Does Open Vented Heating System need Expansion Vessel?

bonizilla

Hello Masters of Plumbing&Heating, I need some advise here.

I have a boiler + Hot Storage in my heating system, it is an open vented system, I can observe that because there is a pipe coming from the hot press to my cold storage, when hot water expand it goes up to cold storage and pouring there.

I have a small pantry downstairs in my house that I need make some space and there is this red expansion vessel connected to the pipes that I want to take off from there.

My question is: Can I get rid of this vessel without compromise anything in my heating system, since my system is an open vented?

Regards

Everton

10-10-20

Hi! Are you actively seeing water pouring from the expansion pipe into the cold water tank, or are you just describing it's function?

bonizilla

https://www.boards.ie/discussion/comment/122421416#Comment_122421416

Hi, I don't see it properly becouse it is placed in the attic, but I feel the expansion pipe gets hot way up. I think the hot press is divided in 2 parts, correct if I'm wrong, 1 part is the hot water that goes to taps, and the 2 part is the water that goes to radiator heating system. The red expansion vessel is connected to radiator system.

Lenar3556

Your domestic hot water system seems to be open vented. But you may have a sealed central heating circuit which the expansion vessel is for.

10-10-20

So no, you can't remove the expansion vessel, it would compromise the central heating system.

John.G

What colour is the expansion vessel and what type of boiler, oil/gas, make/model?

bonizilla

https://www.boards.ie/discussion/comment/122423291#Comment_122423291

Hi, the colour is red and my gas boiler is Intergas. I think the the heating system is sealed. So, if I cannot remove it, is it possible to move it to another point of the system? My boiler is placed in my attic, can I move the expansion vessel to there?

Tks

Everton

John.G

https://www.boards.ie/discussion/comment/122424719#Comment_122424719

Should be OK, the gas boiler should have its own internal EV (expansion vessel), a external one is then only required if there is a large numer of rads of if the internal EV had failed. You might try and identify which pipe the EV is connected to, ie, the boiler flow or return, the repositioned EV should then be connected to the same pipe, its normally to the return. There should be a drop down panel under the boiler, try and get the exact model number which should be labeled somwhere in there.

bonizilla

https://www.boards.ie/discussion/comment/122425631#Comment_122425631

Thanks John, I will check it. I have 8 radiators only, but if some issue come up, I will put a new one near to the boiler.

bonizilla

https://www.boards.ie/discussion/comment/122425631#Comment_122425631

Hey John, I have checked my boiler and it is a Intergas Rapid 18 SB with internal expansion vessel, but I don't know if this internal EV is enough for the system of 8 radiators.

John.G

It says in the MIs that I have downloaded……."The appliance can be installed with a wall
mounting jig which houses the expansion vessel (8Ltr). The appliance can also be
installed using the external robo kit 8Ltr or 12Ltr. (Both items are sold separately and
are not inside the boiler packaging)".

The wallmounting jig is behind the boiler so you might be able to see it from underneath the boiler. If the external EV was installed at the same time as the boiler theexternal EV must be retainedn more than likely that the mounting jig was not installed which means the existing EV must be retained, a 8L is quite sufficient for 8 rads.

I will post a photo of the mounting jig in a few minutes.

John.G

Here is the mounting jig with the EV, you should be able to see that flexible hose.

Here is another view, it appears to be 95mm deep so you should see where the boiler is mounted to it if you look at the side of the boiler?.

bonizilla

https://www.boards.ie/discussion/comment/122429448#Comment_122429448

Ah, Okay! I will have a look into it. When they installed this boiler, the expansion vesse was there already, more than 17 years.