Elizabeth V3 overheating steam boiler, poor temp reading

NewyChris

Hi, and thanks all for contributing to (or running!) an amazing forum.

It’s time for me to iron out the kinks! I’ve run this machine for a few months since getting second hand. It makes great coffee, does not appear to have internal leaks, but the steam boiler does not always read correct temperature and overheats (safety valve vents as it should around 160deg, making a racket). Turns out the racket is the steam cavitating in the tank - lift out the hose and it makes no noise (but burns your hand, if you aren’t careful).

When I fire up in Eco mode, no noise. Great coffee.

It has been serviced once (by Jetblack), and again to deal with issues not rectified.

The original issue was steam safety valve was going off. I didn’t know it at the time, so the first fix was the anti-vac (blame Jetblack). In chasing down the problem, they also replaced steam wand hardware (main tap and all o-rings) and safety valve. Eventually discovered inconsistent temperature reading, and replaced steam boiler temp sensor.

Issue persists. Hard to pin down what is going on, as I have to hold down the + button to see the steam temp. Wish I could lock it on, to watch what’s happening as I steam. As an extra issue, occasionally the steam runs out of … puff … really quickly. I suspect in relation to thermostats or something. I read a similar issue on here somewhere. See pic of steam temp getting way up there (set to 139).

I often vent steam or a bit of hot water to settle the system. Once it gets over it, if I leave it on it seems to play nice. Seems to be a heating-up thing?

I made the best video I could with two hands. Doesn’t show the overheat, though.

Video - sketchy temp

Given how much has been replaced, I’m a bit at a loss. I wanted to check in here before I go back to Jetblack, as I have gathered the knowledge here is far beyond retail services.

DavecUK

NewyChris I’d say the steam boiler temp sensor is still faulty!

Clodius

I would agree with Dave. Easy enough to replace

NewyChris

A brand new temp sensor though – are they that unreliable? I’m happy to hit up the shop for a new one, but I wouldn’t blame them for taking a sceptical view. I’ll show them the video I guess

Though, I can’t think of anything else it could be unless it was a wiring issue (pls no).

DavecUK

NewyChris A brand new temp sensor though

I’m just telling u those are exactly the readings of a bad sensor.

NewyChris

Thanks Dave. Back to the shop!

As an aside, it’s impressive to read through other discussions and the knowledge you have about machines, esp this one.

DavecUK

NewyChris As an aside, it’s impressive to read through other discussions and the knowledge you have about machines, esp this one.

I helped redesign this one…which is why.

NewyChris

I would like to revive this question. I took the machine back to JB and had the temp sensor for the steam boiler replaced. They did it under parts warranty, which is great. Now on my third steam temp sensor. About a month of happy operating, and the same issue has resurfaced.
It seems strange to me, as a stuffed sensor should just be stuffed. If it starts to purge via safety valve, I know it’s having issues and I can usually set it straight by running 100mL or so through the hot water tap. The steam temp sensor jumps up to real temp (usually about 160, occasionally having a real wobble first), and then has no issues while the machine remains on.
I wonder if there isn’t anything else that could be contributing to the issue. I don’t know the mechanics of the internals (or even how the temp sensor actually functions), but unless JB had a whole batch of dodgy steam temp sensors (possible), the stats are adding up to support an alternative.

Clodius

What about descaling? Maybe the heating element is too scaled up and it’s being overworked.

NewyChris

Clodius

I assume the heating element is triggered by the temp sensor. So, it is being overworked from that perspective, but I’m not sure how it could drive the current issue. Something to think about. We have really good water where I live, so scaling isn’t a huge concern

Clodius

I can only tell you what I did. Not an expert by any means. I undid the water level probe, the central joint (for the hot water) and the anti vacuum valve just because they were leaking. And since I had them off I shined a light inside which scared me, there was so much scale inside. It took me a bit of time cold descaling it but it’s now squeaky clean, including the water level probe that had scales as well

NewyChris

That’s wild, check out all that mess! What’s your local water like? The service places around here reckon they don’t generally descale machines, but they might just be averse to the effort.

Were you having a similar issue with overheating?

The descaling is an intimidating process, but maybe I’ll put it on the cards. While nothing is leaking, I’d prefer not to take it apart myself. Do you have a link to the process?

Clodius

I live in London, but I bought the machine from Bristol, equally hard water. I’ve been using a Lelit descaling filter and Tesco Ashbeck water with this machine and previous ones.

I just had some leaking, so I just did my best to make it as good as possible.

More on the steps I undertook are here https://coffeetime.freeflarum.com/d/3454-lelit-elizabeth-descaling-just-the-brew-boiler

Clodius

@NewyChris have a look at this video. Maybe the temperature sensor hasn’t been plugged in properly. The other thing that might be causing your problems is the safety thermostat (MC521)

NewyChris

Good video, thanks. I may well end up doing this myself. At this stage all the work has been done by the (former) Australian distributor of Lelit, so I am going to give them the benefit of the doubt. I wonder if they didn’t get a bad batch of sensors or something. Alternatively, my machine has a scale issue that is corrupting the sensors.

I don’t think it is the safety, as that would be tripping and turning off the boiler, would it not?

Clodius

Start with a descaling procedure as described here (limescale buildup could cause localized overheating)

https://sway.cloud.microsoft/qoXHjmMAg4DeFX8b

Also inspect all the connectors for looseness and oxidation (clean, tighten and recrimp).

Can you check the temperature with an external thermometer with a thermocouple probe if the temperature of the steam exiting the boiler varies in the same way as the PID?