Vented or unvented?

[MopeyGecko]

Hi,

I had a plumber around today to carry out an initial survey to see what would be required to upgrade my heating requirements and just wanted to check a few things over with you guys if you don't mind.

Firstly I have linked to a diagram of the current system as it stands now.

The objective is to have a central heating system installed. In my mind before the plumber came out I was expecting to be able to replace the solid fuel boiler with a gas one and add the central heating radiators to this keeping the rest of the system as is and away we go! Now for the outcome of our discussion....

Firstly apparantly I cannot use the existing chimney that the solid fuel boiler is using and would have to run a new flue out of the side wall (house is a listed building so I am reluctant to do this even if it is allowed)

Secondly he was leaning towards an unvented system getting rid of the cistern in the loft but adding a storage cylinder in the kitchen below the boiler with a pressure vessel? thought I understood at the time but I'm confused as to why this is necessary now and whether it is just creating unneccessary work.

Third he mentioned that because the pipe run from this new storage cylinder to the bathroom was quite long he would recommend adding a return pipe to keep the circulation right up until the point of use. (this I understand but surely if the existing storage cylinder/immersion heater is in the bathroom in any case and the boiler is sat right next to the kitchen sink this is a non issue correct? (only an issue if he's introducing this storage cylinder below the boiler in the kitchen)

Lastly there is a 2nd WC and washroom some distance from the tank in the bathroom which currently goes up into the loft, along to the corner of the building and then down to the ground floor. He mentioned removing this pipe and taking it a shorter route along the first floor and then down and back again. I think this makes sense with the current system but with his new proposed system surely it would be better running along the ground floor direct to the room in question?[/list][/list]

 

[htgeng]

You can't go unvented with solid fuel or aga (someone correct me if wrong on aga).

Do you have access to natural gas?

 

[MopeyGecko]

Thanks for the reply

yes the Aga is currently running from natural gas. So basically what you are saying is my hunch was correct and simply replacing the solid fuel boiler would be the best option? Could I still add a return flow to the longer pipe runs back to the storage cylinder in order to avoid the delay waiting for hot water? This would definately simplify the installation as the only real work is adding the radiators.

 

[gas4you]

Although they do not have the best reputation, mainly due to the idiots fitting them I think, Halstead make a special flue liner for their condensing boilers that fits up an existing chimney, it is an expensive option though, but cures the problem you have.

Unvented is the most expensive option to go for, although IF you have at least 3 bar cold mains pressure and at least 20 l/min flow rate and at least a 22mm cold mains to it, it is the best performing option and you would not need shower pumps etc.

If on the other hand you are happy with your hot water delivery, why change it?

I would recommend replacing your old hw cylinder though for a more efficient fast recovery cylinder. This would compliment your new efficient condensing boiler.

It's your money, you have what you want. I always give my customers all the options, benefits and drawbacks of each and let them decide.

I often give a quote for each system type as well. I only want to fit what my customer wants at the end of the day, not what I have pushed onto them, even if I know my recomendation would be better

 

[MopeyGecko]

I often give a quote for each system type as well. I only want to fit what my customer wants at the end of the day, not what I have pushed onto them, even if I know my recomendation would be better

I'm pretty open to suggestions to improve the system so long as it doesn't inflate the price significantly for a small improvement. Some of the hot water runs are quite lengthy so it would be nice to have faster running hot.

Seriously, stay away from the chimney idea. Arfurrr is correct about the kits for them, but as stated, they`d be difficult to secure. A vertical (spelt correctly this time) flue is the least expensive and easier option.

Found this in another post, I definately like the idea of a chimney flue and in fact i believe the aga is vented like this in any case with a flexible flue up the chimney. Why do people seem to shy away from this option. I'd rather not bash a hole through a 200 year old wall and have it come out right next to my front door if it can be avoided.

 

[gas4you]

The Halstead is a plastic type liner.

I would recommend having the chimney well swept first though.

It is fixed top and bottom and a spacer device fitted along it occasionally inside the chimney.

Having installed many boilers in listed buildings, I doubt very much you would be allowed a flue in that position anyway.

 

[D_Hailsham]

As it is a listed building, I would find out what you are allowed to do before going any further. The powers could well have something to say about location of boiler and the type of radiators you install.

 

[Paul Barker]

I am nowadays very much against unvented because the money grabbers have decided the lifetime qualification I hold suddenly lasts 5 years.

I shant retrain

Anyway most unvented jobs are going round fixing multitudinous problems left by the untrained, who don't have to retrain.

I'm sick of telling customers how much is wrong with their blessed unvented installations. It'll be great turning it down.

We have an open vented hot water system properly designed which flows water to the taps perfectly acceptably, and should I want a powerful shower I would fit a trevis boost.