Inexpensive and easy way to descale/flush HX boiler

Need help with equipment usage or want to share your latest discovery?

#1: Post by 'Q' »

I had this idea that should make it easy to fill the boiler of an HX machine with solution or rinse water without having to open or modify the machine.

Go to your local home & garden supply store and pick up one of these 1 or 2 gallon sprayers (use a brand new one and wash it out before using). Remove the spray wand and clamp the hose to the hot water pipe of the machine. With both water and steam valves closed, put your solution or water in the sprayer tank and pump it up. Open the hot water valve, then use the steam valve to control flow into the boiler. You could also use the sprayer empty connected to the steam wand the same way to blow out water in the boiler through the hot water tap.
Image ... %20sprayer

This should save a bit of trouble of having to get into the machine for some routine maintenance, and also save some wear on the pump.

I'm not going to go into the rest of the descale process since it's already been covered, but I think everyone will get the idea.

I haven't tried it yet, but I see no reason why it shouldn't work.


#2: Post by N2Coffee »

I've been thinking along the same lines while getting ready to descale my Andreja Hx, but these questions have come to mind. Using a garden sprayer with the boiler hot means working against 15+ pounds pressure and risking being sprayed with scalding hot water if the hose or connection broke :cry: . To avoid an accident, I'd consider using double-clamped automotive reinforced rubber hose and a check valve to connect to the steam wand. Wear heavy rubber gloves and goggles since you are working with a hot acidic solution under pressure. May be just as well to do the descaling as Teme and others have described and tilt the machine away from the autofill sensor to overfill the scale line. I'll let you know if I decide to try this instead of the usual procedure.
- Mike

'Q' (original poster)

#3: Post by 'Q' (original poster) »

Those sprayers are not high pressure systems at all, a few psi at most. I would not recommend trying to overfill a boiler that's already full and pressurized with one of these, it will most definitely fail. The idea is to fill it cold, then heat and drain it.

I was out-and-about today and stopped by the local home & garden store and picked up their cheapest one-gallon sized sprayer to try out for this idea. The initial results were good as I did a mock descale to test. The hose that comes with it is a little too small to fit over my water and steam pipes with the nozzles removed so an adapter of some sort is in order. I found a temporary solution of shoving the sprayer hose into the top half of the water nozzle worked for the purpose of testing, but a more permanent solution is needed.

After a little practice I found that if I pressurized the boiler using the sprayer to pump air in through either the steam or water pipe first, then doing the fill, worked best so that no water comes out the vacuum breaker. Otherwise, it was without issue.

The one-gallon size works well, but I think a two-gallon size would have an advantage with its increased capacity to hold the compressed air.


#4: Post by N2Coffee »

That's great. Filling the boiler cold is definitely safer. Did your procedure go something like this? Connect sprayer (empty), close water valve, open steam valve. Pump sprayer until vacuum breaker closes, then close steam valve. Pour citric acid solution into sprayer and re-pressurize. Open steam and water until solution comes out, then close both and heat boiler? The trick seems to be maintaining pressure while cold so the breaker does not open?

'Q' (original poster)

#5: Post by 'Q' (original poster) »

Did your procedure go something like this? ...
Pretty much, yes. Except I would pump/pressurize the sprayer before opening the valve it was connected to, then open the valve and pump a little more. This way the existing pressure would "pop" the vacuum breaker up quickly instead of my having to pump it quick to beat the escape of air through the breaker. I actually did it both ways and both worked, but this way was easier.
The trick seems to be maintaining pressure while cold so the breaker does not open?
Exactly. That was the only tricky part, but even that wasn't what I'd call hard. Once the vacuum breaker was closed, being careful to release the air slowly through the steam valve while pumping the sprayer had to be a little coordinated. This is where I think a two-gallon one would have an advantage over my one-gallon because there'd be more capacity for the compressed air behind the water/solution.

User avatar
Compass Coffee

#6: Post by Compass Coffee »

Interesting method. Only thing I don't get is how buying a tank sprayer is inexpensive versus not buying a tank sprayer for descaling duties. :wink:
Mike McGinness, Head Bean (Owner/Roast Master)

'Q' (original poster)

#7: Post by 'Q' (original poster) »

Well, $10-20 for a brand new "espresso machine accessory" is fairly inexpensive. Take a look at the price for a tamper or knock box or whatever. :)

As an alternative to opening the machine and disconnecting sensors, cutting wires to install switches, or what-have-you, especially for those machines that might still be under some kind of warranty and/or the owner is intimidated by the idea of f%!#ing around inside the machine and screwing it up... eh... who knows. Anyway, it's a (relatively) inexpensive alternative. Also it fills and empties a boiler quickly and, as pointed out above, works when the machine is COLD which adds a degree of safety too.

User avatar
Team HB

#8: Post by another_jim »

If you have a rotary pump, it works, since rotaries are flow through. Vibe pumps block the flow from the suction (inflow) side unless they are operating. For them, you'd have to disconnect the head (outflow) side pipe of the pump, and connect up there. You'd also need an easy connecting fitting to do so.

This does have value if you want to descale cold, or completely flush a boiler that has no drain. To completely flush the boiler, open the water tap, and after all the water has gone out using boiler pressure, you can get the last bit out using compressed air. This presupposes that the water tap is at the bottom of the boiler and not on its own HX; if it isn't you'll need to tilt the machine as well.

If it does work to completely drain a boiler, it is useful, because it can save the endless flushes required to get out the descale solution if the boiler doesn't drain well under boiler pressure.
Jim Schulman

'Q' (original poster)

#9: Post by 'Q' (original poster) »

Hey Jim,
Thanks for the response. You make a good point about easily being able to do a good complete flush of the boiler after descale. I believe it would be very effective and efficient at flushing with rinse water after the descale. I also like the point of being able to do the whole descale cold if one so desires. I was unaware that there are hot water taps on home machines that are on their own HX. That would change the process a bit.

Your point about vibe vs rotary pump is true. But for filling, by simply attaching the sprayer to the "hot water tap" and filling through that, you bypass the pump alltogether and thus it doesn't matter which style pump you have. In fact, my machine is the Expobar Pulser and has the vibe pump and I had no problem filling the boiler quickly and easily without disconnecting the hose on the pump. One of the main ideas behind this is to be able to do it without having to get "under the skin" of the machine, it can all be done externally.

User avatar
Team HB

#10: Post by another_jim » replying to 'Q' »

Ah. that makes more sense -- you can then flush through the steam wand. The only gotcha is that the vacuum breaker will be open when the machine is cold.
Jim Schulman