New to the forum, not new to having an ASHP but new to the understanding of running it. Jump down to system part if you don’t want to read a story haha! 🤣
This recent winter snap has caused me to knuckle down on the heating system, the actual efficiency and the understanding of using it.
Giving up on contracted engineers coming in to say yeah you got some heat it’s fine, with no regard to efficiency or whole house system working properly. So I have a few questions that I hope you guys/gals will be able to help me with.
Firstly I moved into the army pad in ‘17, anyone that doesn’t know how a ‘March in’ works:
You get shown round by an accommodation officer (this was CarillionAmey…) and they show you the whole house ins and outs, give you a home pack(manuals), a damage report (any existing damage, if any, we can report straight away and on our March out you don’t get charged) etc.
Though when it came to the heating system it was the classic- Show the ASHP, show the boiler and said leave it all On and don’t touch it and just use the thermostats around the house.
Not knowing what the sketch with HPs and UFH is, meant for first 3 years I turned off the heating completely during spring/summer/autumn. Timing the hot water for night period. Switching the heating on a timed basis for when “Winter is Coming.” Back in the days when leccy was cheaper (was on Octopus Agile before wholesale shot and had to jump to Flexible).
System- Ecodan 5kw ASHP (2nd pump, more on that later)
Connected to FTC2 (old and bold) and a Danfoss Timer panel (no Danfoss master Thermostat??)
UFH from Warmafloor (god knows piping sizes!) with 2x 6 zone manifolds. Stats in every room!
House- End Terrace- 112 m2 built in 2012. All electric (no gas plumbing in sight)
EPC grade B with energy rated at 80kWh/m2 (out of date as this year though)
3 floors -Garage on ground floor with entrance hallway and utility room (boiler, pumps, controller etc) 1st floor- UFH manifold, raised back garden where the Ecodan ASHP is located.
2nd floor- 2nd UFH manifold
This whole estate (225-250 houses) that was built for us was all built 3/4bed houses all with UFH and ASHP (contractors rolling in it! Along with the owner that signed the RHI)
Fair to say usually families come and go dependent on the serving partners assignments. So being here 5 years and going to be for the foreseeable is brilliant. Though the estate is now in disarray, many houses are now “condemned” due to…. the heating systems. We don’t get shown by people that understand the heating system how to actually work it properly so it comes as no surprise a lot are now condemned.
We had a couple heating problems a year and half ago but luckily was in summer and was affecting the Hot water. Engineers deemed it was the ASHP and so changed it for like for like brand new Ecodan 5kw (yes free of charge)
Recent cold snap has made me dig into YouTube and Google about UFH and ASHPs, nearly watched every HeatGeek video so learned a lot in past week, but after paying £97 and £95 past 2 weeks. £305 for mid Nov’-mid Dec’. I know current climate means it’s tough but surely having a fairly modern home, decent insulation with UFH and HP means it should be fairly decent?
Currentsituation- Heating works ok on ground and 1st floor with on 0.8 bar (can’t increase with u pipe for some reason).
Heating does not work effectively on top floor, can’t heat above 16/17oC at 1.6bar and flow rates in manifold disappear soon as one stat downstairs calls for heat.
Recently- After watching many HeatGeeks made me pluck up courage to touch the boiler more than simply setting timers. I actually had to ‘hack’ FTC2 because Army/Contractors don’t want us fiddling the system. It was on Locked mode, nothing a good google of Ecodan manuals can’t fix 😎
Settings- I now have HW to heat 0130-0300hrs @ 47oC (down from 58oC) we generally have a big use so negates the Legionnaire risk.
Heating I have learned about Weather Compensating, and know the system only allows for this. Albeit a very basic Min/Max WC.
I have now reduced the heating to -2oC/40oC with 15oC/30oC.
It was at -3oC/48oC with 15oC/35oC..
I know understand HP with UFH is such a delicate system and is best run low and slow.
Questions- How much efficiency should I be really be expecting, am I right to say the system set up is bad and probably the installation is poor? And any little efficiency tips?
Best way to run the heating without having advanced settings that most people seem to have nowadays? Max out stats and use WC till house is comfy?
How can I improve the flow to top floor and raise flow rates in manifold? When top floor is calling and 2nd floor isn’t, the most flow in seems to only be 2L/min shared out
Lastly, I know it’s Winter but how the heck do you get the Cooling to switch on FTC2. In summer, the house is disgustingly hot.
Any questions, thanks for any help everyone, and glad I found this little forum!
Welcome to the forum. It would appear that you have already made a good start by turning up the thermostats and adjusting the WC curve and DHW setting.
Without being able to see the layout of your system I will have to make a few assumptions, which you can correct as necessary.
I assume that each of your UFH zones will have a water pump and mixing valve, which will be controlled by the thermostats. Do you have any form of buffer tank or low loss header between the heat pump and the UFH manifolds?
I'm not an expert on UFH but I do believe that the flow through the different pipe loops can be set at the manifolds. For maximum efficiency on a heat pump system it is best to operate with the lowest possible Leaving Water Temperature (LWT), but you also need to ensure that there is a good flow water around the system. That way the heat energy produced by the heat pump gets distributed around the system, so if any flow rates appear to be low then it may be useful to increase them. Obviously before making any changes make a note of all the original settings and only make one adjustment at a time and observe the result.
