The Axioma Qalcosonic E4 heat flow meter in a newly installed heat pump + EmonHP Level 3 Monitoring kit is providing constant flow rate readings in a pumped variable speed flow.
From time to time the system circulating pump becomes very noisy and in wondering why I noticed that whenever the pump was running the flow meter was reporting a near steady 25 litres per minute flow rate regardless of the pump’s variable running speed. I had expected to see variable flow rates.
Air bubbles are an acknowledged cause of both pump noise and incorrect flow rate readings and extremely helpful advice on removing air from the system is provided online. In my situation however, these steps will require a visit from the installation contractor which I’m reserving for sorting out some other unrelated snagging operations
MEANWHILE - QUESTIONS
Thanks for any answers for a community newcomer …
Does anyone have any suggestion as to why the Qalcosonic E4 reports etiher a zero or a steady flow rate?
Is there a straightforward heat meter button pushing remedy I might try without risk of upsetting its (apparently correctly set) heat flow meter settings.
SYSTEM DETAILS
A Wilo Para STG 25-180/8-60 under iPWM control circulates untreated water between a Stiebel Eltron HPA-O 10.2 Trend HC 230 (R290) heat pump and the buffer tank of a Stiebel Eltron HSBC 220S integral cylinder (in which a 200litre DHW tank sits on top of the 100litre buffer, the buffer tank top is the base of the DDHW store - the buffer tank supports a second heat source, in this case a Viessmann solar thermal array).
also at the start of the DHW cycles there is often a little blip where it registers heat output while on hot water and it’s measuring a different flow rate at this point consistent with different pressure drop across the DHW tank compared to the emitter system, again suggesting the axioma is reading the flow rate correctly - apart from when it’s in air error of course!
Thank you Tristan. That is really helpful as it would seem to rule out an error in the Axiom flow readings.
The Axiom meter is monitoring flows to the pump that’s being controlled by Pulse Width Modulation provided by the Stiebel Eltron controller. Its changing noise level appears to confirm that it does change its speed (I’m trying to cure the problem of its excessive noise at certain times). I’m perplexed why flow rates aren’t changed according to the pump’s noise/speed.
POWER CHECK?
Separately from the electricity supplied to the heat pump, the Level 3 system is monitoring the electrical feed to the controller and three circulators: the main pump under iPWM control and the pumps for the radiator and the underfloor heating circuits, these pumps run 24/7.
I am unfamiliar with emonHP so don’t know where to look for the consumption pattern of that second electrical feed. Over 24 hours it should show relatively constant consumption until the iPWM kicks the variable speed pump into life, and off again.
Might I please be directed to that second electrical use data so that I can check if there are marginal fluctuations that could be related to either the programmed heating regime or other change in heat demand?
My level3 monitoring kit came with a single sdm120 electricity meter. All the electrical usage of all my Heat Pump gubbins is measured using that one circuit.
But it sounds like your heat pump is powered on a different circuit to your other circulation pumps
Did you order and install additional circuit meters with your level3 kit?
If not, then your secondary pumps etc that are powered from a circuit separate from the sdm120 on the HP circuit will be invisible to emonCMS.
So that I can compare our before and after seasonal kWh heating consumption the heat pump electricity consumption needed to be recorded separately from the circulating pumps’ consumption - the previous gas boiler had circulating pumps too.
This was an afterthought and our very accommodating contractor added a second SDM120 meter (along with a DHW Status Sensor) to our original Level 3 kit installation.
As a new user I am unfamiliar with emonHP and was asking where to view readings from that second SDM120.
Because of the availability of monitored data it’s been discovered that the setting for the modulating pump had been incorrect. Now the setting is correct the pump speed can be seen to vary. Excellent outcome for emonHP. Thanks all.
