Anyone run a Megaflow cylinder at 4 bar pressure?

[cushy81]

Yes I know it invalidates the warranty.
And I know the recommended operating pressure is 3 bar.
But on a large unvented system (3 showers, 4 toilets, 4 storey house), if I was to fit a pressure reducing / fluctuations valve with a return / bypass and PVR and set it to 4 bar to match the mains pressure is that safe?
I know cylinders are pressure tested to 15 bar but has anyone actually upped the pressure slightly without blowing their house up??!

Mods note:

To comply with regulations in the UK unvented cylinders of this size can't be altered from the manufacturers specification in this way.

Whilst unlikely the potential damage from a cylinder is similar to a gas explosion therefore we will not allow posts about modifying them on the forum.

Regards

Mod

 

[flameport]

As in the other thread, your problem is not pressure, it's flow.
Pipework undersized, or there are other restrictions in the pipework, valves or other items.

https://www.diynot.com/diy/threads/increasing-operating-pressure-on-an-unvented-cylinder.508852/

 

[picasso]

Not only void the warranty but your home insurance as well.

 

[cushy81]

Yes that's a fair point I hadn't considered. Of it did blow up. How likely is that though?

 

[dilalio]

How likely is that though?

No idea mate, but I can give you tonight's winning lottery numbers if you want!

 

[cushy81]

How likely is that though?

No idea mate, but I can give you tonight's winning lottery numbers if you want!

Who honestly sits on plumbing forums at 8am on a Saturday morning making sarcastic comments? *rolls eyes*

 

[dilalio]

Me

Drinking a nice cuppa, whilst waiting for one of my extremely powerful, high flow rate showers to become free of missus or kids.

Edit: oh! And you apparently

 

[cushy81]

Me

Drinking a nice cuppa, whilst waiting for one of my extremely powerful, high flow rate showers to become free of missus or kids.

I'm crying

 

[bernardgreen]

My solution to having mains pressure showers is a vented cylinder providing copious hot water at low pressure, 6 foot head, to taps.

The shower is fed with mains pressure water that is heated by passing through a coil in the top of the cylinder. A bespoke cylinder but it cost less than an un-vented cylinder.

It should be possible to produce a cylinder for an un-vented system with an extra coil for a supply at a higher pressure than the working pressure of the cylinder

 

[dilalio]

 

[dilalio]

Or is it...