My DIY installed Vaillant AroTherm Plus is now LIVE

championc

Live link to my system data - https://emoncms.org/app/view?name=championc&readkey=5e5a2bd11d69740be46a55e1793e551d

Well, after months of planning, research (between blogs, FB posts and YT videos), my Vaillant AroTherm + is now Live and up and running. While there is no Irish support, Vaillant Technical Dept in the UK have been very helpful with queries, and the UK FB group is very active, with several of the prominent YouTuber installers and users on there too. And of course, the Vaillant is always up there at the top of the www.heatpumpmonitor.org charts. The potential for running the AroTherm at higher temperatures, given that it’s R290 Propane based, meant that I could, in theory, run at gas boiler temperatures, if push comes to shove.

Overall, it has been a fairly painless experience.

We have a 3 bed Semi-D in Sth Dublin. We currently have a Vaillant Combi non-condensing non-modulating Gas boiler (so only around 60 – 65% efficient). I figured that evening running the AroTherm + at high temperatures, I would still have better efficiency. We also have a 30 Tube Kingspan Solarmax solar tubes installation since 2012. The tank has no spare coils and with the Kingspan working very well, it made sense to leave well enough alone.

Last November, I started using the MyEnergi Eddi to heat water to 60 deg overnight (on 5c/kWh Pinergy was a no-brainer). The tubes did an additional topup during the day on good days. If necessary, I could boost with the MyEnergi app in the evening if required. This meant I could stop using Gas and the Combi for DHW, and that worked very successfully over last winter. I had also lowered the CH Max flow temp as a way of understanding how a lower rads temperature might work out.

Therefore, the DHW requirement (and associated potential pipework) was removed completely from the plan. We currently use the Tado system with electronic TRV’s on all rads. We don’t heat all rads all of the time currently, but I am open to including more usage of ones which are currently less used. While efficiency is important, I want to run economically (even at the expense of efficiency). With no UFH, it made sense not to install a buffer tank. With sufficient capacity in the rads for defrosting too, there was no need to have to consider adding a volumizer either.

So the AroTherm flow and return would simply be T’d into the existing rads circuits.

I started with doing a heatloss calculation using https://heatpunk.co.uk and concluded I needed a 5kW unit, especially since I knew I still wouldn’t be heating the whole house constantly. Mind you, I was pretty certain of this size, based on blogs and YT videos for similar properties.

The first decision was the outdoor unit location. I had considered locating it in the side passageway, backing straight onto the wall of the combi. But it would have been blowing straight onto the neighbours house side wall, and would have narrowed the access considerably, since I will likely wrap the house next year, and so that would reduce the gap by a further 100mm. Airflow between both houses wouldn’t have been great either. So I went with the back garden, backing onto the boundary wall. I used M10 bolts screwed into zebedee’s for mounting and levelling. It is very important for the unit to be perfectly horizontal and vertical is all directions

The next decision was the arrangements of the pipework accessories. I got an Inta 1 ¼” to 1” valve for the flow, and an Impel 1” Filter & Mag valve on the return after a 1 ¼” to 1” reducer, with 1” Flexi hoses. I also got a 1” Anti-Freeze valve and a 1” Fill & Flush valve ( https://www.heiz24.de/Flushing-and-filling-unit-DN-25-1-internal-thread-2xKFE-12-NEW - a fantasic buy). I ended up putting the Filter, Anti-Freeze and Fill & Flush in series, after the Flexi hose.

Threaded joints are an absolute nightmare. However, when in Chadwicks, a Polish customer recommended Sellador thread locker. It was absolutely brilliant. So no tape anywhere – used this on ALL threaded joints.

From there, it was 1” copper all the way into the house. The pipes are lagged with Primary Pro insulation, which took some amount of tracking down to get (https://spares-direct.co.uk in Belfast). But it is far superior to the €1 per meter crap.

Inside the house, a pair of 1” x ¾” x ¾” 318’s linked the new 1” incommer into the upstairs and downstairs ¾” circuits. My main sitting room and hall rads branched off the dining room, over ½” pipes. I needed to add another rad into the sitting room, so this section of pipework had to be upgraded to ¾” or I could have ended up with flow issues. So while it was a pain, it was the proper thing to do.

So a last word on the Copper pipework. I am sorry I didn’t get “tectite” ( https://www.pipelife.ie/plumbing-systems/plumbing-heating-fittings/tectite.html ) push fittings.

