If your system wants a recharge - don't wait!

Post your Cit/Peu/Ren air conditioning queries or advice.

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Zelandeth
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If your system wants a recharge - don't wait!

Post by Zelandeth »

You may or may not be aware that there's currently a drive underway to phase out the use of R134a which most relatively recent air conditioning systems use.

The effect this has had is that it's vastly pushed the wholesale prices for the refrigerant up. This is only going to get worse.

The local garage I've used for stuff like this currently charges a flat £48 (£40+vat) for an air conditioning recharge. They've told me that once the two bottles they've got are used up, that price will double. Given this is due to the actual purchase price of the gas going up, I imagine that's likely to be the same most places.

So if you're considering getting your system checked, it would be worth doing it sooner than later.

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Michel
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Re: If your system wants a recharge - don't wait!

Post by Michel »

This is true. I had the condenser replaced, accumulator seals replaced and the system regassed on the Scenic on Tuesday by a mobile air con repair man. He told me exactly the same.

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EDC5
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Re: If your system wants a recharge - don't wait!

Post by EDC5 »

Ok, I think mine needs a recharge. I can hear a loud hissing when I first engage the A/C but it subsides after a few mins.

Is this normal or a sign it's running low on gas?

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Re: If your system wants a recharge - don't wait!

Post by xantia_v6 »

The situation seems to be complicated. The EU is restricting imports of R134a https://www.coolcaraircon.co.uk/car-air ... he-europe/ , https://ec.europa.eu/clima/policies/f-g ... slation_en but a total ban is not forecast until 2030. The current price increases of R134a seem to be due more to production issues in China, arising from a shortage of one of the manufacturing ingredients (fluorspar). https://www.coolingpost.com/world-news/ ... ces-surge/. Prices are also increasing in unregulated markets outside the EU.

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Zelandeth
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Re: If your system wants a recharge - don't wait!

Post by Zelandeth »

EDC5 wrote:
22 Apr 2018, 18:58
Ok, I think mine needs a recharge. I can hear a loud hissing when I first engage the A/C but it subsides after a few mins.

Is this normal or a sign it's running low on gas?


Hard to say...some systems just do that (the 107 in particular used to give an almighty "whoosh" from behind the dash when the solenoid valve opened)...others can be whisper silent at all times.

I'd say get it checked - once you've got the gauges on it they can see the pressures on both sides of the system when it's working, and it's easy then to see if a recharge is needed. If there's nothing needed I doubt they'd charge you for it. I'd probably stuff a tenner into their hand if it's a garage you use regularly as it's good to keep them sweet.

It's astonishing how good a picture of what's going on in the system just based on watching the pressures that you can get. All because we know the exact temperature the refrigerant boils at at what pressures.

HVAC stuff is something I've found fascinating for years, and I'm lucky to have had the opportunity to help out looking after several systems on a couple of farms, which did nothing aside from increase that interest. I reckon if I'd been about 20 years previous I might have wound up in it - but the red tape around it these days just on the electrical side of things would drive me nuts - and that's before you even get into the F-gas side of things...it would drive me nuts I think.

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EDC5
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Re: If your system wants a recharge - don't wait!

Post by EDC5 »

That's probably a good idea, unfortunately I don't have such a friendly garage but I may get it checked out, glad to hear that such sounds aren't abnormal.

I personally find HVAC fascinating too, I have a set of gauges but not the adapters for R134a.

I've bought a few portable air conditioning units with the intention of breaking them for parts and replacing their evaporators and condensers with water/refrigerant heat exchangers; the aim being to make my own ground source heat pump, but alas I haven't found the time for that just yet.

I've also bought a 4kw Daikin split heat pump system (another random ebay purchase :lol: ). It's currently lying around in the garage waiting for somewhere to go. I performed a pump down when I collected it from the sellers house so all the gas is safely stored.

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Zelandeth
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Re: If your system wants a recharge - don't wait!

Post by Zelandeth »

Daikin stuff is decent, likely whose kit we'll be using when we get out setup installed here.

Looking forward to that - going to be a complicated system by domestic standards, but nothing that we can't work out. Some of the lines are going to have to be annoyingly long given where the condensing unit (or units) will likely need to live.

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Re: If your system wants a recharge - don't wait!

Post by EDC5 »

Sounds interesting, big job then?

As I say, I performed a pump down of this ebay Daikin unit, ( I read a manual for it online before collection as it was still installed in someones conservatory). Is it a case of brazing an accessible schrader valve in the new pipework I run (when I eventually install it), vacuuming the new line and indoor unit for an hour or so, then opening the valves on the condenser unit?

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Zelandeth
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Re: If your system wants a recharge - don't wait!

Post by Zelandeth »

It's a bit of a sprawling house, and the ceiling voids are shallow enough that ceiling cassette units aren't viable anywhere downstairs. It will be a big job, but will make the place far more livable in the summer. Will also be handy come the winter as it will be possible to get heat into just the odd room more easily too. This place is really well insulated, which is both a blessing and a curse!

Setting yours up should indeed be pretty much that simple. So long as the evaporator is matched to the condensing unit and the line set is very roughly the same length it should be good to go. If you're using a different evaporator you'll need to make sure the TXV is correct for your refrigerant etc.

