Rancilio S27 - Restoration? - Page 2

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

#11: Post by Coffcarl »

So if the machine is detecting a low water level in the boiler, the heater will not come on.

I would find the water level probe, which is the piece with the single wire attached to a spade connector, remove it by unscrewing from the top of the boiler, and descale it in a solution of diluted white vinegar. I think you will find after you do that, that the boiler will heat up. Maybe while you have it out you can siphon some of the water out of the boiler. You will not be able to drain ot with the method you describe unless you can get the heater to come on and pressure to build up.

I think most of the problems you will encounter will have to do with mineral scale, and once you verify correct operation, you will want to run some kind of descale solution through the machine. Avoid taking everything apart to do that unless necessary, because then you will have to order and replace gaskets etc.

jgrosjean (original poster)

#12: Post by jgrosjean (original poster) »

Some progress...

I siphoned empty the boiler, and then added back some water. Then tried to turn it on and got original behavior again... machine turns on, heating element goes on, but don't hear pump. This time around I also tried dispensing water from the hot water dispenser, and also tried dispensing water from the group head. In each case the buttons lite up, and I hear switches going, but no pump and no water comes out.

Next step is that I want to disconnect the heating element so that I can leave the machine on a bit longer when trying to figure why pump isn't working. I read here: Rancilio S27 Rebuild/Repair Started

> 2. If you are not sure about the heating element there is no reason
> you can't disconnect and tape off the power wires going to it for testing.
> Tape them off well, no need getting lit up playing with power and water.

And I think that's what I've done, I'm posting a pict here to verify before I turn it on. In particular does "tape off" just mean wrap the exposed metal on the wire endpoints with a few layers of electrical tape?


#13: Post by Coffcarl »

Did the boiler actually heat up? The pump won't come on to get water out of the hot water dispenser. The boiler pressure is what expels that. However, regardless of boiler pressure you should be able to pump water out of the grouphead. I would begin troubleshooting the pump motor, with the heating element disconnected.

jgrosjean (original poster)

#14: Post by jgrosjean (original poster) »

Coffcarl wrote:Did the boiler actually heat up? The pump won't come on to get water out of the hot water dispenser.
Ahh, no. And I knew that, just didn't quite know it well enough to remember. The boiler has felt slightly warm, but I never let it run long enough to fully heat up because I wasn't sure there was enough water since the pump hadn't been working.


But now that I've disconnected the heater I'm seeing more progress. I turned on the machine and for the first time heard the pump run. It proceeded to fill the boiler, and the front green indicator light illuminated. Yeah!

Unfortunately when I try to dispense water from the group head nothing comes out. The pump runs, but no water. I tried dispensing a small coffee and I tried dispensing two big cups. The pump ran 10 seconds for the small, 30 seconds for the two big cups. Are those times just based on timers, or are they based on data from the flowmeter? If from the flowmeter then I guess that's good, since they were different and automatically turned off after a time water must be flowing and being measured? But where it's going I don't know because nothing comes out group head.


#15: Post by Coffcarl »

It could be leaking from the heat exchange tube into the boiler. If you leave the pump running (to the grouphead) does it eventually overfill the boiler? If so, either the solenoid valve that switches between the boiler and the heat exchanger is not actuating, or you have a leak in the heat exchanger.


#16: Post by Coffcarl »

Revising my answer. I really think you need to check for blockages from scale.

Also, a poorly maintained machine may never have been backflushed, so there will be a ton of crud in the grouphead. You will have to remove it from the boiler, clean, and descale. Cafiza for cleaning, citric acid or vinegar for descaling.

Could be as simple as that, and maybe there is a top stop to the flow built into the controller so stops after a certain amount of time regardless of metered flow. Another bad possibility is a cracked heat exchanger. Need to remove the heat exhanger to inspect.

jgrosjean (original poster)

#17: Post by jgrosjean (original poster) »

I've taken off the group head. It doesn't look particularly clean, but I don't think I can see scale anywhere. I don't see any physical build ups that could block water. I can blow through all the holes in the head and easily make air come out the hole in the center of the circle in the head.

But I do think I see a problem in the 3 way solenoid that hangs down off the head:

In particular I think I see that water has entered the solenoid valve guide through one of the top holes, but I don't see that water has ever exited that hole, it's still completely dry. Does that seem like it would be a problem? If so how can I determine if the problem is in the value part or in the coil part?


jgrosjean (original poster)

#18: Post by jgrosjean (original poster) »

I'm not not sure if that last hypothesis was correct. Maybe the water got into the group head when I tipped machine. I just tried dispensing water without the group head attached. Expecting it would shoot out of the heat exchange hole in the boiler. The pump goes on when I do this, but no water comes out the heat exchange hole that would go into the group head, so maybe problem is before group head.

jgrosjean (original poster)

#19: Post by jgrosjean (original poster) »

Ok, last post of the night. Sorry for all the noise!

I think maybe there is something wrong with the heat exchanger. Since I have the heat element disconnected everything is normally cold when I'm trying to dispense water. This time I used a hot water source so I could trace where the water was getting too when I tried to dispense. And after setting all of that up, I also noticed that there's a light on the flow meter that flashes, I guess when water is passing.

Both indicators told me that water was going through the flow meter and into the top of the boiler to the heat exchanger, but no water ever squirted out the other side. Is there any easier next step other then trying to remove the boiler to inspect the exchanger?

Thanks again!


#20: Post by Coffcarl »

I don't think you will get away with not removing the boiler, or at least the boiler cap.

Remember i asked if running the pump to the heat exchanger eventually overflowed the boiler through the vacuum breaker? If so, then there is a leak in the heat exchanger. It looks like it butts up against a flange on the inside of the boiler and is secured by an internal thread. The siphon goes through the top into the center of the heat exchange tube, and the water flows out through an orifice cast into the boiler cap (i think).

I gather if a machine freezes with water in the boiler the heat exchange tube will crack.

Here is a thread that might help:

https://coffeesnobs.com.au/brewing-equi ... o-s26.html

I am sorry for being so cavalier about this machine in the first place. I guess I have had good luck with my machines and grinders.

You can use the 15% off promo code EP2019 that espressoparts.com sent me a while back if you can get it from them. Cafeparts.com has it for more, but it looks like it is in stock there.