help me please F GAS

[Gary Gun]

Can someone explain to me the proccess of replacing a compressor , including all required paperwork under the Gas Regulations ? (im going through my Fgas course and have been given some test questions). Cheers

[wingman]

Can someone explain to me the proccess of replacing a compressor , including all required paperwork under the Gas Regulations ? (im going through my Fgas course and have been given some test questions). Cheers

What type of system are we talking about ? Chiller, split. VRF/V system ?

[Gary Gun]

for a SPLIT please , Its more about the paperwork really , thanks for the reply.

[wingman]

For a split unit, first of all you need to reclaim all the gas.

The easiest way to do so is using the push pull method with your reclaim unit. You weigh the gas and make sure all gas is off the system by going into a slight vacuum. Write down how much you have reclaimed and check with the documentation of a split unit (most of the time also outside of the unit.)
This give you a good idea if the charge was correct.
You can always determine later how much must go on the system.

Then you make sure the mains are off the electrical connections.

Remove the insulation and the carter heater from the compressor. Remove the electrical connections.

Remove the compressor. if the compressor has rotalocks you remove the compressor, and replace it with the new one.

If it's soldered (most of the time) you need to make sure the unit is also disconnected from the pipe work and all valves are open, this is to connect nitrogen to the system when soldering. about 4l/min is more then enough.

Don't forget to change out the filter as well when you replace a compressor. It's important to do that.

once everything is connected again, you pressurize the system as indicated on the id plate of the outdoor unit or I use the refrigerant slide to determine my initial test pressure. As a rule of thumb I take 55°C at the refrigerant that is on the system. With R410a that would be some where around 34 bar.

You check all your fittings and solderings with a bubbling solution. If you find nothing at all leave it on the system for 24h (I know for practical reason you cannot do that most of the time) Most of the time I wait about 1 hour if all is well I remove the nitrogen and connect my vacumpump. I make sure the vacum is below 270pa, the reason for doing that is simple, water evaporates at roomtemperature at this given pressure. leave the pump running, and close the manifold, and pressurize the system again, this time about 0,5 bar and revacum the system.

Once this is done you can charge the system with the refrigerant you have reclaimed.

As for documents, you will need to give your customer a document that you have pressurized the system for a period of time. Indicating the time, the pressure you have put on the system. The companies certification number, your name and certification number.

30 days after the repair you must do a leak test of the system using a leak detector that has a tolerance of atleast 5gr/year. If the system is ok, you need to make a document stating the system is leak free.

On this document, you need to have your name and certification number, your company and it's certification number. The date your digital leakdetecator has been calibrated and how accurate it is, brand (make) and serial number.
You need to indicate if the system was pressurized with gas or if it was running normaly.
you need to indicate if the system is leak free or not.

Then, if you had to charge the system with extra gas, you need to make sure you keep a bookkeeping of your gas bottles. Each bottle has to be accompanied with an identification paper indicating where you bought the gas. What gas it is and how much it contained when you bought it and the serial number of the bottle.

Whenever you have to charge a system you need to make note of that on the paper that is accompanied with the bottle. Every thread on this paper has to include that amount of gas charged/reclaimed, the adres of the installation and the reason why.

I hope there are other people reading this thread and can confirm what I have just said.

[Brian_UK]

I would add a small thing on the safety side.....

When removing a brazed in compressor it is often recommended that you cut the old pipework instead of unbrazing the joints.

This is to prevent the risk of fire due to oil in the pipes.

You might like to add general safety comments such as this and having a fire extinguisher and a fire watch afterwards; making the area safe with barriers. I know it goes on a a bit but think how you would prepare a method statement if the job required it.

[wingman]

Thanks Brian, I totaly forgot the safety aspect.

And ofcourse the fact it is better to cut the pipes instead of unbrazing joints especially when you don't know what gas is on the system. For all you know the fridge you work on used to run on isobutane.

I've seen what isobutane does and I don't intend to see it any time soon.

Unbrasing is possible, but only and only when you have the possebility to use nitrogen as a umm ... anti oxydant ? (is that the correct translation ?)

[Gary Gun]

Thanks svery much people big help , cheers

[John MacK]

30 days after the repair you must do a leak test of the system using a leak detector that has a tolerance of atleast 5gr/year.

The requirement is that a repaired leak is checked again, within 30 days/a month of a repair.
The check can be carried out on the same day as the repair. (if the plant is back in service)
Not read the spec on the leak detector anywhere in legislation.