Keeping your HGV’s air con maintained will save you money in the long run! A lorry air conditioning guide.
We wrote an article about parking/night time air con. We said it should be getting fitted as standard on tramper's trucks. But some of you got in touch and said either you don't have air conditioning at all, or it doesn't work on your truck and the gaffer won't fix it.
Normal air conditioning, where cold air blows out the vents when the engine is running, has been standard in almost all trucks for quite some time. In the Euro 6 era the vast majority of tractor units have it, and many rigids. Curiously, a few tipper operators resisted fitting it to eight-wheelers for a lot longer than you might have expected, but today it's almost impossible to find something that doesn't have air conditioning.
And rightly so. As far as improving the environment for the driver, it should be right up there in the top ten - probably five - most important developments along with the auto box, power steering, disc brakes, cruise control, fridges, sleeper cabs and lane departure warning buzzers. There are two types; manual air con with the snowflake button for COLD or automatic climate control which will strive to keep your cab at a set temperature.
Air conditioning is a strange bit of truck componentry as it's specialised, and requires special equipment to service and diagnose issues with the system. Many main dealers will have machines to re-gas trucks, but beyond that, they can't really deal with faults.
Air con was optional on most trucks during the 90s
If you're an operator of the old-school persuasion let's get one thing straight, we love you and we know you got to experience all the fun times BUT air con is not a luxury or optional item in 2025. Subjecting drivers to 15 hour days in boiling hot cabs will lead to them leaving your company, which if they're in the 'good' category you do not want.
And 'the air con not working' is not the same as not having air con; these modern climate control systems don't provide the fresh air in through the vents in the same manner an old non-air con truck will. The way the air is routed from outside into the cab warms it by the time it comes out the vents even with the display set on LO. It's not the same as the fresh outside air coming in through the vents of a 30 year old truck.
You're supposed to keep the system serviced. That means getting it re-gassed every 12 months (maybe 18). It'd be interesting to see if your R&M contract includes re-gassing of the air con system, because it really should.
If you do your own maintenance, factoring in the air con is worth it in the long run if you're running trucks over three years old. Either by investing in doing it yourself, or getting in a specialist in the same way you get a tyre service company in to go round everything in the yard, just not as often.
This ERF EC11 Olympic has an air con pod
You might get away with 24 months - on a car - but with the amount trucks are used, annually is a good idea. This will save you money in the long run.
Why? Because the amount of gas in the system will gradually reduce over time. It also contains lubricating oil which keeps seals and pipework in good order.
Simply ignoring the air con until it's no longer effective is not good for it, in the same way never changing your engine oil is. Air con gas is cheaper than air con components in the same way oil is cheaper than engines. We will hazard a guess that NOT having a hot, tired and sweaty driver doing his nut because his truck is a green house and then ending up with vehicle downtime because it has to come off the road to get fixed is something that operators would much prefer. 
Air con experts It's worth contacting an independent air con specialist to service the air con on your trucks, they're going to be much cheaper for parts and labour than the main dealer and can come to your premises. It's also wise to get them checked during the colder months when these guys aren't as busy. If you leave it until the hottest day of the year to try and get your air con fixed, there's going to be a big waiting list.
They'll be able to identify potential future issues and prevent leaks, sometimes simply by doing something like cable tying some protection round a pipe or pre-emptively replacing a worn component such as a rusting dryer. You can buy your own air con machines to re-gas your trucks, but at least one of your mechanics is going to need certificated in its use and handling. Well worth having at least one of your team learning about air con if you can get set up to do it in-house.
Besides, then you can charge for the service to third parties. Which gas? Find out which gas your truck uses.
In 2019 R134a was been replaced with a gas called R1234yf which is better for the environment. However, trucks with existing type approval could continue to use R134a, so you may find as an example a Volvo FH or a Scania S500 from 2020 using R134a while other slightly older trucks are using R1234yf. It's illegal to vent air con gas to atmosphere. Cracking open pipes in the workshop to empty the system without recovering the gas is not only against the law, it's a waste of money as the gas that's recovered from systems can be reused.