From the point of view of losing heating on the second floor when the first floor is operating, it may pay to monitor the temperatures on the various pipes to try to assess where the water is flowing under different operating conditions.
Thanks! Yeah did not feel right to turn up stats to turn down system 😅
I can take some photos of the layout in the morning, I guess that will help you and other members that know a lot more than I do, but hey we all start somewhere haha.
For the water pump and mixing valves per zone I’m unsure. But buffer tank/LLH I’m sure there is down in the utility. There is 3 water pumps down there too, which I feel is strange. Most set ups online have a pump between the Flow/Returns of the manifold and all mine are down on the ground floor… 😅
Yeah that sounds familiar, so tried to slightly adjust flow on manifold upstairs but they don’t react when down stairs is operating. The part about LWT is new though, I’ll need to read up about that.
Ahh yeah that’s a good idea to try see where flow is going, thanks! One engineer said, water goes to path of least resistance (correct) so can’t be helped (really?) I.E can’t heat upstairs while downstairs operates… surely I can somehow 😂
The LWT is the temperature of the water leaving the heat pump, the RWT is the temperature of the water being returned to the heat pump. Simples.
There is normally a 5C difference (Delta T) between LWT and RWT when the heat pump is working normally.
As you may have read in other posts, a buffer tank or low loss header can be a source of inefficiency in a heat pump system. I can explain in detail later.
This post was modified 2 years ago 2 times by Derek M
Ahh yeah got you, learned about the Delta T but didn’t know the LWT and RWT names but makes sense now.
Yeah have heard/read some things about them but like most the system I’m at baby steps 😂 I think there’s one but not sure if it’s just expansion vessels. I’ve taken photos of the system, and counted 8 stats to the 12 zones.
Is the mounted white tank maybe a buffer or LLH?
1st Floor manifold- living room (1) calling and was flowing at 2L/m
2nd floor manifold- bedroom 3 calling with 0L/m as per issue stated in OP.
Is it not meant to be level? And Pipes fully insulated?
@calzo21 if the upstairs is cold - have you tried adjusting the mixing value to add less colder water in?
12kW Midea ASHP - 8.4kw solar - 29kWh batteries
262m2 house in Hampshire
Current weather compensation: 47@-2 and 31@17
My current performance can be found - HERE
Heat pump calculator spreadsheet - HERE
@derek-m No problem, I posted lots of photos of the system after your last reply Derek but it’s still waiting moderation.
Here’s a close up of what I think is the mixing valve for 2nd floor manifold, there’s also one down in the utility room I’m guessing for the 1st floor manifold?
@derek-m No problem, I posted lots of photos of the system after your last reply Derek but it’s still waiting moderation.
Here’s a close up of what I think is the mixing valve for 2nd floor manifold, there’s also one down in the utility room I’m guessing for the 1st floor manifold?
Hi Cal,
Yes, I found all the photo's and have now approved.
The above is a differential pressure valve, though I am still trying to figure out what purpose it serves. Is there just one of these valves on the first floor manifold? If so, then its purpose could be to balance the flow rate to both the first and second floor manifolds.
So that I am not trying to 'teach my Granny to suck eggs', how knowledgeable are you when it comes to heating systems?
@derek-m This one is connected to the 2nd floor manifold, and there’s another down by the boiler on ground floor as pictured.
I’m going to say I’ve got basic knowledge, like said last night I’ve only started knuckling down on trying to understand the whole system and that’s 5 years with it 😅 don’t worry about me sucking eggs I’m used to it being in the Army 😂
@derek-m This one is connected to the 2nd floor manifold, and there’s another down by the boiler on ground floor as pictured.
I’m going to say I’ve got basic knowledge, like said last night I’ve only started knuckling down on trying to understand the whole system and that’s 5 years with it 😅 don’t worry about me sucking eggs I’m used to it being in the Army 😂
Okay, I will describe how I think that your system should operate for best efficiency, and then you can check around the system and see if it is working like that.
The heat pump is a heat energy producer, which gets some of its energy from the electrical supply, but the majority of the energy from the outside air. The heat pump draws air in at the rear and one side, and pushes cooler air out at the front. It is therefore important that there is a constant supply of fresh air that does not include the cooler air coming out at the front.
The heat energy is transported into your home via two pipes, the flow and return. These should be well insulated to prevent heat loss.
A heat pump system can provide both central heating (CH) and DHW, but normally does not heat both at the same time. In most instances the system is set to give priority to heating DHW in preference to CH. In your system you will notice some valves with white rectangular boxes on top, these are the control valves that divert the water flow from the heat pump to either the hot water cylinder or the heating system. The valve feeding the hot water cylinder should not be open at the same time as the one for the CH. These valves are easy to test by setting your controller to provide DHW heating and then switching it off.
The upper manifold for the UFH is the warm water supply, on which is installed the 6 flow regulators which have the red caps. The lower manifold for the UFH heating contains the 6 solenoid valves, which I assume are controlled by individual thermostats in the relevant rooms.
If you can provide photo's of the other items of equipment, pumps, valves etc. I will try to figure out what they are doing.
