Why pressurise a system?

[maskell01]

Good evening all.
Recently i have had an unvented cylinder put on my oil fed stantly superstar 80000.
The pressure on the hot water is fantastic,sandblasting in comparrison.

The chap that fitted it mentioned it would be a good idea to pressurise the central heating system too.
(mentioned an expantion vellel and other bits)


The question being, why would he want to do this???
What advantages would this create???



Cheers


Aaron

 

[Ray Stafford]

The question being, why would he want to do this???
What advantages would this create???

Aaron

Hi Aaron.

The biggest advantage is probably the "dry roof". At the moment, you have a fill & expansion tank in the loft, which would disappear if you went pressurised. Getting the water out of the loft reduces a whole range of potential problems, the worst of which is a major leak/failure of the tank.

There are other advantages - sealed and pressurised systems don't corrode nearly as quickly as open vented ones, since no fresh oxygen can be introduced. Also, on an open vented system, minor leaks can go unnoticed for years, whereas a sealed system would high-light even a small leak very quickly, as the pressure would drop.

On the downside, pressurising old pipework can find weak joints that have survived 30 years of low pressure, but leak the moment you jack the pressure up. If this happens in an inaccessible location, you may regret the choice.

My gut call would be to consider the change only if you were having other work done anyway, or if you needed the space in the loft.

 

[maskell01]

That was something i forgot to mention, we are in the middle of moving the stanley across the house as we are moving the kitchen.
The house has had a full replumb in the last couple of years but like you said be weary of soft joints.

Thank you for the reply.

 

[SimonG]

Need to check with manufacturer that your boiler is suitable for conversion to a sealed system.

 

[JCSPLUMBING]

I would always advise a sealed central heating system. That way I haven't got to climb into your loft to tie up your ballvalve

 

[Ermintrude]

Sealed is the future

 

[Best]

Sealed gets my vote also, if boiler suitable for sealing and system well put together.
Advantages are, Dry attic (no heating f&e tank), No air absorbing as sealed to atmosphere, so rads won't fill with air at times, Less corrosion, No risk of massive flooding if, say a pipe was nailed through (no tank to keep letting water into system), Higher pressure system works better and also sealed systems are easier to work on & replace valves etc.

 

[verdigrey]

One of the main reasons is that water under pressure heats up quicker and therefore uses less fuel ,

 

[kris]

It's not uncommon for people to worry about large tanks in the attic and the possible damage it can do , a sealed system does away with that as well as if you had a leak and your house was empty then it's amazing the amount of water that leaks from the system purely because of the lack of gravitational pull on the water, also the water can be a lot cleaner than tanks in attic as seen soon welpers, plus if you have a leak in a sealed system then you know about it with witnessing the gauge dropping , the air in the system is easier to expell under pressure as well as no air can be sucked into a sealed system so there's many advantages to sealed systems

 

[lame plumber]

sealed system wont corrode as quickly and clog up like an open one if it is installed correctly.

 

[maskell01]

Sorry Just got back off holiday. Thank you all for the replys.
its all made a lot more sense. efficency and less corrosion are very appealing.
not not mention the removal of the f&e tank!


Thanks Again


Aaron