I changed the main title of the thread since I have moved into a complete rebuild and have questions that would pertain to other machines.

So... after 10 years without a glitch it's time to do some heavy maintenance on my Techno V2.
The hot water valve has been sticking for a while and the steam wand is starting to do the same. Last week the brew temp was very erratic and the motor or pump has started to make a clicking noise. ( I suspect it's a motor bearing.) So... time to play repair man!
My first question is about the solenoid coils. The Techno manual states that the resistance between 2 leads on the coil should be 900 (at 2K setting on the multi meter. 2 of the coils are reading at 889 and 933. Are these readings far enough out of spec to warrant replacing?
If not, only one of the 4 is a 3 way (all Parker) and I've been able to find the mechanical component for that at Cafe Parts, but they don't list the 2 way component separately, only the coil/component combo. Are there any other sources or should I stop being cheap and buy the combo? I've found a bit of lovely black grunge in them despite my water treatment and filtering so I think rather than cleaning them replacing the mechanical valve is the way to go. Any guidance will be appreciated!

Great machine! I've had one that kept me very happy for 14 years before I had the urge to upgrade.

Sounds like you've got a fair bit of maintenance to do. Replace the solenoids (get the combos), and especially the one that controls the transfer of water from the brew boiler to the steam boiler.

Replace the temp probe on coffee boiler and probably do the same for the steam boiler.

The pump motor has a weep hole that gets clogged up over many years, and then the motor bearing starts to rust and make noise. If its early on in the clicking sounds you can pull it apart, clean and re-lube it and you will be all set for another decade.

Hello, Scott

By coincidence, my Techno did a glitch yesterday morning. Tripped out the RCD just at the point where it was calling for water to top up the steam boiler.

Took the top and side covers off, and found that the brew water to steam boiler solenoid valve had leaked internally, and corroded then shorted out the solenoid itself.

Fortunately, a while ago I came across a used Techno that needed a fair amount of work to get it back up and running, but I bought it for spares, so have cannibalised that for a replacement valve. I did completely dismantle that machine - disassembled and descaled the boilers, replaced all o-rings and seals etc. with a view to putting it back into service. It is at the point where all it needs is a new pump (and now a new solenoid valve....) It's been at that point for quite some time though

In the past I have had problems with the hot water valve, which turned out to be small amount of scale. Even though my water is pretty soft, over time because I hadn't used the hot water draw-off but had steamed a lot, I think the minerals which are present had concentrated and caused the problem. Solution was fairly easy - remove valve, soak the business end in descale solution, then a bit of very careful manual cleaning once the scale had been softened. I now routinely draw off hot water to keep the scale concentration down.

You can buy the valve part separately, and the coil resistances sound within OK limits. I had tracked down a supplier of the valve part, but just looked and I can't find the bookmark. However, they are standard parker-lucifer valves widely used in all sorts of machines. There is a reference code engraved into the side of the valve part itself, so googling based on that would be a good start. There is also a guy here in the UK who sells a service kit for the mechanical valve part - very cheap. I haven't tried to service one myself, but may have to now. (Edit to add link) - http://www.spanglefish.com/AvicennasSol ... eid=384585

I'd agree with Kipp. The weep hole under the motor/pump connection can corrode and clog if the pump starts to leak at the bearing, and water can get into the motor bearing. Not just a Techno issue - pretty par for the course with conventional rotary pumps and motors.The bearing is a standard size (can't remember exactly, but it will be engraved on the bearing itself if you can remove it). Replacing it is easy once you have the old one out, and the motor casing splits for easy access.

The steam boiler and coffee boiler temp probes are identical, and with a bit of searching you should be able to find them if you really need them, but personally I wouldn't routinely replace them unless they are significantly outside the spec.. They screw in with a bit of loctite thread sealer (not locker). Beware, though - I found that the screw thread size in the 2 machines differs even though they are only a few serial numbers apart.

You can check out the existing thermistors with a meter - temp/resistance values are given in the Techno book - I wouldn't worry too much it they are a little off.

Generally, the Techno looks pretty daunting, but they are well laid out, exceptionally well built to commercial standards, and as a result are easy to work on. Many of the parts that may need replacement over time are industry standard components. If you have the Techno book, with a bit of research you can find all the seals, O-rings etc. too as they helpfully give you dimensions and specs.. About the only Reneka-specific parts are likely to be the heater coils and the brainbox. Both still available last time I looked, and the brainbox itself has a lot of standard components such as relays - only issue is likely to be the chip - I'm hoping if ever I need to get that fixed I can get the other one cloned !

Well worth sorting out, and after 10 years it doesn't owe you too much, so I reckon it's worth spending a bit to give it a new lease of life.

Thanks Rob and Chris! I checked the resistance of both temp probes at 3 different hot water temp and they are both off. One approx. 15+- degrees Celsius so I'm planning to replace them both. I contacted eevad.com and am awaiting a reply. Due to the cost I would rather find a source in the US.
Still searching for the 2 way solenoid components and if either of you has a lead please let me know. I think I'd rather make my life a bit easier and not try to rebuild the valve. Do either of you know what type of epode safe lubricant I should use?

