Direct/indirect, Vented/unvented Hot Water Cyliders - Help me understand what combinations work.

[LeanTwo]

Yes, no problem and our trip to New England was interesting!  

 

I am trying to create space in the bathroom by moving the cylinder to the loft and then installing a shower.  I have found (at Cylinders2Go) a vented, indirect (a coil connected to our multifuel stove) cylinder with two connections for my Economy7.)  I currently have two F&E tanks in the loft.  One for storing our water supply and one (the smaller of the two) connected to the multifuel stove. My cylinder, at present, is a typical vented direct (immersions) and indirect (coil from the multifuel) system.

 

My loft is 1.38m high at the apex and the cylinder (170L) I have found will fit.

 

Does my new cylinder in the loft have to be lower in its entirity than the two F&E tanks to work?  Or maybe just one of them?  I'm more than a little confused!

[billt]

The water level in the tank that supplies the cylinder needs to be higher than the top of the cylinder, preferably by more than 400mm. You also need to be careful how the vent is arranged with respect to the HW takeoff. I have a similar arrangement with a very low level difference and I get air drawn into the HW outlet because I didn't arrange the vent properly. haven't been able to face rearranging it yet.

[LeanTwo]

Thanks for your reply billt and the heads-up on the vent/HW outlet.  

[Adsibob]

8 hours ago, LeanTwo said:

My loft is 1.38m high at the apex and the cylinder (170L) I have found will fit.

FYI You could always get a horizontal cylinder if you wanted bigger and height was restricted.

[Nickfromwales]

On 09/10/2022 at 20:11, LeanTwo said:

Thanks for pointing that out Peter.  Mine was put in 35 years ago and is definitely plastic!

Are you sure it isn't GRP, and not plastic?

[Nickfromwales]

9 hours ago, LeanTwo said:

Yes, no problem and our trip to New England was interesting!  

 

I am trying to create space in the bathroom by moving the cylinder to the loft and then installing a shower.  I have found (at Cylinders2Go) a vented, indirect (a coil connected to our multifuel stove) cylinder with two connections for my Economy7.)  I currently have two F&E tanks in the loft.  One for storing our water supply and one (the smaller of the two) connected to the multifuel stove. My cylinder, at present, is a typical vented direct (immersions) and indirect (coil from the multifuel) system.

 

My loft is 1.38m high at the apex and the cylinder (170L) I have found will fit.

 

Does my new cylinder in the loft have to be lower in its entirety than the two F&E tanks to work?  Or maybe just one of them?  I'm more than a little confused!

Let me remove the confusion  

Separate the two systems out to simplify things for you, so the solid fuel circuit first;

One ( metal or GRP ) F&E tank fills with water and that floods the pipework / stove / cylinder heating coil. From that body of water you need a vent pipe, which needs to rise up and over the solid fuel F&E. This arrangement needs a minimum 'head', the distance between the bottom of the F&E tank and the highest point of the system ( the top of the cylinder heat coil ) to function safely and reliably. This means having that cylinder coil and the F&E tank plus vent in the attic is a flat out "NO". 

 

The second F&E tank you have propels hot water, and may also provide a balanced cold feed to say bath taps / shower valves, so this needs to be surveyed, identified and addressed in any upgrade proposal before even getting a green light to look at which cylinder suits / goes where / how to pipe it all up.  The water from that F&E tank comes out of your taps, either directly as "tank fed cold" or via the hot water cylinder as "gravity hot".

 

Right now, it doesn't sound like you can do this conversion, if you wish to keep the solid fuel > DHW facility, sorry, unless you can relocate the cylinder that functions with the solid fuel setup, keeping it lower down within the property?