The 1” compression joints were an absolute nightmare to seal fully. I had to use PTFE tape on several of the olives. The Fill & Flush became invaluable, being able to pressurise and leak-test pipe sections (once you capped off both ends and have a pressure gauge connected), or being able to almost flush the whole system through at will, especially to flush through a single rad if required (by closing all others).

I also bought Climaflex for insulating the indoor underfloor pipework https://www.amazon.co.uk/Climaflex-Pipe-Insulation-Foam-Lagging/dp/B07FMC58NB

The electrical connections are very straight forward. There are two wires needed for the outdoor unit – a 2.5mm T&E for the AC power, and a 2 wire 0.75mm cable for the eBus, linked back to where you locate the indoor controller.

I bought the SensoComfort Wireless Controller VRC 720f/3, who’s receiver is also linked to the ebus. I also bought an https://ebusd.de dongle, to extract all of the data locally from the system, for feeding into Home Assistant (and to upload data to heatpumpmonitor.org). It is USB powered, which I powered from a mains to USB adapter https://www.aliexpress.com/item/1005007009749779.html?channel=twinner , which I then buried inside the controller itself. I ran a spare Cat5 out to the outdoor unit, but I don’t see an immediate need for it.

I also linked my TADO Extension Kit controller to a port on the indoor controller, which enables the TADO to control the On/Off of the Heat Pump. The Extension Kit can do a Potential Free NO or NC connection.

As a cheap extra option, while doing the install, I bought and installed the Cooling Plug to enable to cooling function of the unit. This one is about £7 (part No. 0020266328) and is officially for a Vaillant Gas Boiler, but it works perfectly. The official AroTherm one is over £300 – go figure !!!

10-10-20

Hi ya, well done.

So did you have to get somebody in to gas the unit or how did that work?

graememk

https://www.boards.ie/discussion/comment/122671894#Comment_122671894

It comes prefilled, as it's a monobloc.

The refrigerant never leaves the heatpump

Paul Kiernan

Good job, championc. So are the boiler and heatpump both connected in parallel to the heating circuit? Or did you disconnect the boiler? Do you still have option of using the combi for DHW and if so how is it tied into the EDDI/Tubes setup?

championc

https://www.boards.ie/discussion/comment/122672064#Comment_122672064

It is paralleled, with level / disconnects on the flow and return, so those can easily be reopened and the levers to the heat pump closed off.

However, it became apparent on day one, that it had no problem whatsoever reaching 50 Deg or more in the circuit. But of course, this was quite easy with no stupid buffer tank to worry about. So I could absolutely run this like a gas boiler. Yes, it wouldn't be efficient, but it will do it.

On that basis, the gas boiler no longer has power.

As I said in the post, the DHW is completely separate. It has it's own 140l tank in the attic and is heated with the Eddi on night rate and the tubes on good days. I might need to boost it 5 days a year during the day. That small bit of power can come from my batteries

THE ALM

Great job championc.

Have a Viessmann just gone live last week so will be interesting to see the data of the two units. I have a bit of tweaking to do regards the setup and the weather compensation but think I am about where I want to be.

championc

@10-10-20 The flow and return pipes from the rads run to the outdoor unit, into a heat exchanger inside the unit. So the units' circuit is tiny.

The Vaillant uses R290 Propane, and apparently it's only a cup full of it.

championc

https://www.boards.ie/discussion/comment/122672719#Comment_122672719

It's certainly worth getting your data up on heatpumpmonitor.org (you don't have to make it public). You can visually see, at a glance, what it's doing and when. Yes, you can see it in Home Assistant too I'm sure, but this is nice and clean, for only a few quid per year

10-10-20

It is paralleled, with level / disconnects on the flow and return, so those can easily be reopened and the levers to the heat pump closed off.

…

On that basis, the gas boiler no longer has power.

Yes, needs to be electrically isolated as well as by at least one valve (though you could say that having two valves seals it off too well and leaves the heat-exchanger prone to frost damage). If it's not electrically isolated then the frost protection cycle could start up on a sealed circuit and cause the PRV to release.

championc

Well won't be an issue, as I ain't going back now. Bibwould happily disconnect the gas fully in the morning.