It should be pretty obvious once it's up and running and you've got the gauges on if it's over or under charged. A set of thermocouple probes is handy as well as it makes calculation of the subcooling/superheat a lot easier, and that can often tell you more about the system health (and it's match to the environment) than just the raw high and low pressure readings. Suitable ranges should be printed in the documentation - but from memory it was usually about 12F superheat we looked for assuming "warm but not toasty ambient temperature". Likewise the same number for subcooling. The domestic unit we had there was a Lennox - so everything was in imperial measurements - tied myself in knots with a datasheet that was half metric half imperial once.

What did you pay for it, if you don't mind me asking?

Edit: just found this with a quick Google link here which gives a quick rundown on how to measure superheat and subcooling and what it can tell you.

That's basically a clearer version of my own scribbled notes from years ago.

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EDC5
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Re: If your system wants a recharge - don't wait!

Post by EDC5 »

Thanks for the link, that'll be helpful. Great, that's good to know for when I get round to fitting it somewhere. If I remember correctly it was £80, I don't have the model number to hand but I believe it was a 4 or so kw Daikin inverter with a low wall mount evaporator unit. Bit of a bargain and I couldn't resist haha. I had to uninstall it myself but that wasn't hard really; I left the pipes in their wall.

I also acquired a small bottle of r410a should it need a top up but hopefully I can keep the pipe run the same to avoid having to mess with that.

So is this a multi-split you'll be putting in the house then? That would be ideal.

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Zelandeth
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Re: If your system wants a recharge - don't wait!

Post by Zelandeth »

Sounds like you got a bargain there!

Forgot to add, when you do the install, change the filter drier first too if it's been exposed to atmosphere.

Yep, it will be a multi split, five or six indoor units probably (undecided whether we'll bother with the conservatory, that would probably need another two). Likely to be wall mount units throughout given that the ceiling void between upstairs and downstairs is less than 300mm deep, and that the lofts are mostly floored.

Definitely will make the house more livable in the summer, especially given that two of the bedrooms don't have exterior windows (they open into the conservatory)!

Not kidding myself that this is going to be a cheap, once it's all said and done it'll likely be into five figures (even if I do a fair amount of the work myself), and depending on what condensing unit(s) looks to be best suited it may well be what kicks us into getting the 3ph power connection reinstated...it will be one of those jobs that results in a lot of other things also needing to be done I fear.

The exact configuration still has a lot of question marks on it, which is why I'll be seeking advice from someone who knows more of these art of optimisation of these systems than me.

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EDC5
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Re: If your system wants a recharge - don't wait!

Post by EDC5 »

Thanks, as far as I remember there wasn't a filter drier in the piping to the indoor unit, perhaps it's inside of the the condenser unit ? Either way I will probably install a bidirectional one just in case.

Oh wow, sounds like a huge project. I assume all of the split evaporates are piped separately back to the condenser? Therefore the biggest problem is the piping of the copper tubes.
One thing, can you simultaneously cool one room and heat another with a multi split?

I've seen a few used multi split systems on eBay but for a house you probably wouldn't want any ex-shop equipment as it would probably need replacing.
I'd love to have climate control in each room, it's such a good idea. :-D

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Zelandeth
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Re: If your system wants a recharge - don't wait!

Post by Zelandeth »

It's quite possible that the drier is in the condensing unit in the liquid line right by the compressor. It's a bit easier if it's on the evaporator side as you can change it without having to vac down the whole system - though that's probably less of a common occurrence on domestic kit than on the big semi-hermetic compressor based stuff on the farm that over done the most work on.

As far as I'm aware regarding heating/cooling, it's essentially the case that each condensing unit can either be in heating or cooling mode, so for the most flexibility we'd have to be clever about which rooms were on which units. It's also possible that it may actually be easier to have a smaller unit coupled to each room individually...hence why I really need to speak to somebody who knows this stuff inside out...

All I know for certain is that I won't be getting a system from either Lennox (that thing took years off my life) or Carrier. Mitsubishi or Daikin are the main contenders.

There's going to be a lot of piping involved, especially given the layout of this place.

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EDC5
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Re: If your system wants a recharge - don't wait!

Post by EDC5 »

I'll have to investigate whats in my unit when I next have a chance. Yeah, I'm sure some advice from a pro would go a long way, especially as a multi split is a pretty advanced system to install.

When it comes to piping, what tools do you need? I assume a set of pipe benders and a flaring tool at a minimum. Might be a stupid question but I'm guessing plumbers solder is no good on the joints that need soldering and brazing is the way to go. That being the case I'll probably have to get a MAPP and Oxygen blowtorch?

Image

Here is a pic of the same type of condenser unit I have (I think its a Daikin RX35JV), however instead of the high wall mount evaporator I've got the low wall mount one (about the same size as a radiator).

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Re: If your system wants a recharge - don't wait!

Post by Gibbo2286 »

Had a chat with my garage mate today about the air-con gas pricing, he tells me that last year he was paying £60 a bottle for the stuff, this year same stuff £340 a bottle.