Sharky 775 heat meter questions

Could you sell them separately, or else post a link whith where they are available from?

Can the be read by an ESP or Pi?


The Sharky I bought comes with pocket sensors and the 1/2" pockets. I’m planning on using some thermal paste in the pockets for better thermal transfer.

The Sharky manual says that sensors must have their tip in the middle of the pipe. While there will be some flow restriction / disturbance it won’t be very much.

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They come with Kamstrup heat meters, I’ll try and find out if they are available separately

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Does anyone know what the green washer thing that comes with the Sharky is for?

I expect it’s obvious but I can’t work it out! Manual seems unhelpful.

The green washers are the fibre washers to sit between the flow sensor and the flat face union couplings to seal them.

Try Alex Thornton at UK Metering for Kamstrup spares; they usually have good stock. Else if you don’t care for the parts being new I’ve probably got a bunch of these direct immersion probes in t he e might be useful one day corner that you can have for cost of post. PT500 type?

I think the “pocket sensors” shown above are suitable for direct immersion fwiw. You just need an o-ring and the special M10 nut to suit.

No. No they’re not. The similar looking 5.2 mm type are but not those. They’re meant for pockets.

It looks like @glyn.hudson also has his heat meter BEFORE both expansion vessel and the auto-air valve.

Whereas I have mine placed after both of those.

Is heat meter before expansion/auto valve a better way of doing it?
So you’re not dragging air out along the way as @marko suggests?

Possibly, but since my meter is a Sontex even if there were air pockets in there the reading would be effected. Have you tried increasing your system pressure up to 2bar? This fixed the same issue for:

I upped the pressure yesterday.

My manual dial showed 2bar, the Vaillant said 1.8 :man_shrugging:

I will keep and eye on it. I’m now also logging the raw power/flow feeds from the sharky before I curtail them with ‘max’ limits. I want to see what values the interface throws out in times of the sharky erroring and wonder if the interface can handle this better, as not to throw crazy wild data into the input and subsequent feed.

I’d still like to get it resolved properly though, ie heat meter placement.

And if a rejig/re-ordering of the expansion/AA and heat meter is the answer, then I’d do it as I want this to work flawlessly for the long haul.

And worst case, i’ve got a Sontex sat here in a box. :rofl:

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Quick hack: Bleed any air from the pipe up to the expansion vessel by cracking the union nut holding the pipe to the expansion vessel to release any air there and try again. May need to repeat a few times to purge all air from system.

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As per above, in your experience, is it better to have the heat meter before the expansion/auto valve? So you are avoiding the issue of dragging air from the expansion?

I’m thinking what would be the best way to rejig that small part of my return loop?
If it meant putting the heat meter first, i’d look at getting that done if it was best practice?

Dug this PT500 pair out of the parts bin - yours for postage donated to Paul Sartori? (

OK so we finally have our 7kw Vaillant Arotherm+ heat pump installed! Seems to be working well so far. Now need to get the Sharky up and running.

Quick question - I seem to recall reading somewhere that it is preferable to try and start the SDM120 elec meter and heat meter at ‘zero’ together.

Our SDM120 elec meter has been wired in before the Sharky so already couting total ASHP kWh used.

I presume this isn’t really an issue…

Both SDM120 and Sharky will always record values/counters internally on the devices regardless of whether connected to exernal sources.

When you hook each of them up to emoncms they’ll start transmitting the live data across MBUS / Modbus from that point. Nothing historical will go across these links, only live/new data.

Not sure if you can ‘reset’ a SDM120 back to zero? I can’t seem to see anything in the manual.
But unless that is important to you, it shouldn’t be any issue to emoncms.

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Thanks Mick that’s what I assumed. Only reason to keep them in sync then is to have historic total kWh against total heat which is kinda nice but not really necessary. I can always just write down the meter offset somewhere!

Another question for the experts - the Sharky meter from Stockshed came with Kamstrup Pt500 sensors. Not sure if this is a mistake or is a Pt500 sensor a standard thing and compatible across various meters?

They’re a standard item. PT500 is PT500. It’s only important that they’re a matched pair.

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Thanks Marko.

We’ve now had our heat pump in for a few weeks and heat pump and Sharky seeming to work well (at least values from the unit LCD seem sensible) - will hopefully get OEM up and running soon (kit ready just waiting for some pipework to be finished in the utility then I can wire it all up).

However my unit also has trouble during a hot water cycle, it also shows E-7. Only watched it do this once but seems to be temp related as it was working OK at max flow rate for a bit then fell over as temp increased.

This is a nominal 6m3/h unit running at 1.2m3/h (so ‘low’ flow rate for that unit size) and it’s on a nice straight 28mm run.

Once I’ve got the continuous monitoring up I’ll try and pin down exactly when it falls over.

Funnily enough, my Sharky had another 15 minute drop out last night. First time in over 3 weeks.
No rhyme or reason to it when it does or doesn’t happen.

Even though I limit the data going into the emoncms feed, it still skews data as normally the second half of the DHW run normally kicks out around 5kW.

Super frustrating!! :slightly_frowning_face:

Ah so yours is usually OK over a whole DHW cycle but just ocassionally falls over?