Guide: How to change your Expansion Vessel

Are you having problems with your expansion vessel and have decided to replace it? We have put together a step-by-step guide so that you, as a customer, can feel secure in carrying out your exchange.

ATTENTION! We do not recommend replacing the expansion vessel if it is inside the pump, only when it is external.

All installations are not done in exactly the same way, but to a large extent. There are many manufacturers of expansion vessels, some of the largest are for example: IVT, Canvac, Daikin, Mitsubishi Electric and many more.

Estimated time required for a change: 1-2h

You need this: Thread tape, e.g. loctite tape

Step 1:

Once you've located the expansion vessel, it's a good idea to inspect it before disassembling it. If you haven't already bought a new replacement part, it's a good idea to check the size of the pan, make a note of the brand and the settings. Another tip is to take a photo of the old vessel to be able to refer back to when installing the new one.

It is very important that you ensure that the size of your new expansion tank is correct, (As a general rule it is better to have an expansion tank that is slightly too large than one that is too small as the water expands by about 5-8% when it heated up).

Step 2:

Once you have ensured that you have the correct size of your new expansion vessel, proceed with turning off the circulation pump. Then turn off the valves out on the heating system on the switches (if present).

Step 3:

When this is done, release the excess pressure via the safety valve on the expansion vessel. If water comes out instead of air, there is a hole in the bladder. To facilitate the replacement, the water in the vessel should be drained before disassembly.

Step 4:

When the expansion tank is empty of water, you can start your disassembly by turning the tank counterclockwise. Even though the container is empty, there may still be some dripping water, so it is a good idea to have a towel handy.

Step 5:

Now put the new expansion tank in place and check that it closes tightly, use loctite tape along the thread for more secure closure.

Step 6:

Fill up the pressure and vent the system on the elements, recommended pressure varies depending on the manufacturer, please check the user manual.

Step 7:

Once the new expansion vessel is in place and set to the appropriate pressure, open the valves out on the heating system on the exchangers again (if there are any) and then start the circulation pump.

Now your new expansion vessel is in place, good job!