Hi, I have recently had an 11KW Ecodan air source heat pump installed and don't really know if it is performing as it should. I guess to some extent we have to wait for some proper cold weather to see how it performs but I am struggling to understand what the reports in MelCloud are telling me. So we have 2 heat pump zones, an underfloor zone and a radiator zone. The underfloor zone is further divided into 3 zones or tracks each with its own analog room stat. The radiator zone is controlled by a Hive thermostat which we already had prior to the installation. The underfloor heating itself is less than ideal because it is not screeded in which would be the best way of doing it (might get that done at a later date but of course it will be costly and cause a lot of disruption). My main issue when looking at the MelCloud reports is that often the flow and return temperatures seem to be very similar, which seems odd to me. Having said that, if I look at the temperature guages at the underfloor heating manifold, the flow and return temperatures will often show a 10 degree difference.
The heatpump is working in "weather compensation" mode with and the flow temperature has not been increased from whatever the unit is setting it at. The radiator zone (hive thermostat) is set to 19 degrees for most of the time and 14 degrees between 10pm and 4am. The underfloor heating analog stats are set permantently to around 18/19 degrees. Am thinking of replacing them with digital programmable Heatmiser units so that I can set them up the same as the hive thermostat. Anyway, I can't work out why for a lot of the time the flow and return temperatures seem so very similar a lot of the time. I want there to a be a difference don't I so heat is lost to the building. Can someone maybe take a look at these reports and tell me whats going on?
Hi, I have recently had an 11KW Ecodan air source heat pump installed and don't really know if it is performing as it should. I guess to some extent we have to wait for some proper cold weather to see how it performs but I am struggling to understand what the reports in MelCloud are telling me. So we have 2 heat pump zones, an underfloor zone and a radiator zone. The underfloor zone is further divided into 3 zones or tracks each with its own analog room stat. The radiator zone is controlled by a Hive thermostat which we already had prior to the installation. The underfloor heating itself is less than ideal because it is not screeded in which would be the best way of doing it (might get that done at a later date but of course it will be costly and cause a lot of disruption). My main issue when looking at the MelCloud reports is that often the flow and return temperatures seem to be very similar, which seems odd to me. Having said that, if I look at the temperature guages at the underfloor heating manifold, the flow and return temperatures will often show a 10 degree difference.
The heatpump is working in "weather compensation" mode with and the flow temperature has not been increased from whatever the unit is setting it at. The radiator zone (hive thermostat) is set to 19 degrees for most of the time and 14 degrees between 10pm and 4am. The underfloor heating analog stats are set permantently to around 18/19 degrees. Am thinking of replacing them with digital programmable Heatmiser units so that I can set them up the same as the hive thermostat. Anyway, I can't work out why for a lot of the time the flow and return temperatures seem so very similar a lot of the time. I want there to a be a difference don't I so heat is lost to the building. Can someone maybe take a look at these reports and tell me whats going on?
Thanks
Check your water pump speed.
Your installer would not appear to be the most knowledgeable about heat pumps, or he would have advised you that heat pumps and heatmisers don't play well together.
I would also suggest that you check the settings of the Weather Compensation (WC) curve.
The installer didn’t recommend the Heatmiser. The thing is we want lower temperatures at night, the hive thermostat allows us to do just that, the analog wall thermostats for the underfloor zones don’t, so they are set to a constant 19 degrees which leaves us too warm at night.
I am hoping someone can explain what the graphs from MelCloud I have posted actually mean and if they are indicative of a problem.
This post was modified 6 months ago by cornwallsean
I am starting to understand more about the system I have now... I think!! So the graphs I originally posted, I think at that time there was only 1 zone active, our underfloor zone, and I think most of the flow was probably taking the "easy route" through the low loss header we have. I see you can buy low loss headers but our installer made one using copper pipe fittings (should I be dubious??). So it would make sense that the return temperature closely tracked the flow temp. What didn't seem right was how the flow temp would rise to 55 degrees. Changing the stat on the radiator zone so that is on at the same time as 1 track on the underfloor zone and things seem better.
Now there is a noticeable differential between flow and return temperatures and the temperature is lower (which is what I want... for best performance right?). Is my interpretation of the graph correct?
For maximum efficiency and lowest energy consumption the Leaving Water Temperature (LWT) should be kept as low as possible. To achieve this the system should be operated in correctly adjusted Weather Compensation (WC) mode or Auto Adaptation (AA) mode, with as many heater emitters (radiators and/or UFH) in use as possible throughout your home.
The heat pump will respond to the heating demand. The heating demand is how much thermal energy is being absorbed by the heat emitters. The loading on the heat emitters is dependent upon the Indoor Air Temperature (IAT) and the Outside Air Temperature (OAT) along with the maximum heating capacity of the heat emitters.
The Difference in Temperature (DT) between the LWT and the RWT will vary dependent upon the system loading and the water flow rate. Lowering the flow rate will increase the DT and vice versa.
Low loss headers can reduce overall system efficiency, particularly if the system is not correctly balanced.
I would suggest that you read through the numerous posts on the forum to get a better understanding about how heat pump systems should be operated and then post any further questions that you may have.
