# Draining ACS Minima



## Vollbart (Jan 27, 2019)

Hi,

I want to put my machine to sleep for a month or so. How should I drain the brew boiler?

Excuse the basic question, I couldn't find it in the minima guide. As a guess I need to turn the heating elements off as I did when I filled the machine, pull the hose out of the reservoir and turn the pump on?


----------



## MediumRoastSteam (Jul 7, 2015)

Vollbart said:


> Hi,
> I want to put my machine to sleep for a month or so. How should I drain the brew boiler?
> Excuse the basic question, I couldn't find it in the minima guide. As a guess I need to turn the heating elements off as I did when I filled the machine, pull the hose out of the reservoir and turn the pump on?


I can't remember, but doesn't the Minima have drain plugs? 
@DavecUK


----------



## MediumRoastSteam (Jul 7, 2015)

-


----------



## DavecUK (Aug 6, 2013)

Can't remember without opening mine up and having a look....If it does, it will be a blanking plug, with thread sealant, so probably not the best way. There is also not much room under there.

The thermal sensor in mine is fitted with PTFE and I have drained mine before (as a test) by removing the thermal sensor and using a big 150 ml syringe and tube to drain it...had to do 6 syringe fulls. You can remove any fitting from the top, but the sensor is the easiest and central. You do have to snip the cable tie holding the sensor wires to the main wiring bundle though and ideally disconnect it so the wires can swivel....although as a hack you can allow then to twist along their length (not a short length) and then keep the twist so when refitting it twists out.

*You can't simply remove the feed pipe and run the pump to drain any dual boiler machine, and most of them require a fitting to be removed to drain the brew boiler.* Two exceptions are the Verona (I asked for drain taps underneath) and the Crem One 2B, which actually has the ability to operate a tap under the machine to drain the brew boiler into it's very large drip tray...a great system.

I may well ask Paolo to put in a drain system if there is a blanking plug free....if there isn't, then it can be quite complicated to get done. it also depends on whether it's cost justifiable.


----------



## Rob1 (Apr 9, 2015)

Just for future reference:

Today I full drained the service boiler and refilled with distilled water. It was interesting to see a bit of sediment coming out despite my very best efforts, though there was quite a bit of sediment in there when I flushed the boiler a few times upon receiving the machine so it could just be some residual stuff. Anyway I removed anti vacuum valve as it was fitted with PTFE and it didn't require messing about twisting wires etc. So to expand on the above advice, it seemed the PTFE had been would clockwise and anti-clockwise across the threads. Most of it stuck to the top of the boiler kind of creating a gasket. It might have been possible to simply refit the valve but I decided to remove all the old tape and replace with new. It required about 5 turns with the tape folded across the threads (so 10 turns if you keep it flat). I tried with less a couple of times but it would leak. If that happens you don't have to wait for the machine to cool completely, simply open the steam valve until the temp drops below 100c and you can then remove the anti-vac valve (or whatever) without any pressure. I ran the fitting under water to cool it down so I could wrap more tape across the threads comfortably and tested until it didn't leak up to 125c. The hole for the anti vac valve is big enough to fit silicone tubing of a 10mm outer diameter. I siphoned most of the water off easily enough and you could use the syringe for any last remaining bits but I don't have one so just used lung power and my mouth which has a capacity of about 70ml...

Things you'll need on hand to drain the boilers:

Small adjustable wrench (or wrench of the appropriate size)

PTFE tape to replace any you might remove or damage.

Silicone tube or syringe with tube.

Funnel with a spout OD of no more than 9mm just to be safe.

I actually prefer draining a service boiler this way than heating up and draining via the hot water spout. For one thing you don't waste a load of energy heating up water just so you can get it out of the boiler, you don't have to run the pump off and on to fill it again, there's no stress to the heating elements as they sit there hot in an empty boiler, and finally you can fully drain the boiler with this method whereas the hot water tap will leave a few hundred ml in the boiler. E.G the TDS of the water using the hot water tap method dropped from 45 to 13 after being flushed once and fully refilled with about 1500ml water Vs 35 to 1 after being rinsed with less than 500ml water.


----------



## DavecUK (Aug 6, 2013)

Rob for the future should you want to drain via the water valve...the *heating elements in the service boiler only do not switch on until the level probe tip is submerged*, you cannot damage the heating elements doing that. Also (obviously) when the level tip is exposed and it autofills again the heating elements are off until the tip is under water again.

The other method is to simply* long press the right hand button of the PID* and *both boilers heating elements are disabled* (and stay that way even after power cycling). You can use this as well if you want.



It's essential when draining and refilling the brew boiler, as you want the pump to fill the brew boiler because there is no protection as in the steam boiler (this is a common issue on dual boiler machines).


Useful when pressure testing as you can switch on with a cold boiler and pressure test with no worries about the heating elements warming the water and thermal expansion affecting the results.


Handy when doing diagnostics (noise, bad heating element, board triac failure etc..)


To re-enable the boilers heating elements a simple press of the right PID button is all it takes.


----------



## Rob1 (Apr 9, 2015)

Thanks Dave, I was aware the heating elements wouldn't come on obviously by turning off at the PID and by not flicking the switch to the service boiler but I wasn't aware the element wouldn't come on until the level probe tip is submerged so that's good to know. I was concerned with the heating element sitting there at around 125c and then having 20c water thrown over it, I thought maybe it would cause a bit off stress but maybe they can easily withstand it.


----------



## DavecUK (Aug 6, 2013)

Nah they will be fine, it's incolloy 800, those temps are like a warm bath. once you empty the service boiler with the machine off, within 30 seconds the heating element has already dropped to way below 100.

Re the PID I wasn't sure people realised ALL elements were disabled regardless whether the machine is switched to brew or brew+service.

The fact that brew boilers in twin boiler machines don't detect low water level is a bit irritating, especially if you can't disable the heating elements and someone has helpfully drained the brew boiler before delivery. The very first thing I do with test dual boilers is disable the brew boiler heating element (if easy, even by pulling connectors) and then ensure I can get water from the group. I always start a new machine (to me) with the covers off so I can watch it start. It is another little hobby horse of mine to start seeing switches under the machine if necessary to allow the brew boiler to be disabled if it cannot be done in software. They only have to disable the low current (and often low voltage) side of the triac if its a 32V dc/230V AC one.


----------

