Unvented Cylinder Vs Tradiotnal Vented - Did I Do This All Wrong?

[JackK]

I have a four bed house with two showers - Over the last two months I have replaced the coffin tank in the loft, the vented indirect cylinder and now installed a Stuart Tunrer Monsoon 3.0 Bar Pump.

The costs so far has been:

Coffin Tank £250
Cylinder - £350
Pump - £650

I have to say that I am not that happy and think I made a huge mistake - I should have had an unvented megaflo like system installed and got rid of all of this - It would have saved space and been cheaper and pressure would have been better and would have been more fancy. The pump is also noisy when it operates

My partner wants to remove it and have a MegaFlow installed

Did I make a mistake by keeping it simple and using a vented cylinder? What are the advantages of a vented cylinder and why would anyone buy one if they have good mains pressure

 

[bernardgreen]

What are the advantages of a vented cylinder

They do not require essential safety devices such as pressure relief valves. Safety devices which have to be tested on a regular basis,

 

[JackK]

They do not require essential safety devices such as pressure relief valves. Safety devices which have to be tested on a regular basis,

Like a gas safety check - I cannot imagine that a £50 annual safety check would be a reason to avoid a far superior system

 

[Madrab]

What are the advantages of a vented cylinder and why would anyone buy one if they have good mains pressure

> Functions at atmospheric pressure, so Inherently safer
> Can be installed and maintained by a competent person without specialist quals
> Very little maintenance required
> Simplicity
> When installed correctly with the correct pipework/outlets, can perform perfectly well

 

[bernardgreen]

I cannot imagine that a £50 annual safety check would be a reason to avoid a far superior system

£50 not a problem if the safety check can predict a failure that occurs after the annual safety check.

why is an unvented system better ( far superior ? ) than a vented system ?

 

[Johntheo5]

I have a four bed house with two showers - Over the last two months I have replaced the coffin tank in the loft, the vented indirect cylinder and now installed a Stuart Tunrer Monsoon 3.0 Bar Pump.

I have to say that I am not that happy and think I made a huge mistake - I should have had an unvented megaflo like system installed and got rid of all of this - It would have saved space and been cheaper and pressure would have been better and would have been more fancy. The pump is also noisy when it operates

The 3 bar pump should still give 2.2bar with two showers in service at say a total flow of 30LPM or 15LPM per end, you will need a fairly good mains suppy to provide all this 30LPM at the same head, you could install a 4bar pump if you require a head of 3.0 bar if this head is required to give you that flowrate.

 

[stem]

I am responsible for arranging maintenance at my place of work where we have an unvented cylinder which has been very problematic and as I don't have a G3 ticket, I have to get someone in who does to maintain it. As well as the annual service cost, in just a few years, the expansion vessel membrane split, and a new vessel was required, and the pressure relief valves failed. On one occasion resulting in the continual running of hot water down the drain continually for several weeks, before anyone noticed. We were alerted that something was wrong by a particularly nasty electric bill. After 10 years the cylinder started leaking and had to be replaced.

At home I installed a vented cylinder with a shower pump 25 years ago and apart from changing the pump a few years back, and the washers in the header tank ballcock twice, that's all that's been required. All jobs that I could do myself and only took minutes not hours. So, I have no desire to change it.

Our pump is audible, but not an issue for us, although ours has a much lower capacity than yours. I'm not an expert in the sizing / specifications, but I don't think you would get anywhere near your pumps performance from an unvented cylinder which is dependant on the capacity of the cold mains supply which is shared with the rest of the street and your property including loo flushing etc., whereas you have a bulk store of water just for the hot water supply all charged up and ready to go.

 

[ianmcd]

unvented cylinder ever time for me, but definately not a Megaflow, get something decent

 

[Harry Bloomfield]

Our pump is audible, but not an issue for us, although ours has a much lower capacity than yours. I'm not an expert in the sizing / specifications, but I don't think you would get anywhere near your pumps performance from an unvented cylinder which is dependant on the capacity of the cold mains supply which is shared with the rest of the street and your property including loo flushing etc., whereas you have a bulk store of water just for the hot water supply all charged up and ready to go.

Noises are a great diagnostic aid, for knowing things are working perfectly normally. My home is full of quiet noises, that I mostly do not notice, unless something is amiss. If I listen out for them, I can just about hear the boiler run, the loft tank refill after hw has been used, the water meter tick, the fridge or freezer start up, noises from birds outside, when a window has been left open, the hum of the bathroom fan. Even the floor boards have their own noises, when someone or the dog steps on them, from which I can work out where they are.

I would miss those small noises, they tell me everything is working as it should.

 

[Mottie]

why is an unvented system better ( far superior ? ) than a vented system ?

Mains pressure hot water, no noise of the cold water storage tank filling up, in fact, no cold water storage tank at all in the loft to freeze/leak/overflow are the reason’s I changed from a vented system. It’s given me more space in the loft to store more shît too!

 

[Harry Bloomfield]

Mains pressure hot water, no noise of the cold water storage tank filling up

Which is a downside, when it comes to filling a bath. With a vented system, I can run both hot and cold at full flow, at the same time. An unvented system has to share what ever the water mains flow rate is, between the two outlets.

 

[Mottie]

Which is a downside, when it comes to filling a bath. With a vented system, I can run both hot and cold at full flow, at the same time. An unvented system has to share what ever the water mains flow rate is, between the two outlets.

I’m not in that much of a rush to fill a bath Harry. Are you? If speed of bathing is a concern for people, perhaps they should try taking a shower.

 

[bernardgreen]

I find the subtle sound of water dripping into the cold water storage can be useful as it warns me that a tap may not be fully turned of.
It is handy having that water storage for when the water supply fails.
Filling toilet cisterns from low pressure supply means they fill silently an the washers in the valves last much longer, Same for taps and the valves in the washing machine.
I do have the luxury of a mains pressure shower by using a shower coil in the top of the vented hot water cylinder.

 

[JackK]

When did your water supply last fail - I live in London and never happened to me

I really think unvented is the way to go - I spent more on a vented system then an unvented cylinder - Silly me

Also maintenance is actually easier - You only have one tank that can go wrong not a pump, cylinder, cold water storage

Can you imagine of 200 litres of cold water came through your ceiling with a vented setup? Who says unvented is more dangerous ?

 

[Johntheo5]

You surely considered the unvented route so why did you opt for the vented system then? and what is the problem with the system?.