I plan to take the heating elements out to descale the boilers. Is it necessary to remove them from the top block, or does going in from the bottom with the machine upside down give enough access? Lastly the manual warns not to use acid to clean the o-ring seat for the element, instead to light land with 400 grit. Is this the same for the boiler interior? Thanks for the guidance!

Hello, Scott.

The heating elements are a permanently fixed part of the brass base of the boilers.

Machine upside down (as you know - it's heavy !) remove the bottom panels and you can take the boiler bases off. I suspect the caution about not using acid is to avoid the chance of pitting the groove that the O-ring sits in, giving the possibility of leaks, although I don't see how you can use a descaler solution without it going into the grooves. I did use descaler, but then cleaned up lightly with fine abrasive paper. The boiler walls are actually simple copper tubes, and I suppose the same caution should apply to the very bottom of them as that is also a mating surface for the O-rings. By the way, if you feel you'd like to replace them while you are at it, they are Viton Size BS340 (metric 85.09 ID x 5.33 C/S). Readily available on ebay. You need some Viton friendly Silicone grease when reassembling - easy to get hold of as it's a standard plumbing product. (The note in the book about EDPM is out of date - they were replaced with Viton after some early failures due to chlorine compounds in water). Might be a good idea to replace the spring washers too while you are at it.

As far as valves are concerned, still can't trace the supplier I thought would sell the valve body only, but the complete units may not be that much more expensive anyway - I'm in the UK and the solenoids themselves are about £15-20 here.

Sorry - don't understand what you mean by "epode safe" lubricant ? If you're referring to the thread sealant for the thermistors, Reneka use Loctite 577 when assembling the machines. I guess you could use PTFE tape, but it can shred easily and get inside, so I prefer to stick to liquid thread sealant.


EDIT - the motor bearing is a standard 6202Z - easy to get and very cheap.

Epod safe.... auto correct for "EPDM safe".

Great info and helpful, thank you.
eevad has the heating elements and the boiler temp probes so I'll go that route for the those.
Still checking stateside for all the O rings etc.
Is there a way to check the viability of heating elements once they are removed?

You can probably get a good idea about the heater coils from a visual inspection (they shouldn't have any bursts or obvious lumps). Reneka spec the heaters in mine to be 1800w, but assuming you have a 110/115v version, I think they may be 1300w. If so, from ohms law you should see a resistance across the terminals of ~10ohms.

You can also check that there is no leakage to earth by turning up the resistance value on your meter, and checking for any continuity between the terminals and the brass base. Really a professional Megger tester is needed to be 100% certain, but if the machine has been running on RCD (GFCI to you ?)protected circuits without any tripping problem I guess they should be OK. Are you thinking of changing them out just as a matter of preventative maintenance or are they failing to heat ? Other than a visual inspection, I don't know how you can ascertain the "life left in them" - I imagine most heaters of this type fail because of damage/low water levels etc. or slight leaks which cause low level earth leakage.

It would be worth cleaning the terminals and checking the tightness of the push-on connectors while you're at it - there's going to be a fair amount of current running through them in the 110v version.

I got all the O-rings I needed from ebay suppliers in the UK - Although Reneka specify the sizes in metric, they are actually imperial BS sizes - I reckon you should be OK to get them in the US, but if not airmail wouldn't cost much.

***Just checked, and all mine and the silicone grease came from sealforce.co.uk (website directs you to their ebay shop I think).

Back to the solenoid valves - if it were me, I'd try just descaling them and seeing if that sorts things out. They have fairly small orifices, and can get clogged easily by even small amounts of scale. You can get at the seat easier if you unscrew the nut from the brass base plate and the piston parts then pulls away - they can be tough (very ) to unscrew though - and make sure the thin O-ring doesn't get damaged when you put them back together. The website I listed in an earlier post shows an exploded view of the assembly.

Keep us posted as to how you get on.

Thanks Rob. Actually I have the 230 version, Do you have the conversion sizes for the boiler O rings and the copper washers for the temp probes? For the boiler O ring it's listed as: D85,09X5,33.

Hello, Scott

As noted earlier - the boiler O-ring although specified as a metric measurement is actually imperial size BS340 (dimension is 3.375" x 0.21", but search for BS340 and you'll find exactly that).

e.g. on here if you select BS340 in the size box

http://www.ebay.co.uk/itm/IMPERIAL-SIZE ... dLOk7CJ4oA

The copper washers - I can't honestly recall if they are listed with a spec - but they are simple crush washers and the exact dimension isn't too critical. Provided they will fit fairly snug over the thread of the thermistor and you use the right thread sealant they will be fine. It isn't good practice to use the old ones but you'd probably find they would be OK too.

From a quick calculation - 1800w 230v heaters should be just over ~29 ohms.

My Reneka teardown continues. I felt rather than just replacing the temp probes that were testing out of spec and the solenoid components I'd go ahead and do a full overhaul. I use a whole house water softener (sodium) as well as 2 in line filters for the Techno and I thought the scale build up would be medium. When I removed the boiler bases to check the elements I was surprised to find a uniform black coating on the elements and the boilers. ON the elements it has a pronounced smell of burnt wood. Has anyone seen this before? I did a search and found one brief thread on CG but it wasn't very informative.