Kamstrup Multical 403 Erratic flow readings

TrystanLea · 2023-08-22T16:12:43.279Z

Thanks @ajdunlop just re-read your original thread as well. Sounds like you managed to get an improvement before further air dislodged again and so back to square one? What are your options to get the installer to look at this / add further air vents say up at the unit itself? or to re-orient the heat meter with a good length of straight pipe before it?

Zarch · 2023-08-22T17:37:25.238Z

ajdunlop:

I also assume that reason the problem doesn’t happen until later in the hot water heat up as at higher temps that’s when more air bubbles are forming?

@marko made lots of great replies in my Sharky thread about cavitation and air bubbles etc.

Might be worth taking a look back through that?

Sharky 775 heat meter questions Hardware

E7 is air in flow pipe detected. Hotter water can hold less dissolved air. It will cavitate earlier. It’s also possible that entrained air in dhw is simply not clearing the coil ever. I can’t comment on plumbing other than to say this issue is nowhere near as prevalent in the district heading space. The manufacturer is following the mbus standard here so had already told you everything that you need to know there. The error values displayed are being incorrectly parsed by the mbus parser. Th…

ajdunlop · 2023-08-22T18:32:38.533Z

TrystanLea:

Thanks @ajdunlop just re-read your original thread as well. Sounds like you managed to get an improvement before further air dislodged again and so back to square one? What are your options to get the installer to look at this / add further air vents say up at the unit itself? or to re-orient the heat meter with a good length of straight pipe before it?

Yes when I first had the heat pump going I had it cutting out readings. After a bit or radiator bleeding and bringing up the pressure things improved (was still always a bit spiky later in the cycle) but looks to have gone backwards.

I believe my installer still has to come back to commission (after a few other electrical bits are done) so I’ll see if they are happy to move it then. There aren’t many good long sections without bends but a straight length that would probably be better than where it is now.

JohnT · 2023-08-25T08:54:31.868Z

Thank you for investigating this further and drawing some sensible conclusions. Just out of interested what numbers of heat meters are we talking about here? e.g. 50% of how many? I plan to ask Mark, our heating engineer, to bleed the system on his next visit, so will report back.

50% of kamstrup systems are not showing the issue, 22% of systems did show the issue early on but the issue has now resolved and 28% of systems still appear to show the issue to varying degrees.

TrystanLea · 2023-08-25T20:39:47.405Z

Hello @JohnT 34 working fine, 15 resolved and 19 still showing the issue (dont think most of these have tried to resolve the issue actively). Hope that helps

JohnT · 2023-08-30T15:10:17.933Z

Been a few days since I bled all radiators upstairs and downstairs. There was some air in one of the upstairs radiator. I’ve been round and done this twice now with a couple of days gap in between and DHW runs. Second time no air escaping just water. System at 1.9bar. Pump at 50% speed.

Attached a 2 runs for the DHW; 25th and 30th August respectively. Seems to be much better if I’m interpreting the data correctly. Seems rather erratic on the flow rates still.

25-08-2023-DHW-run-15mins-good1920×1537 138 KB

30-08-2023-DHW-run1920×1564 153 KB

glyn.hudson · 2023-09-01T22:56:44.762Z

Yes, that looks much better. There are still some erratic readings but at least this will have less impact on the energy reported rather than completely missing heat data! It will be interesting to see if over the coming weeks if you keep bleeding the radiators and keep the pressure high at around 2bar to see if the trapped air will dissipate.

JohnT · 2023-09-02T08:52:45.131Z

glyn.hudson:

There are still some erratic readings but at least this will have less impact on the energy reported rather than completely missing heat data! It will be interesting to see if over the coming weeks if you keep bleeding the radiators and keep the pressure high at around 2bar to see if the trapped air will dissipate.

Thanks Glynn. I’ve marked the Solution option in this thread. I will keep bleeding the system. Once the heating season kicks in that should make it easier to get out the remaining air.

Vinny · 2023-09-02T09:51:24.998Z

JohnT:

I will keep bleeding the system

Sorry but I can’t help it.

JohnT · 2023-09-02T09:58:22.478Z

Vinny:

Sorry but I can’t help it.

You are forgiven.
As an aside my mum was always tickled by the term “Where’s my bleeding key” when looking for the radiator bleed key.

Zarch · 2023-09-02T18:57:41.098Z

JohnT:

Been a few days since I bled all radiators upstairs and downstairs. There was some air in one of the upstairs radiator. I’ve been round and done this twice now with a couple of days gap in between and DHW runs. Second time no air escaping just water. System at 1.9bar. Pump at 50% speed.

Hi John

Ultimately, you wanna see if this is sorted by being able to run 100% DHW pump speed.
I found that running 50% pump speed was just a sticking plaster that masked the problem.

Plus, you should get better DHW performance running that pump with more flow rate.

JohnT · 2023-09-02T19:38:03.203Z

Zarch:

you wanna see if this is sorted by being able to run 100% DHW pump speed.
I found that running 50% pump speed was just a sticking plaster that masked the problem.