Our Combi was non-condensing non-modulating, so likely only around 65% efficient at best. So a COP of even 2 is a total plus for me.

championc

Not the best of comparisons yet, but an indication of what I hope is to come. We used 45kWh of electricity, delivering 181kWh of heat.

In September last year, we used 425kWh of gas. So looking back at TADO graphs, we turned on the heating on 15 Sept 2023. The Vaillant went live on 14 Sept 2024, although it was subsequently off for about 4 days last week adding another rad

10-10-20

https://www.boards.ie/discussion/comment/122672989#Comment_122672989

Cognisant of the fact that you'll be further insulating the house next year, did the house require much work in the way of increasing the rad sizes for the lower delta-T? I presume you were originally spec'd for a delta-T of 50C to 60C, so are now working off what - 35C delta-T?

Paul Kiernan

https://www.boards.ie/discussion/comment/122672713#Comment_122672713

So the Vaillant has everything needed to drive the heating e.g. pump, expansion vessel (things that would be in your combi!)? So you can just connect to flow/return and Bob's your uncle.

What do you mean when you say "you could run it like a boiler, but it wouldn't be efficient"? I presume you mean you don't turn it on when it's cold and turn it off when it's hot but rather run it constantly at a steady temperature?

championc

https://www.boards.ie/discussion/comment/122673172#Comment_122673172

Heatpunk confirmed my current rads, except the sitting room, would work at a design temp of 45°c at -5°c.

In addition, the sitting room rad was backing onto the hallway (easier for the plumbers at the time) rather than being located under a window. So I was almost happy to have the excuse to do it properly, and put one under the window.

In fairness, it's a huge window, and the window sill is about 37cm off the floor, so there wouldn't have been room for a proper rad. I added a 2m x 0.3m K2, which is now buckets for the room.

championc

The unit has a pump inside and some form of automatic air vent. But I had to add my own external expansion tank and AAV valve too.

By saying I could run it like a boiler, I meant running it at conventional gas boiler temperatures. Only heating rads water is pretty quick.

And as I mentioned, I have it linked to my TADO. The TADO controls the call for heat. So you can see from the data that the heat pump is off from 23:00 till 09:00 daily

Jonathan

Can you sketch the rough layout of HP, garden and the pipe run to the house? Do your flow and return pipes cross the side passage (assuming you have one)? My boiler is vented into the side passage way so trying to get pipes to there would be a bit tricky. And mounting a HP in the side passage itself would surely lead to microclimating (and a pain trying to get past with the bikes/bins).

championc

https://www.boards.ie/discussion/comment/122673728#Comment_122673728

The gas boiler backed onto the side passage of our Semi-D, about half way along.

So the pipes went back 3m, across the door of the side gate, and then a long the side of the back garden wall.

The house faces south, so it faces East, across the back of the house.

Look at the piping pic in the post, and it will make perfect sense

10-10-20

Where did you purchase the Vaillant from, championc?

championc

Secon Renewables in the UK. They arranged the courier / pallet shipment. Said they were well used to sending stuff to Ireland

Jonathan

https://www.boards.ie/discussion/comment/122673829#Comment_122673829

You'll have to excuse the crap drawing, but where is your side gate? Is it location 1 or location 2? Mine is in location 1, so I'd have to follow the red pipe route, or else get decking or something to get pipe work across the path at location 2.

championc

Like 2, but flip the whole pic on the horizontal. And both pipes side by side, flow and return

I'll draw it in the morning

10-10-20

Take a photo and have a dog in it for scale. 😀

championc

@Jonathan

Paul Kiernan

https://www.boards.ie/discussion/comment/122673728#Comment_122673728

One potential installer (i.e. very expensive quote giver!) told me that they usually install the HP high on the side passage wall so that (i) it's higher than the typical 2m boundary wall for good air flow and (ii) you can pass underneath with your bikes, wheelbarrow, etc.

championc

Wouldn't like that. You cannot escape the vibrations, however small, being into your walls. And if you want to wrap the house later.

The smallest of droning sounds would be heard inside

10-10-20

https://www.boards.ie/discussion/comment/122676714#Comment_122676714

Fair points.

championc

This heatwave is playing havoc with my testing / tuning. Maybe it's a nice complaint 😂

THE ALM

https://www.boards.ie/discussion/comment/122694327#Comment_122694327

Same, since going in it has been fairly mild although getting cooler at the end of the week.

I have, what I think, are low settings but the house is a bit warm for me. Will leave as is for now and see how it copes with the temps dropping this week.

