anyone got split A/C in their home?

[Trevorleach]

I’m interested in fitting some of these. Am I right in thinking it’s just the pipes that need to be drilled through the walls and the inside unit just recycles air in the room (ie no air duct to feed in from outside )?

You will need a vac pump, they are already pre gassed, so fit them, vac them and then open the screw and away you go.

 

[daxliniere]

Mitsubishi make great air-con and MHRV, I've had one of their big MHRV at my studios for ventilation and heat recovery since 2017 and it's been great.

 

[daxliniere]

You will need a vac pump, they are already pre gassed, so fit them, vac them and then open the screw and away you go.

No, the lines also need to be dried with nitrogen and pressure tested for warranty. The refrigerants are highly hydroscopic and moisture in there looks will damage your condenser.

 

[steveo3002]

Mitsubishi used to be well regarded

im only repeating what i read , heavy industrial mitsi no good , mitsi electrical is good , must be 2 seperate brands

 

[JimmyS]

Yes Mitsi electric and industrial are 2 completely different companies. Mitsubishi Electric and Daikin are probably the 2 most popular brands in UK.

 

[daxliniere]

MHI is good.

 

[steveo3002]

any comments on midea , which are relabled mr cool , pioneer , senville as seen on amazon
half the price if i diy it ,,,but then if it breaks after 2 years vs 15 on a mitsu whats the point

 

[Trevorleach]

No, the lines also need to be dried with nitrogen and pressure tested for warranty. The refrigerants are highly hydroscopic and moisture in there looks will damage your condenser.

Well as I fitted my own I am pretty sure the warranty means little, fitted 4 over the last 20 years, one I did not even vac and it is still working.

 

[steveo3002]

the vac machines are only 100 ish on ebay and a member offered to loan his on here , but yeah several reports that not vaccing didnt make any odds

still cheaper to buy the gear than pay some robbin git £1000 for a easy days work, always resell it for half price to make it cheap

 

[Pete.]

MHI is good.

An installer I spoke to said if you want parts or aftersales service go with ME they are far better than MHI.

Anyway, I highly recommend looking at Samsung Windfree, especially if you use a modern Samsung phone coz you can control it from the app and set schedules, monitor power usage etc. The best feature is the wind free feature though I got mine running right now. If I left the blower on all night I'd be dried right out by now. But the wind free just cools the room gently with little to no airflow. A big plus for the bedroom.

 

[DennisCA]

what btu ? any specs on it , was told avoid mitsi industrial

Mitsubishi units have always been one of the most reliable brands in my world. ****ty app though.

e: Oh yeah it's Mitsubishi Electric I was thinking of

 

[JimmyS]

No, the lines also need to be dried with nitrogen and pressure tested for warranty. The refrigerants are highly hydroscopic and moisture in there looks will damage your condenser.

Pre gassed lines cant be dried with OFN. If piped conventionally then could be triple vacuumed by vac pumping and breaking vaccum with OFN but either way its the vaccum that dries the pipework. Which refrigerant is highly hygroscopic? Possibly the oil could be hygroscopic some of the mineral oils used were back when R22 and R502 etc were used. Moisture unlikely to damage condenser can block expansion valve and can degrade refrigerant or oil but never heard of it damaging a condenser.

Only refrigerants I can think of that are hygroscopic off the top of my head are R717 and R718 and lithium bromide which used to be used in absorbtion cycle refrigeration cycles but from memory water was the refrigerant in lithium bromide systems.

 

[knighty]

compressor oils are all very hygroscopic, maybe there's the odd one that isn't... but all the common ones are

vacuuming alone isn't enough to dry out lines, and tbh I'm not quite sure why... maybe the water can freezer under the vacuum? - bit of a guess because I know heating helps when vacuuming lines out

for a normal home sized ac lines a vacuum is enough, you have problem when you're vacuuming moisture out of larger systems and/or full systems not just lines

I pressure tested 3 new systems at work once and my brand new nitrogen bottle ran out before I finished, size W I think? (the big 300bar ones)

 

[Pete.]

My Samsung systems came pre-charged for a certain line length. so the installer told me. The guy had to get a bottle to add a bit for the bedroom unit because it was just over that distance. The living room one was just through the wall so no additional refrigerant required for that.

 

[knighty]

it's surprising how accurate the refrigeration charge has to be / how well a system needs to be balanced

it can be a bit low and all is fine, but then it's a cold day or the charge drops very slightly and suddenly you have bubbles in the liquid line and everything goes to pot

as soon as bubbles hit the expansion valve (in small systems it's not even a valve, just a restriction with a small orifice) it can't meter the flow properly any more, there's surges in th pipe work as the flow speeds up/slows down etc.. knocks everything out of balance

 

[steveo3002]

are the warrantys worth anything , i was reading one the other day 5 year warranty , then thats subject to matey servicing it every year and no doubt adding on some extras , so a few years you could afford to stump up for own spare parts and dust the filters off yourself

guessing diy fit they will say f.o if no f gas papers ?

 

[Pete.]

Mine are service annually at 50 quid each so it doesn't need to be expensive.

 

[steveo3002]

do they just dust it off though or anything techie?

 

[Trevorleach]

are the warrantys worth anything , i was reading one the other day 5 year warranty , then thats subject to matey servicing it every year and no doubt adding on some extras , so a few years you could afford to stump up for own spare parts and dust the filters off yourself

guessing diy fit they will say f.o if no f gas papers ?

I have never done anything to any of mine in years, apart from clean the internal dust filters on the inside machine, in my mind they are like all cheap white goods, use them until they blow then replace them.