then open the water tap and let it drain fully from there. Let the machine cool a little before turning it back on and you'll have no problem with shocking the element. When you power it on, first the autofill and then the element power will turn on.


But to replace water in your HX you simply need to lift the lever with no portafilter in the machine. The pump will run water from the reservoir or waterline into the HX and out of the grouphead. This is what you do when your machine needs a cooling flush - - it injects cool water into the HX and through the group.

[fineline (original poster)]

I understand that the HX machine has only one boiler. Yes, it is a steam boiler. Sorry for the confusing expression.

Looking at the boiler cross section, the cold water supplied to the empty boiler touches the bottom of the hot boiler body before the heating elements.
So the temperature difference is even smaller.

[JRising]

On a Giotto, the boiler inlet is very near the bottom of the boiler. Approximately where the Blue Arrow is drawn on this picture.

[borrik]

I found some alternative way on cold machine using bike /auto air pump, but top cover of the machine should be opened to seal a vacuum breaker with selotype.
I'm sealing vacuum breaker, then opening hot tap and steam wand and pushing air into steam wand and all water exit via hot water tap (it usually connected to the lower part of the boiler so I believe most of the water leaving the boiler).

[JRising]

With a compressor on the steam wand, the air pressure will keep the vacuum-breaker closed while the water is displaced out through the water wand.