Refill boiler issues after descale

[Mas950]

Overfilled Issues after descaling.

I decided to do my yearly descaling a couple of days ago, I descaled with about 4 tablespoons of citric acid in about a litre of water and fed that through to the machine via the machines own brass pipe pulling the citric acid solution from a container.

I used about 4 litre of this citric acid solution altogether as I live in London and have really hard water, I thought I'd descale thoroughly before moving on to bottled water to protect the boilers.

I would draw about half litre of the solution through the steam boiler and less through the group boiler and let sit for a couple of hours until I repeat the procedure

After the descale, as I was flushing the machine from the citric acid solution, I used about 3 gallons of water drawing clean bottled water through the boilers via my flojet pump.

I noticed with the steam boiler that as I was drawing a large cup of water the machine wouldn't refill straight away, usually after drawing a cup of water through the steam boiler the refill kicks in straight away but yesterday I'd have to draw another full cup of water from the steam boiler until it starts to refill.

What was strange was once the steam boiler refilled, about a minute or so after it would do another mini refill for about 3 to 5 seconds, this would be repeated about 3 or 4 times and at the time I was thinking maybe the fill probe is coated with citric acid solution and needs to be flushed properly.

The steam coming from the steam wand was a very wet steam.l also and the the temperature was going a bit beyond the set temperature of the steam boiler.

I turned on the machine this morning and as the machine was warming up, I noticed from the other room a loud wooshing/ /water hammer sort of noise, as I came to check on the machine, it was heating up as normal and then I noticed that I all the water from my 5 gallon water bottle was all used up in yesterday's flushing, I refilled the water bottle that my flojet pump's wand is in and then noticed the same weird water hammer noise. I thought maybe the steam boiler is trying to refill whilst full and then after about a couple of minutes the machine turned off tripping the RCD mains with it.

Now whenever I switch the machine back on, the group boiler reaches temperature and as soon as the Steam boiler turns on the RCD is tripped and the machine turns off.

I took off the panels this morning and there is no leaking of water on the table top or within the machine apart from some small water dots /deposits inside one of the plastic sheating covering one of the heating element connections.

I'm assuming that the temperature or pressure of the steam boiler has set of the pressure relief valve which explains the loud noise and a tiny bit of steam/water got inside the plastic sheating and shorted out the boiler heating element?

If I replace the heating element, I wonder what was causing the steam boiler to play up like I mentioned above?

Any advice would be greatly appreciated.

[Mas950]

Just a quick update, on this evening I thought I'd put a hair dryer to the Steam boilers lid to dry it out just in case some electrical connection may be wet thus tripping the RCD, I plugged the machine in again and waited for the group boiler to reach it's set temperature and I was holding my breath that once the steam boiler turns on that it will not immediately trip the RCD mains, to my surprise this did not happen and the steam boiler started heating and the boiler light was blinking away, unfortunately after a couple of mins the RCD tripped.

The boiler didn't get very warm, it didn't get passed the hissing stage where the pressure in the gauge starts to rise.

With the machine unplugged, I touched the steam boiler lid and it was warm so the heating element is working however something is tripping the RCD?

[Mas950]

Another quick update,

This morning I fired the machine up again and once the brew boiler temperature was reached the boiler came on and didn't trip the RCD mains this time, last time the steam boiler was on for about 4 minutes with the water Luke warm and nowhere near boiling point when it tripped the RCD.

Today the boiler carried on boiling for about 8 minutes, I could hear the water boiling and the hissing sound which I think is the vacuum breaker valve breaker and then at this point the boiler decided to fill for about 3 seconds and suddenly just after the fill the temperature gauge went from it's starting position to just a bit past the green and into the red zone in a second and I heard a loud clunk noise straight after and then the machine turned off tripping the RCD mains.

I observed the temperature gauge which stayed at this position, I opened the steam wand and about a cup of low flow water deposited out of the steam wand with no steam at all and the gauge returned to it's starting position.

The loud clunk was a metallic kind of sound.

I'm assuming that the machine tried to fill whilst already full just as the temperature was going past boiling point and the loud clunk was the water maybe knocking against something or making something Knock.

I will try to clean/look at the fill probe as that is obviously filling the boiler whilst full, the boiler is full of low tds bottled water and that maybe the cause of the fill probe going haywire as up until now the machine has only had hard tap water fed into it.

Does the fill probe just pull all the way out without having to undo any nuts or bolt's?

[chas]

You may need to replace the heat element but first pull out the water level sensor and be sure it is clean. If so, or once cleaned, replace it, then empty the boiler by removing the brass bolt on the bottom of the boiler over the sink. Once empty and the bolt is replaced, try it again. This will tell you whether your problems are just an over filled boiler or whether the heat element has gotten moisture inside of it. This latter issue is the most likely cause, but it's cheaper and faster to test for an overfilled boiler first.

Should you need to buy a new heat element be sure to also order a replacement gasket for the lid as there is no way to salvage the current one.

BTW: If no water comes out once you have removed the bolt, you will need to shove a screwdriver through the hole in order to break through the mineral deposits (be sure you have let the machine cool down before removing the bolt or using a screwdriver so that you don't get scalding hot water all over your hand!)

[Mas950]

Hi Chas,

Thank you for your reply,
After the descale, as I was flushing the boilers of the citric acid, the steam boiler was doing 4 or 5 mini refills after its main refilling whenever I drew water out of the steam boiler.

Usually once it refills it stops refilling further unless I draw more water out.

If the heating element is faulty in any way then how is that blowing the pressure relief valve and what connection is there with the heating element and steam boiler doing 4 or 5 mini refills after its main refill?

I will try your suggestion with emptying the boiler of the low tds water and cleaning the level probe and hope that fixes the issue.

[Mas950]

Hi Chas,

I drained the steam of the bottled water, took out the water level probe which looked fine with not a mark on it, I put it in some citric acid solution for a few hours since I had it out anyway and put the machine back together, filled it up with tap water and the machine is completely fine, after it's initial fill up there was no more mini consecutive fill ups from the steam boiler.

The only thing I can think of was that the level probe was having difficulty with the low TDS bottled water and kept refiling which seems strange to me as the water although was soft water wasn't osmo water.

Going forward now, I'm afraid to use bottled water now, I will continue to use the hard tap water and descale yearly.

Thanks for your help Chas.