As you mentioned earlier, I am working on the heatpumpmonitor side of things and emoncms via home assistant. Unfortunately the Viessmann free API does not expose the heat pump energy output so I am having to create a sensor and manually input the data for now.

Appear to be averaging a COP of 5.2 so can't complain yet.

championc

Now us the time to play to with the weather compensation curve value, and the max flow temp at maybe 0 or -5 (or whatever way Veissmann does it). But yes, COP of 5.2 is great news, assuming my you are using maybe less than 5kWh/day ?

THE ALM

https://www.boards.ie/discussion/comment/122698425#Comment_122698425

Averaging about 4kWh/day at the minute with a flow temp of 36° at 0°.

Still playing with it but will leave it at that to see how the rest of the week goes.

Recommendation is for a higher flow temp for rads so we will see.

championc

https://www.boards.ie/discussion/comment/122698637#Comment_122698637

"Recommendation for higher flow temp" 🤔

I think that would give a more spikey temp. You obviously want heat being added to equal heat being lost.

The rads / flow should be based on the outside temperature, assuming an outdoor sensor / thermostat was fitted. So I wouldn't expect any system to have a set flow temp. Otherwise, it would be acting like a traditional gas boiler.

THE ALM

https://www.boards.ie/discussion/comment/122699056#Comment_122699056

They mean in terms of their weather curve and being 40° at 0°, sorry I wasn't clear on that.

It does run on weather curve based on outside sensor just on a lower curve compared to their recommendation for rads.

championc

The meter is GONE !!!

John.G

How does the inside unit, the condenser, "work", where the compressor gives up its heat from a coil in a cylinder, a sort of buffer tank where all the water in it is circulated through the rads or UFH and through the HW cylinder heating coil, what are the flow/return temperatures?, what capacity is this cylinder or buffer tank?.

Is the compressor variable speed?

championc

I have NO buffer tank. The house is all rads. There is no point in heating volumes of water which are not necessary. The heat pump unit has an internal reservoir of a litre or two (the heat exchanger), which is what is heated before being circulated around the rads circuit.

Flow temperatures are dictated by a weather curve setting, which are relative to the outside temperature.

Current flow for our house is mid 30's, but flow is, at the end of the day, whatever is needed to replace the heat being lost.

John.G

What is a typical flow/return dT

Is the ASHP variable speed?

graememk

Just want to add, with monoboc there is no inside unit at all.

I have a ecoforest myself but has very similar design, compressor is inverter driven so is variable. The internal storage in it is just the heat exchanger.

To heat domestic hot water, you just have a 3 way valve that switches from radiators to hot water and also a different temperature profile for that.

championc

https://www.boards.ie/discussion/comment/122819052#Comment_122819052

dT should ideally be around 5 Deg. Fast flow is facilitated by having the right pipe sizing. For instance, you cannot have a 1/2" feed pipe branching out into 4 x 1/2" connected rads. The AroTherm 5kW unit pump runs at 860 l/hr

John.G

Does your unit display the evaporator and condenser pressures and temperatures?

What refrigerant are you using?

zoom_cool

Good night tonight to test @championc

championc

https://www.boards.ie/discussion/comment/122829015#Comment_122829015

It is indeed

Ours is running constantly since about 14:00, hovering around 800w constantly.

But the house feels lovely - the best ever. No feeling of cold spots, but not toasty warm either.

Seems like the compressor is running around 50% of the max speed I have seen (40 RPS).

According to my stats on Econcms (link in the first post), I have a COP of 4.24, electric usage of 9.5kWh and generated heat of 40.3. it will run for another hour. I only run it from 10:00 till 23:00 daily.

If we were still on gas, we wouldn't have the same level of heat throughout the house. We previously only really heated the rooms we used. We would have needed to burn about 6m³ of gas for 60kWh of gas for about 40kWh of heat.

serox_21

How was the heat pump behaving last 2 days considering lower temperature and high outside humidity 94-95%.
Were there many defrost cycles.
I noticed a few small gaps like on/off on your graphs for last 2 days between 12PM-2PM. Are those defrost cycles followed by 1-2 hours of running almost full load(2kw input, 7 kw output power).
What is the max flow temperature set for heating the house. Noticed around 42-43 C for outside temp of 5-10C.

