Vokera Excell 80SP

Anyone familiar with this combi (as subject)? A friend of mine has one and correct operation of the DHW side has become somewhat intermittent.

This boiler uses a purely hydro-mechanical method of operating the diverter valve: a differential pressure sensing thing with a large diaphragm senses flow in the CW feed and actuates a push-pin. The latter moves a pivoted lever, the other end of which operates the 3-port diverter valve. The diverter valve end of the lever should also operate a microswitch which provides a DHW demand signal to the PCB and fires the burner (if not already firing for CH demand).

Fault symptoms initially were no hot water unless the boiler was already firing. The lever was moving enough to operate the diverter (at least partially), but not quite far enough to operate the microswitch. An initial bodge cure was provided by bending the lever of the microswitch a tad. This lasted only a few days; same symptoms returned. I've replaced the microswitch as a precaution, but now find that the travel of the lever is grossly insufficient to operate it, and hot water (when firing for CH) tends to be lukewarm since, presumably, the diverter valve travel is also incomplete.

Clearly there is a problem in the hydraulic/mechanical system. But is the pressure sensor not pushing hard enough or is the diverter valve too stiff. To move the lever far enough by hand to operate the switch seems to need quite a lot of force - but I've no feeling for what is normal here. Is this a is known or common fault? The diaphragm for the pressure seems to be a commonly available spare - is that a clue? Is its replacement a straightforward procedure?

Any thoughts welcomed.

Reply to
Andy Wade
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In article , Andy Wade writes

I'm looking after one for a friend but that problem hasn't come up yet. In my searches I found the Gas-News forums, they seem to be oriented towards self help for the trade so plenty of detailed and technical replies, quite a bit on the Excell and the diverter gets plenty of mentions:

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manuals are readily available from the vokera site and the installer manual has good fault finding flows
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(needs flash), head for Installer > Product Info > Discontinued Products

There still seems to be plenty of spares around, google gives:

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the future, the electronics are v straightforward, watch for the solder joints on the CH and DHW setting pots breaking, also watch for mis- setting of the minimum gas rate, it's controlled by the oh too readily visible square headed shaft poking out of the gas valve and surrounded by the modulator coil, it just seems to draw people to it in an 'I wonder what this does' kind of way and you end up with the boiler flaming out on low rate or having no modulation at all. Not obvious from the manual is that it is basic step modulation, just high or low.

Good luck.

Reply to
fred

There could be two things wrong>

Firstly the diaphram is either punchured stopping it open correctly or stretched so it is going round the actuator disc not allowing it to move far enough or the valve pin is scaled and wants cleaning. niether are hard to do and it should be a cheap fix. try this to see if you have cured the fault... let the heating go cold and then run only water and see if the central heating flow pipe gets hot.. it should not.. this will tell you if the divertor is operating correctly. if the flow remains cold on the heating but the water is still luke warm you need to check the boiler heat exchanger temp. It should be around 82c if it is then the domestic heat exchanger is either blocked or scaled. hope this helps.

Reply to
gasman pete

I doubt that there's any problem with the heat exchanger. If you pull the lever all the way over manually then HW is fine, and the whole boiler was was working OK a few weeks ago. I did wonder about scaling of the pin though. I'll order a spare diaphragm, then strip it down and see what's to be found.

Yes, thanks for your reply - and Fred too for yours.

Reply to
Andy Wade

What was to be found was a very knackered diaphragm with a hole in it, and much rubbery material stuck to the inside surfaces of the metalwork. A good clean-up, new diaphragm and spot of silicone grease on the spindle appears to have effected a complete cure.

Reply to
Andy Wade

Result. Where did you get your spares, any online you could recommend or was it local?

Reply to
fred

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I've used them a few times now and they've always been speedy and reliable.

Reply to
Andy Wade

Thanks

Reply to
fred

Im looking for any Excell 80SP for breaking. I need a few plastic parts (the fascia etc...)so anyone ripping one out please let me know! Thank you!

Reply to
Gidsta

Before answering a 14 year old post from a broken website, please read and digest this:

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Reply to
Fredxx

You're wasting your time posting your smacky bottom messages.

Reply to
Dave W

Yes unless you post them on their forum many seem to mysteriously never get on there. If they do its probably better to merely tell them that the site does not seem to be year aware! Its odd that the powers that be do not filter mail to and from that heap of doggie do dos version of a mail server. Brian

Reply to
Brian Gaff (Sofa

And you?re not wasting your time?

It *may* be a waste of time but if it educates even a few HOH users it?s probably worthwhile. I?m glad that someone is taking the time and effort to try and educate users of that portal.

Tim

Reply to
Tim+

My posts do end up on the Home Owners website. They have banned some posters such as Rod Speed.

My experience is that most posters will generally want to see if they have stirred any interest, so I would expect a fair proportion to see my reply.

Reply to
Fredxx

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