Frequently Asked Questions

Buying New Equipment

What is CFM and what is the difference between CFM FAD or displacement CFM?

The amount of air provided by your air compressor is measured in CFM (cubic feet per minute). This measure is the most important element in choosing the right air compressor or when adding tools to your compressed air system – for two reasons.

Firstly, and most obviously, you need to know the total CFM consumption of the equipment that will be supplied by your compressed air system so you can size your compressor correctly.

Secondly, if you are buying a piston (reciprocating) compressor, manufacturers supply two sets of data for CFM. The displacement CFM is the air produced at the pump but the figure you need to rely on is FAD (free air delivered). That’s a measure of the air delivered to the outlet. When buying a piston compressor, make sure to match your consumption against the FAD figure.

Can I add to my compressed air set-up?

That depends on your current consumption. Usually when we size a compressor we suggest a unit slightly larger than the current air tools require. That futureproofs your air compressor to some extent and ensures that you do have some room for expansion without having to replace the compressor.

There is, however, a limit to your expansion capabilities. To find the spare capacity in your compressed air system, add up the current consumption in CFM (cubic feet per minute) then subtract that amount from the CFM generated by your air compressor. Now compare that figure with the required CFM of the any new equipment you wish to add. If the amount required by the new tool is higher than the remaining CFM capacity, you’ll need to explore bringing in a new air compressor with greater capacity.

Bear in mind also that bar pressure affects the amount of CFM produced – the higher the bar required the lower the CFM.

What size Air Compressor do I need?

The best way to determine what size air compressor you need is to add up the consumption of each piece of equipment using air. Ideally collate the information in the same measurement format. We (and the rest of the compressed air industry) predominantly use CFM (cubic feet per minute).

Once you have this information a good ‘rule of thumb’ is to divide the CFM by 4 to calculate the required HP. Then to work out the required kw, take the HP x4 then divide by 3. There are limitations to this calculation though so when ordering an air compressor always give the cfm you need as the higher the bar pressure the lower the cfm the compressor will produce. In many cases this is difficult to ascertain so call one of our experienced engineers for advice on 0114 243 2347.

H&S Info

HSE have just visited; can you help me understand what they need from me?

Yes, we are experts in the legislation surrounding compressed air systems, so if the HSE have asked you to make changes to your compressed air system and you’re not sure what or why, call us on 0114 243 2347. We will immediately action any HSE requirements so your business remains safe and compliant.

Can I have the material safety data sheets for any oil I buy?

Yes, these are available on request.

Can I have a Risk Assessment & Method Statement for any work you carry out?

Yes, we provide RAMS for all works.

Prices & Payment Methods

How can I pay?

We accept various methods of payment. If you request a quotation from us you’ll find the relevant payment terms and methods on it. In all other cases payment is due on order for parts or on completion for callouts.

  • Credit account – download form – (usually takes a few days to set-up.)
  • Credit or debit card in person at our offices (incurs a 2% charge)
  • Cheque
  • FPS or BACS online banking payment to the following details:
    • Bank: Yorkshire Bank plc
    • Bank Acct Name: G,SP,PA Algar & S Kidd T/A Algar Air
    • Sort Code: 050868
    • Acct No: 33271697
    • IBAN: GB86YORK0508683327197
    • BIC:YORKGB21868

Is there a re-stocking fee?

Yes, if you buy a part from us that isn’t faulty most manufacturers charge us 20% re-stocking fee as a guide.

What is the labour rate?

We charge £38.50 per hour (minimum 1 hour and then 15 minute increments thereafter) Discounted Labour rates available for Service Contracts.

Is there a call out fee?

No we do not charge a call out fee. We pride ourselves on providing a quality affordable service and this is part of our commitment to this.

Servicing/Using your Air Compressor

What do I do with waste water?

Compressed air holds a lot of water vapour. Once that vapour becomes cooled into a liquid (condensate) it’s a dirty, oily mixture that can’t simply be poured down the drain. Its disposal is regulated under the 1991 Water Resources Act.

Since the condensate is approximately 95% water and 5% oil, condensate management systems (oil/water separators) should be used to reduce or eliminate the amount of oil in the condensate. Once the water has been through the separator it should then be piped into the foul sewage system.

What weekly checks should I be doing on my compressed air system?

We recommend the following:

  • Drain the air tank/receiver/vessel
  • Check any autodrains are working correctly
  • Check/clean out any external panel filters
  • Check for any air leaks on pipework
  • Check for oil leaks on hoses
  • Check oil level in compressor

If you don’t have the time or resource or time to carry out these checks on your compressed air system, we can do it for you as part of your service schedule or maintenance plan. To talk to us about creating a plan tailored to your business call us on 0114 243 2347.

Why is there a service schedule on my compressor?

Your compressor needs servicing regularly to help prevent downtime. Consider this: if your air compressor wasn’t working what would be the consequences? What would be the cost in lost production? Deadlines missed? Staff on site but unable to work? How much would this cost your business for every hour of non-production?

Keeping a good service schedule involves replacing service items regularly so they are less likely to fail. Additionally, any potential faults can be identified and remedied early, before they have a chance to cause a breakdown.

When can I have a service engineer?

For breakdowns and repairs, as our motto states ‘your pressure is our priority’ so we do everything possible to get an engineer to you asap and there’s always a callout engineer on duty. When you call us for a breakdown repair, we’ll be able to contact the engineer during your call to us and confirm an accurate time scale. To arrange an air compressor repair, call our breakdown team on 0114 243 2347 day or night.

For servicing, we organise the parts for you then contact you to arrange a mutually agreeable time to carry out the work. Often we carry parts in stock; if not, most kits are available to us within 2-3 days.


How do I turn off my compressor correctly?

All compressors are different so check your manual for best practices, however you can always ask one of our air compressor engineers to show you how to switch your compressor on and off while they’re with you to carry out a service.

Important: Don’t regularly stop the compressor using the emergency stop button or the isolator as, over time, this will damage the compressor.

Why does my compressor struggle to start when it’s cold?

There are a couple of reasons that this may be happening. One reason is that compressors generally don’t like cold weather. Cold affects the oil’s viscosity, making it harder for the oil to flow round the machine and lubricate it. If your compressor house gets very cold in the winter we can help by installing a heater to take off the chill. If you are interested in this service contact us now.

Why have I got water in my system?

The compressed air leaving your air compressor is normally around 65°-75°C. It contains a lot of water vapour and once that comes into contact with pipework/air tanks etc it cools rapidly and turns back into a liquid water. To dry the air we would recommend installing a refrigerant dryer and filters to remove the majority of the water from the compressed air.

If you already have a refrigerant dryer and filters but there’s still lots of water in the system, it’s worth checking that the dryer is switched on. Sounds obvious (and it is obvious) but it’s amazing how many callouts we’ve been to where this has been the simple solution.

Otherwise the filters will need checking for blockages and/or the gas in the fridge dryer may be low. To resolve the problem quickly, call our refrigerant engineer on 0114 243 2347.