Is it set to reach a temp of 50 or more for lower outside temps?
Looks like it takes a few good hours to reach the 20C temp target temp in the house after being turned off for the night.
It will take up to 4PM(6 hours) to increase the temp from 18C to 20C.
Are you planning to let it run over the night as well?
Maybe for a few days to see how the COP is with a full 24h runtime. Last night 12/13Nov inside temp was low, 16C. Not a comfortable temp for most people.

DC999

https://www.boards.ie/discussion/comment/122829080#Comment_122829080

Beyond jealous! We've 2 small electric rads running at a combined 800w. You're heating your house for our 2 rooms! Hats off for the self install

John.G

To satisfy a room temperature of 20C with a OAT of 5C my rads need to run at 60% output (of their T50 rating) with flow/return temps of ~ 56C/51C. If I ran with a flowtemp of 42C then I would only get 29.4% output so to get a decent COP at 42C would need to upsize the rads by a factor of 2.04.

At a OAT of 0C my rads need to run at 80% output with flow/return temps of ~ 65C/60C so would require a upsizing by a factor of 2.7 to run with flow/return temps of 42C/37C.

I would certainly be looking to upsize the rads by a factor of 2.0 if I ever install a ASHP.

championc

https://www.boards.ie/discussion/comment/122833822#Comment_122833822

There is a max temp setting, but this is a threshold and has no bearing on the flow temperature whatsoever. Flow temperature is totally dictated to by the outdoor temperature sensor. It does in some way work with the indoor temperature if you want.

The gaps between 12 and 2 are purely cycling. I run the house at 19 deg up to 14:00. So the minimum heat delivered is greater than the heat being used.

I have had no defrost cycles yet.

I have no intention of ever running the house 24hrs. We never did before and I don't see why I would suddenly start doing it now. I am downstairs each morning for 20 mins before shooting out the door, so I'm not going to heat the house for that - and never did previously.

The main thing for me was the setting of the weather curve. Set too high and the water heats too hot and leads to more cycling. Loo low and the house won't heat - simple.

I have it set to 0.60. Yes, whether it was 5 deg or 10 deg outside, the rooms still heated up to 21 (the sensoComfort unit reading is a bit out). Yes, from 14:00 it only got up to temp by 19:00 or later, but that was perfect. When rushing around, you don't need the heat as much. That's why from the morning until 14:00 the max is 19 deg. The missus doesn't want it hotter. You also get some solar gain too invariably

championc

https://www.boards.ie/discussion/comment/122834589#Comment_122834589

What you should do is to start and experiment by turning down your boiler temperature. It may surprise you how well the house heats, but of course it won't get up to temperature nearly as quickly.

The one thing that has surprised me is the air changes per hour. They aren't nearly as high as I designed for. Mind you, I never planned to heat the entire house as we never did before, but we now do as it's cost per m² is definitely lower and it reduces the chance of cycling in the mornings

John.G

https://www.boards.ie/discussion/comment/122836007#Comment_122836007

Yes, and because a lot of the winter time is spent between 5C and 10C then I could just boost up the rads in the morning for a hour or so and then reduce the flowtemps again as my heating is on for 16 hours/day. With my existing rads this is the sort of settings I require, if I do install a ASHP I would just install a extra rad in each of 4 downstairs rooms as we only maintain the upstairs at 17C/18C.

Radtemp OAT Radoutput

75C -5C 100%

65C 0C 80%

55C 5C 60%

45C 10C 40%

35C 15C 20%

DC999

https://www.boards.ie/discussion/comment/122836007#Comment_122836007

Did you do anything to reduce air changes pre heatpump?

championc

No. And I saw a YouTube video of Glyn Hudson who said the same thing.

So the best measure is really using your gas boiler as a sort of test / benchmark

Take a daily meter reading of the gas meter for a week. You'll have a rough idea of your boilers' efficiency. So then you have your daily heat requirement - or at least an indication

championc

Some people looking at my data will have seen intermittent heat generation stats from midnight to 9am. This is the pump running to ensure that the water in the system does not freeze with low overnight air temperatures.

The MOST IMPORTANT thing with getting a heat pump installed is getting Live Data. Data is King. Apps are a guide, but you won't see stuff like the pump running but no power (except a few watts) being used

10-10-20

@championc, did you say somewhere that you installed a heat-meter on the new A2W system (or am I dreaming) or did you just integrate it with Econcms with a Raspberry Pi?