Problem solving help please

[CakeBoy]

Chaps, your input would be gratefully received.

I will keep it short. Anna had a new rotary pump just before Christmas. I fear the pump failure was symptomatic of something else.

Her boiler pressure is set with the range 0.7-0.9 Bar. She brews fine. Water appears at the head instantly though there is a slight grumble from the pump that could either be a rattling spindle (the new pump has a loose spindle between the pump and motor whist the old one was fixed in the pump) or I fear a momentary dry running of the pump whilst it primes.

She is also losing boiler pressure whilst steaming. She used to stay in the 0.7-0.9 Bar range and steam all day. She now drops quickly to 0.5 Bar and struggles. Her recovery is also rather abrupt. We can't see any leaks and now wonder about the heating element and maybe scale on it though we doubt the latter.

The solenoid, anti-vac and fill probe have all been removed, cleaned and appear fine, though there anti-vac did appear to be leaking steam a little prior to cleaning. Anna has been descaled. The wand and tap nuts are tight.

Any thoughts please?

[GreenBean]

Hi Cakey, I hope that Anna misbehaving did not detract too much from your enjoyment of the Christmas festivities.

From what you describe I do not think the new noisy pump issue is related to the rapid loss of pressure when steaming. The most likely explanation would be the anti-vac valve stuck closed. This would stop the air escaping from the boiler on initial warm up and the air would be released when the steam wand was opened causing a rapid drop in boiler pressure.

You can test to see if this is the problem by letting the machine warm up then opening the steam wand and letting the pressure drop this will allow the air to escape. Let the machine warm up again to full boiler pressure. If you can now steam normally without a rapid drop in boiler pressure then you know the problem is air in the boiler due to the anti-vac valve being stuck closed.

[CakeBoy]

Hi GB

Bit hit and miss over Christmas, hope you and yours had a lovely time.

Thanks, we have just double checked and it seemd not. The anti-vac has been oit, stripped, descaled and rebuilt. It appears to be okay but perhaps it is not quite working properly.

The steam test takes her initially down to 0.5 Bar in some hurry, then slowly on down to 0.2 Bar in 20 to 30 seconds. She used to stay in her boiler cycling range regardless of what that was set at and just steam all day.

Letting her recover and then steaming again may yield a slightly better result but th same still occurs in a similar time frame.

We fear something complex is happening as She did the same before killing her pump, presumably through sucking air?

Your help s very much appreciated.

[lsjms]

Is the element light kicking on at it's usual point or has the deadband widened?

If so, I think you have gunk in the pipe between pstat & boiler..

If not you may be looking for damaged wiring or part failure of the element

[CakeBoy]

Hi Isjms, thanks

No, the deadband is still spot on 0.2 Bar regardless of pstat setting. We wondered about the element or scale on same, though she gets reguarly descaled. There is however dry coke like froth forming on the point where the element control box seats against the boiler. Maybe something to do with it?

[lsjms]

Helps point the finger!

2 leg element(4 terminal ends)? Sounds like you have only 50% element running. Can you confirm with a multimeter?

element control box ??? The relay/ contactor or do you mean the brain/control box? Photo?

[CakeBoy]

The connector on the element itself, sorry I was not at all clear there. No multimeter to hand but can probably get hold of one tomorrow. Pic to follow shortly

[CakeBoy]

Photo:

[lsjms]

Yuk

Get that cover off, looks like quite a lot of corrosion, I'm guessing one of the element terminals will be toast and it could be pretty messy in there.

[lsjms]

Posting from the future! Check the time....

[CakeBoy]

Woo spooky! Laptop time machine

Okay, will have a peep.

[CakeBoy]

Okay, photo:

[lsjms]

3 legs. I can't see any detail, any cracks in the elements ceramic insulation? If you cant see antthing obvious at fault in there then you are going to need a MMeter to procede with fault finding on the element.

Can't see what else it could be, boiler water level is normal right?

Is that just a single red powering all 3 legs?


Leccy off! Here be danger

[CakeBoy]

There appears to be no cracking but a little of the crud is on the base of one of the connections where the wire meets the connector. I don't know much about the element wiring but can describe it. There are six terminals. The left three are joined together by a plate spanning them and the right three are joined together by another plate. There is a brown wire to the left plate and a purple one to that on the right. The thinner grey wire from the coil in the picture runs into the middle of the element ceramics.

I am a bit unsure how to test this setup with a multimeter.

Leccy off, no free perms here!

[GreenBean]

...... I am a bit unsure how to test this setup with a multimeter.

Leccy off, no free perms here!

I do not have specific information for the L'Anna and do not have time at the moment to look it up but I assume the heating elements are rated for about 2.4 kW to keep the total load, with the pump running, under 3 kW for a standard 13 amp socket. If you check the actual rating you can adjust the following numbers accordingly.

The photo shows three elements connected in parallel that is each element is connected to the 240 volt supply. If you have a Kill A Watt type device then that may be the easiest way to see if an element has failed. With the heater on and the pump off the power should be about 2.4 kW. If one element has failed then it will be about 1.6 kW and if two have failed it will be about 0.8 kW.

If you do not have a Kill A Watt type device then you could test the resistance of the combined elements. First unplug the L'Anna and disconnect one of the wires to the elements so the readings are not affected by anything in the external circuit. Then read the resistance from one set of three connecting plates to the other. From Ohm's law the total resistance of all three elements in parallel should be about 24 ohms. If one element has failed it should be about 36 ohms and if two have failed about 73 ohms.

Good luck.