Ticking noise while brewing and steam escaping grouphead

Equipment doesn't work? Troubleshooting? If you're handy, members can help.

#1: Post by Marcello »


Recently I have more steam coming from the head of my Domobar HX Jr than I am used to. My pre-flush is about 15 seconds (boiler pressure is 1.0). However although the water is calmer, there is still steam escaping. Is this normal? I read somewhere that it might have something to do with the valves inside the group not closing well?

Another thing that is recent is a ticking sound while brewing. As soon as (or shortly after) pressure at the head goes up to 10 bar something on the inside starts making the noise. It's a steady sound and it influences the bar gauge since the needle jumps back slightly every time the machine ticks. Hope my explanation makes sense :roll: :?



#2: Post by JRising »

There should be no steam at all escaping your brew circuit while the machine is NOT brewing.
With the lever down, the brew valve should be closed, no steam should get past it. If steam is escaping, the water in the heat exchanger is boiling away. When you try to brew, you have to replace this water that has escaped while the machine was idling. The first few seconds of brewing will be steam blowing through your coffee grounds, then when the HX is done filling with brew water the brewing stages, pre-infusion chamber filling, and brewing begin.
The ticking noise may be the remaining bubbles of steam bursting through the gicleur (Passing easily and more quickly than the liquid, hence the momentary drop on gauge) while brewing.

Anyway. First things first, you'll want to replace the brew valve in that grouphead. (The valve above the group, accessible by removing the big hexnut on top)


#3: Post by Marcello »

Hi, sorry for my late reply. I think my description was not clear. There is no steam escaping the grouphead when idle. Only after the pre flush. After brewing the steam is mostly gone. Sorry not sure this is normal pre flush behaviour or not.

The ticking noise comes and goes. Last few days it was absent. However I also noticed a hishing sound (for the lack of other words :D ). This is not during warmup (red light is off). I made a little recording to make help explain. I will add a video of the steam produced too. Maybe this is just normal behaviour.


#4: Post by Gig103 »

Does your machine have a vacuum relief valve? That is the sound my machine makes when the relief valve isn't staying firmly closed.


#5: Post by Marcello »

@Gig103 yes it does. That's the bolt with the pin in it right? On top of the boiler. Could it be a matter of tightening it? Or should I push the pin? If the later... should the machine be warm or cold when I push the pin? Thnx again!

Edit... is cleaning an option or too much work for an 8 euro part? Replacing sounds easier and less time consuming.


#6: Post by Marcello »

Hi, would appreciate it if someone could chip in and help me out with what seems to be te vacuum relief valve. I did give it a few pushes and things seem te be quiet now. Might have removed an obstruction or something. However... if it comes back? Replace, clean??

Thnx a lot all!


#7: Post by nicholasnumbers » replying to Marcello »

I personally replace those valves instead of cleaning them. The seals do wear over time, and you're better off just replacing it instead of removing it and fiddling with a cleaning.



#8: Post by Marcello »

Thanks Nick! Like I said I haven't heard the hishing for a couple of days now. I will order a valve nonetheless since I expect it to come back at some point. As soon as it returns I'll replace it.


#9: Post by Marcello »

@nicholasnumber the hishing came back so I ordered a new valve and put it in today. Hopefully that solves it. We'll see in the next couple of days. I did for the first time look at how the valve operates during initial warmup. It's normal to have a little water sputter out isn't it? It makes sense but would like to make sure.

@JRising I ordered a new brew valve too, including a new spring. Changed those too and again hope I will notice a difference in the head temperature. Boiler temperature is still ok at 1. Since you ended with 'first things first'. Please let me know how to proceed, if I have to.

Thnx guys! Your help is appreciated. I am learning a lot here.


#10: Post by Marcello »

Hi again,

Seems like the new parts do their job. Unfortunately it's on to the next sound. The one I mentioned earlier: the ticking or clicking sound during brewing. Not sure yet but could it be related to the brew pressure gauge? It seems like the ticking affects the reading. I included a video in which the sound can be heard. I hope it's clear enough. Help appreciated!