r290 mini split/A2A

[HughF]

I just finished installing this last night, at my off-grid place in Dorset. This is to provide shoulder season heating (and possibly all winter heating) in a room that currently has a burnt-out woodburner as the only source of heat. We don't have any central heating at this property. The woodburner will be in the metal skip soon.

 

Easy install, and so far seems to heat and cool well. 700w when in heating mode.

 

 

[HughF]

In case you were wondering, yes, this came from appliances direct. It was about £550 or something.

 

I didn't use the supplied extension set, I simply re-flared the ends of the indoor unit pipework. Pressure tested it to 100psi with pure argon (I'm a welder, I have it in stock) then vacuumed down for 20 mins. Float the low-side gauge up to 20psi then remove the pump+adapter from the service port. Then crack the valves and back seat them.

 

Easy when you watch enough youtube.

Edited June 21, 2023 by HughF

[HughF]

Back in stock at appliances direct, in case anyone wants one...

[HughF]

These things are amazing….

 

 

[RobLe]

How is this unit one year on?  Does it cope ok with heating during cold weather ?

 

[S2D2]

3 hours ago, RobLe said:

How is this unit one year on?  Does it cope ok with heating during cold weather ?

 

I've had mine nearly two years, copes absolutely fine in cold weather. A segment on the display went and appliances direct were very awkward about the "labour" component of the warranty as technically it needs servicing annually by an fgas engineer (despite not being fgas). They still sent out the part though.

[kevinm]

Are you sure it's R290 (Propane)?

 

I was not aware that R290 split systems existed. 

[S2D2]

1 hour ago, kevinm said:

Are you sure it's R290 (Propane)?

 

I was not aware that R290 split systems existed. 

Yes, it's definitely R290.

[HughF]

It’s ‘okay’ at heating - it really struggles to heat my room in this cold snap, but that’s because I don’t have much in the way of insulation or air tightness. In a proper house (this is basically a shack) it would be fine. Defrosts a couple of times an hour, uses about 800-1000w most of the time and puts out warm air.

 

My a2w in Somerset is a far superior bit of kit, but it should be for the price. 

[HughF]

Frosted up this much after running for about half an hour this morning.

[HughF]

Time for another one to heat the upstairs….

[HughF]

Darn it, pressure tested it, pulled it down to 500 microns, went to float the low side gauge to 20 psi (like I always do with these, fitted a few now) and the damn thing ain’t got no gas in it 😂

[JohnMo]

Not a good start

[HughF]

That was a mistaken assumption on my part. Turns out there was gas in it, I just couldn’t get anything on the gauges till I powered it up. Not uncommon according to r/hvac

 

Working perfectly, although a little noisy being bolted to wall of the house. I’ll extend the lines and drop it down onto the ground.

[ReedRichards]

I'm wondering about getting one of these units myself but don't I strictly need an F-Gas certified installer to put it in?

[JohnMo]

48 minutes ago, ReedRichards said:

don't I strictly need an F-Gas certified installer to put it in

R290 is propane, so isn't an F gas. So really comes under the same legislation as a camping stove, soldering torch for copper pipes, barbeque or patio heater.

[Dillsue]

Aren't the regs for fixed gas installs in houses different than those for connecting up a camping stove???

[JohnMo]

17 minutes ago, Dillsue said:

Aren't the regs for fixed gas installs in houses different than those for connecting up a camping stove???

Point was more they are not F gas. So a heat pump (A2A) with propane isn't an F gas appliance 

[S2D2]

12 hours ago, HughF said:

That was a mistaken assumption on my part. Turns out there was gas in it, I just couldn’t get anything on the gauges till I powered it up. Not uncommon according to r/hvac

 

Working perfectly, although a little noisy being bolted to wall of the house. I’ll extend the lines and drop it down onto the ground.

In hindsight I would have fitted mine on the ground, there is a slight noise transfer through the wall after a few years. It's only used for aircon now though so not worth bothering changing it.

[S2D2]

6 hours ago, Dillsue said:

Aren't the regs for fixed gas installs in houses different than those for connecting up a camping stove???

The hard manufacturer restriction when I fitted mine was no joints within the property, if not it could be DIY installed.

[ReedRichards]

I had been looking at what was on offer on the Appliances Direct website.  The units there seem to be predominantly R32s, I had not realised that there were a few R290 units as well.  Hence my question about F-Gas certification.

[HughF]

20 hours ago, ReedRichards said:

I'm wondering about getting one of these units myself but don't I strictly need an F-Gas certified installer to put it in?

If you tell appliances direct that you’ll be using a local installer when you order it, you can put in an f-gas filled one too. Your choice.

[HughF]

18 hours ago, Dillsue said:

Aren't the regs for fixed gas installs in houses different than those for connecting up a camping stove???

These don’t fall under the gas-safe regs either, despite what the gas-safe bods will tell you.

 

Fill volume is something like 600grams of r290, that’s less than a camping stove cylinder.

 

The r290 regs call for no flare fittings inside the property, hence why the line set off the back of the indoor head is 2m long. I don’t flare anyway, they always leak. Expand and braze with a purge flowing.

[ProDave]

59 minutes ago, HughF said:

 

The r290 regs call for no flare fittings inside the property, hence why the line set off the back of the indoor head is 2m long. I don’t flare anyway, they always leak. Expand and braze with a purge flowing.

Dumb question but surely these are copper pipes of a standard size, so can they not be joined with standard solder pipe fittings?  Or does the pressure go too high when running?

[HughF]

On 06/05/2025 at 04:30, ProDave said:

Dumb question but surely these are copper pipes of a standard size, so can they not be joined with standard solder pipe fittings?  Or does the pressure go too high when running?

The hvac world uses imperial sized pipe. And you need to use self fluxing copper phosphorus brazing rods. R290 runs around 400psi. I pressure test to 400 with inert gas then vac down.

 

Linesets can be sourced from AliExpress/amazon/teemu as this stuff is globally standard.

Edited Wednesday at 11:26 by HughF