Posted by: @cathoderay

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do you happen to know if Baxi is a Midea clone?

Yes, I think it is... I'm pretty sure someone on a recent podcast panel said that it was.

Posted by: @editor

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I'm pretty sure someone on a recent podcast panel said that it was.

And @cathyem1 - those images - thanks - confirm it is. The listed parameters are identical to the ones I have on my Midea badged wired controller.

In the first image, the important parameters are the water flow, which is a bit on the low side (mine in normally around 1.4m^3/h), if yours goes much lower you may get flow errors, the heat pump capacity which is its current (instantaneous) power output which was zero at the time you took the photo, ie the heat pump is off, not producing any heat, and power consum which is unit's lifetime energy consumption (in kWh) which is currently low because the unit has only recently been installed (and has done very little since then). Bear in mind the power/energy numbers are Midea/Baxi numbers - they may or may not have been massaged (the evidence suggests if they are, it is by not very much). Ignore the Room temp line, its meaningless.

In the next image you have T5 which is the DHW tank water temperature which is low - either the DHW heating never comes on, or if it does, you have used up all the hot water. TW_O and TW_I are the all important LWT (leaving water temperature) and the RWT (returning water temperature) respectively. These are probably just above room temp, and are one degree apart, suggesting the heat pump may have run a short while ago.

I still think there is something to be said for waiting until your supplier visits in case he turns out to be excellent and takes you through everything. There is also a risk he may take exception to a third party (me!) meddling in what he sees as his installation before he has had a chance to set things up! That said, if there is anything you would like to try and set up before he arrives, we can certainly have a go. At the end of the day, it is now your heat pump, not your supplier's, he is just contracted to make it work properly.  

@cathoderay Thank you for all your information. I don’t understand much of it, but I am keen to learn to make the system as efficient as possible.

I agree that waiting to see what the supplier says, how well he explains the system, and any tweaks he makes is essential. I will use the company for a service contract, so I don’t want to ruffle feathers unnecessarily. I will update you after his visit.

All I want, and I’m sure it’s the same for most ASHP owners, is to have the system as energy-efficient and cost-effective as possible. My husband is 77, and I have progressive multiple sclerosis, so we need the home to be warm in the winter, but we cannot afford to spend more money than necessary. We are at home for the majority of the day. Our Tomato Energy Lifestyle tariff starts on Monday, moving away from the British Gas EV tariff as it is cheaper, and BG is removing our gas meter on Tuesday 18th, so that will save us the standing charge for the gas. 

Your requirements (an effective and as efficient as possible heating system) are entirely reasonable, and that is what your supplier has contracted to provide.

Heat pumps do need a different way of doing things, but the basics are not complicated, even if the last time you did anything 'scientific' was more than half a century ago. My first reply to you original post covers most of the essentials, in essence, run the heat pump 'low and slow', and 'always on', and use weather compensation to control the heating level. That really is 95% of running a heat pump! Things like the LWT and RWT are just used to check it is running 'low and slow'.   

I agree, let's wait and see what your supplier comes up with.

@cathoderay I've been the one pushing for this new sustainable heating as my husband and I are 20 years apart in age. I think the poor man just wants to be warm without all the change 😉

Posted by: @cathyem1

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I think the poor man just wants to be warm without all the change

Very understandable! However, heat pumps can be more comfortable that traditional boiler heating for a number of reasons including:

1. Low and slow, always on means more steady heating (which we humans tend to like)

2. Low and slow, always on can reduce damp and condensation, sometimes dramatically so (as happened in my case, instead of rivers of water running down the windows especially in autumn, I now have virtually dry windows. Clothing and bedding also feels drier and less clammy.

Might be worth mentioning those benefits....  

@transparent the timer is linked to the immersion heater I believe. I'll check when I see the supplier on Monday.

Yes, more insulation is required. Another point to make on Monday.

It doesn't make sense to me that the immersion heater is controlled by a time clock, separate from the heat pump.

Every heat-pump approved for use in UK has a system to turn on the immersion-heater in order to raise the temperature of the DHW tank to 60°C, rather than the usual 45°C - 50°C.
This occurs about once per fortnight, and is a safety measure to prevent the growth of bacteria.
It's called the anti-legionella cycle.

For that to operate

• the immersion heater should be switched on/off only by the heat-pump itself
• the immersion heater's own (internal) thermostat must be set above 60°C (otherwise it'll never get up to temperature!)
• there must be a temperature sensor on the DHW tank which connects back to the heat-pump

So you wouldn't expect to see that time clock in the cupboard.

@transparent another one for the list!

Yes!

And this is why we like having photographs of installations.
We can spot things which you might not think to ask us!

Would you like to try posting a photo of the pipes at the back of your external unit...
... and where they enter the house through the external wall?  🙂 

Posted by: @transparent

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So you wouldn't expect to see that time clock in the cupboard.

I have exactly the same set up. Maybe it's a Midea/Midea clone, or possibly Freedom Heat Pumps thing.

I don't have it doing anything, it is just there in case the heat pump packs up, as a backup to provide domestic hot water. I have never persuaded myself that the risk of catching Legionaire's disease in a domestic setting outweighs the scalding risk of using anti-Legionella cycles and so I don't run one. Note that I am NOT giving medical advice, instead I am just reporting on a personal decision. Everyone must always make their own decision, based on their medical and other circumstances.