R1234yf is a lot more expensive than R134a.
5kg of R1234yf is about GBP500. System capacities vary; a Volvo FH on R1234yf has a capacity of 650g. Some trucks use more gas, a Scania S-Series using R134a uses 1450g.
Failure points When the air con stops working, chances are it's because there's a leak, and there's no gas in the system, or a component has failed.
When connected up to the machine and it shows that the system is in fact simply so low on gas it can't operate, you got lucky. If it's full of gas and not working then it could be the compressor, a pressure switch (this can throw up a fault code and be a very easy fix, which can be handy) or simply a fuse or a relay. Compressor clutches can wear out with age, or they can seize which will throw off the drive belt - they're more likely to seize if you don't keep the system maintained - AND the system will need flushed after a compressor seizure to remove contamination.
If you just fit another compressor without having the system flushed it won't last long. There's the condenser (the radiator part) which sits up front and is a common culprit for leaks thanks to its position making it a target for debris, the receiver dryer (that cylinder shaped thing behind the grille that rusts out on some trucks) , leaking O-ring joints, or chafed through pipes, the expansion valve and the evaporator which tends to live up the back of the dash. All models of truck have a common point or two where they're most likely to leak.
Pressure testing - essential Unless the source of the leak is visually obvious such as the rotten dryer or chafed pipe - sometimes leaks can be visible at joints thanks to the fluorescent dye in the oil - the system has to be pressure tested. This is where the air con specialist, or a particularly well equipped dealer comes in, as they will be able to do so by pressurising the system with inert nitrogen gas and then checking for leaks, often using soapy water to identify tell-tale bubbles.
Monitoring a set of pressure gauges for a period of time will show if the system is holding pressure. If it drops, you have a leak. 
Vacuum test A lot of places will simply hook your vehicle up onto their air con machine and set it to vacuum. This takes about 20 minutes and has to be done every time gas is removed from the system, or after a new part has been fitted.
If the system is hooked up to the air con machine on a warm day with the aim of putting gas in, but there's no gas there, only bit of atmospheric pressure in the system, you can bet there's a leak there somewhere but it'll pass the vacuum test. It works on suction so it'll suck a microscopic bit of debris over a pinhole leak and it'll pass the test which will then allow the operative to fill the system with gas. Problem with this is, it's likely that the gas will leak out within 24-48 hours. If there is no gas to recover, you're probably wasting your time and money by skipping the pressure test check and just gassing it up.
The fast-fit tyre places used to do this a lot with a moneyback guarantee, until R1234yf came in and it became way too expensive.
Dairy work is one of the last places you'll see day cabs like this CF 410 from 07. No idea if it had air con it's just kinda neat
Summing up In the long run, maintaining air conditioning really isn't that expensive.
It makes for happier drivers and it can reduce downtime and additional parts costs further down the line. Times have changed. Drivers today may well be 'spoilt' with those big cabs and auto boxes, but they've also got to deal with excruciating levels of traffic in many parts of the country, an avalanche of health and safety regulations, some of which are more vindictive than they are beneficial.
Add in the lack of facilities and parking in parts of the country, truck crime and all manner of places who are never anything more than dismayed, at best indifferent to having to deal with you and your delivery, being able to cool down and stay vaguely comfortable while grinding round the Great British road network, really shouldn't be denied to drivers. If it's broke, fix it, if it's working, make sure it stays that way. Petition
During our internet searching we noted that a petition has been approved and raised to require the installation and maintenance of air conditioning in commercial vehicles. That means that everything should now be A Fitted with air con and B Should be operational by law. So if you're running around with knackered air con, it's an MoT failure and a potential defect.
You can sign it here: Require installation and maintenance of air conditioning in all HGVs and vans - Petitions