I’ve seen other comments about Heat Meter errors due to air in the system, I’m having a similar error but only when the flow temperature exceeds 33C during hot water heating. I’ve run the heat pump, Daikin 11kW, in heating mode with the flow up to 55C with no error.
As far as I can see the system pressure is the same for hot water and heating.
There are automatic air vents at all high points in the system.
The flow rate is about 27l/min when the error occurs and is the same when the heating flow temp exceeds 33C in heating mode with no error.
Any ideas would be appreciated.
Hi Marko, thanks for responding. I’d lowered the system pressure and run the heating flow temperature up to 55C thinking that would bring out the dissolved air which would then leave the system via the auto air vents. There has never been a problem with the heat meter with the heating running, only when the tank water is being heated. I was hoping there was some reason for the error when heating the tank only.
Auto air vents do not drop the velocity low enough for entrained air to exit the system.
Pour yourself a pint of Guinness. The “auto air vent” (the flow is open to the air as it comes out of the tap) does not remove all the bubbles. You need to wait for it to enter the radiator (pint glass) and then wait for the entrained air to rise ot the top and be bled through the bleed valve on the radiator.
I suspect it appears when heating the tank because there’s nowhere for that entrained air to exist the water when in hot water mode vs space heating mode (where it can chill out in the radiators).
A quick update. It took a while, and a number of tries, but I finally got the air out of the system and the heat meter is working. I found that the Daikin Altherma has an air purge sequence, I ran that a few times with high flow temperature and low system pressure. Thanks for you advice.
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Hi Alan, I have exactly the same problem with the heat meter on hot water cycle with the same model of heat pump. As I read it the air purge sequence only runs with the heat pump off, so I assume that your reference to high flow temperature and low pressure was separate to the purge cycle. Did you just disable the weather curve and set a temperature and how long did you run it for? Also what pressure did you drop the system to. I can then have a bash with my system. Thanks
Hi Stuart. I am no means an expert, I followed the OEM advice on removing air from the system.
System pressure reduced to 0.7bar.
My heat meter was going into an error state when heating the tank at about 44C, in ‘heating’ I set the flow temperature so that it reached 55C.
I’m pretty sure I did this by configuring the heatpump to ‘setpoint’ mode and setting the leaving water temperature to 55C, you can set the LWT temperature in the Onecta app.
I left the system running for about an hour after the flow temperature exceeded 44C. Bleeding the radiators once or twice during this time, the only radiators I got any air out of were the towel radiators on the first floor.
I then turned OFF ‘heating’ and ‘tank’ and ran the air purge cycle a couple of times, takes about half an hour to complete each time. Removing any air in the radiators after each sequence.
I re-pressurised the system to about 1.6bar and haven’t had any problems with the heat meter since.
Hope this helps.
Alan
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Hi Alan
Thanks for the response, one more question if I may, how did you reduce the pressure to 0.7 via a radiator bleed valve or the fill point on the system? Thanks again for your detailed response.
Stuart
I opened up the fill point with a bucket underneath, be careful to do it slowly as it spurts out.