Plus, you should get better DHW performance running that pump with more flow rate.

Good point Mick sound advice.

I was in the loft today waiting for the DHW program to clicked in. As it started up I could clearly hear water gurgling through the 3 port valve, so I’m assuming there’s still more air in the system.

I will change the pump speed to 100% for the next runs. I’ve tried not to change too many things at once as it’s difficult to then track down what change made the difference in a positive or negative way.

glyn.hudson · 2023-09-04T14:50:37.221Z

Getting all the air out of the system is useful in other ways e.g. reduced corrosion, increased pump life span, increased efficiency and reduced noise, so it’s worthwhile to try and figure out what’s causing the air to be trapped and how it can be released.

@Zarch had a particularly tough time since he was using a plate heat exchanger on his Mixergy tank, apparently getting all the air out of a plate is tricky.

marko · 2023-09-11T17:30:50.028Z

The easiest way to get all the air out of a plate is to mount it horizontally (all outlets pointing up).

I don’t think that’s the best way to operate it; certainly with refrigerants undergoing phase change etc; but it shouldn’t be too bad in that orientation with water and water and at high flowrates only.

We’ve started recommending that all heat meters are on the flow side in these heat pump monitoring applications. You have greater static pressure in the flow sensing element this way; which delays the point where dissolved air decides to dissolve out.

(dissolved air being MUCH harder to kick out than basic trapped / entrained air)

[edited as I said heat out of a plate not air out of a plate - thanks Gwil for the spot]

ajdunlop · 2023-09-20T08:37:17.180Z

My installer was around to commission last week and I got them to move the meter onto a clearer run of pipe away from the magnetic filter and bypass valve.
Doing this introduced lots of air into the system that I have been bleeding out and the heating was on yesterday allowing air to get into radiators where I blead it off.

However the situation doesn’t look to have improved:

image1098×491 61.7 KB

Will just have to give it time and see what happens.
I can’t hear much air movement apart from a slight ‘tinkly’ sound that I could hear towards the end of a cycle. Makes me wonder if this is the dissolved air mentioned by others forming bubbles when at higher temperatures.
Surely there must be some way of getting this out, presumably it is getting redissolved when the water cools down.
Also surely there must be a reason that only a small number of us are experiencing this or is it just that lots of people haven’t noticed or cared too much because they have mainly been looking at heating cycles rather than DHW?

ajdunlop · 2023-09-20T08:40:39.505Z

Could it help to raise my DHW target temperature to something like 55 degrees (currently 48) for a couple of runs to get more of the dissolved air to be released and have a chance to escape?

marko · 2023-09-20T19:12:41.953Z

Get it all hot (on space heating), purge the air from rads, flip back and forth between heating / hot water to shift air into rads, purge the air from rads.

Bump up the static fill pressure. Then meters with flow sensor on the supply (rather than return) will experience higher static pressure and be less prone to air dissolving out etc.

Why don’t most experience this? Most don’t notice. Many use Sontex meters that are more robust to air but appear more vulnerable to muck.

glyn.hudson · 2023-09-20T22:46:01.528Z

Having AAVs (automatic air vents) installed at the highest points of your system is a big help to get rid of air, but you’ll probably still need to manually bleed rads for a few weeks to get all of it out. Could you post some photos of your system showing the location of the meter and the AAVS?

JohnT · 2023-09-28T14:12:32.797Z

Update: on my erratic flow rate readings on the Kamstrup 403 post solution implementation

Mark from JMR Heating came on 20th Sept and fitted 2 additional AAVs on the flow and return pipes.

IMG_68831920×1440 289 KB

I have been running the heating and hot water circuits and bleeding air from the radiators every few days. I bled some more out today - I’m a bleeding expert now!

Flow rate reporting is now becoming a lot more stable during heating runs. This is from the 23rd Sept.

Screenshot 2023-09-28 at 14.54.312218×1778 408 KB

DHW runs had always been the more erratic for reporting flow rates with the Kamstrup. It’s so much sbetter than it was, but as you can see there are still some fluctuations in the readings.

Screenshot 2023-09-28 at 11.54.521920×1554 154 KB

However, it’s a marked improvement and points to the fact that there is most likely still more air in the system.

ajdunlop · 2023-10-03T13:28:38.381Z

glyn.hudson:

Could you post some photos of your system showing the location of the meter and the AAVS?

Sorry for the slow response.

I’ve made a video of me pointing at things as I couldn’t really work out a way to show it all with photos (sorry for my boring voice and the mess of wires I haven’ sorted out yet).

I have wondered if sometimes air trapped in the coil floats its way up after the DHW heating cycle and gets trapped below the 3 port valve. Just that sometimes when I have manually changed the valve between heating and the tank I have heard air moving.
Maybe I need a the valve to be rotated 90 degrees with a bit of horizontal with a automatic bleed valve.

My hot water runs don’t seem to be getting better with time.

I did try upping the pressure from 2 bar to roughly 2 1/3bar a while back which seem to help the run that was currently happening and maybe the one after that but then went back to the flow rate reading dropping out.