Change from open vented to system boiler?

[Gasman77]

In simple terms - a system boiler will not make the water get to your taps quicker, or a better flow. An Unvented cylinder will, and the two are totally different and you can have one without the other i.e OV heating with and unvented, or sealed heating system with a gravity cylinder.

Just annoys me when someone proclaims to be something special when they don't know the basics

 

[Servotech]

Can't see how we all missed this little pearl of wisdom....Servotech, can you tell us how going to a system boiler will give you a better flow to your hot taps? I have been grossly overcharging people by installing a unvented cylinder which I thought was essential to achieve this....

Servotech,
Re-read my post Gasman
I was comparing it to a combi - no-one had mentioned going unvented at this point.

Do us and you a favour fella, get your head in the books before you come on here, give daft advice and the boast about being ' a technical grade plumber' what ever that means? of is 'Technical' another way of saying 'clueless'? [/quote]

If you work for a proper firm they pay you the proper rate.
The current JIB rate for a technical plumber is £14.55/hr
Which is what I am!
Jeeese some people!!
Servotech,

 

[Gasman77]

Errr you have lost me again....

 

[DP]

I was comparing it to a combi - no-one had mentioned going unvented at this point.

Also

can you tell us how going to a system boiler will give you a better flow to your hot taps?

It would be education for me, that is what I am here for, to find out how system boiler will give better flow to hot taps.

 

[Gasman77]

Well that makes two of us then......

 

[DP]

Servotech

The current JIB rate for a technical plumber is £14.55/hr
Which is what I am!

For £14.55, I would stay in bed. Knowledge is power. What you are posting leaves room for more knowledge

You have 3 basic type of boilers. These are open vented, system or combination boilers.

Open vented boiler is 'engine' only boiler which needs a pump, controls and expansion facility before it can perform any usefull task. For hot water it needs a cylinder of some sort to give you hot water. Pump is external to the boiler (let the pump be designated brand X60)

System boiler is a package boiler that incorporates pump X60 and expansion facility within the case. IT STILL needs a cylinder to supply hot water to the taps i.e. no cylinder, no hot water to the taps.

COMBI boiler. This has components that system boiler has plus means of heating cold water for direct instantaneous delivery to hot taps. If my name was Pedanticvindictiveman, I would say I can also hook up a cylinder to a combi boiler to give me much better hot water delivery.

You said in your post a system boiler can deliver HW at the taps. I do not understand how it can do that.

 

[Servotech]

Some combi's now incoperate a strorage capacity so that they can deliver hot water to the taps as quick as a system boiler (obviously via a cylinder) can.

The technical rate of £14.55/hr is the top rate of pay for a plumber in the UK (which is set by the JIB) so if your employer is paying you more than this then they are a very generous employer indeed!

Advanced rate for a plumber is £13.11/hr

A qualified plumber is £11.24/hr

Servotech,
(A technical grade plumber at your service)

 

[ajrobb]

I might be confused about boiler types.

• combination boiler - includes pump, expansion and DHW heat exchanger
  4-pipe system boiler - includes pump, expansion and diverter valve and should support different flow temperatures for CH and DHW
  2-pipe system boiler - includes pump and expansion and might not support different flow temperatures
  heat only boiler - need external pump and expansion or header and might not support different flow temperatures

Perhaps top of my wish list is a Veissmann Vitodens 200W 4-pipe system boiler with unvented cylinder and weather compensation. (Lambda sensor eliminates set up and reduced inspection frequency.)

 

[Gasman77]

I might be confused about boiler types.

• combination boiler - includes pump, expansion and DHW heat exchanger
  4-pipe system boiler - includes pump, expansion and diverter valve and should support different flow temperatures for CH and DHW
  2-pipe system boiler - includes pump and expansion and might not support different flow temperatures
  heat only boiler - need external pump and expansion or header and might not support different flow temperatures

Perhaps top of my wish list is a Veissmann Vitodens 200W 4-pipe system boiler with unvented cylinder and weather compensation. (Lambda sensor eliminates set up and reduced inspection frequency.)

A Viessmann 100 heat only can if wired as a w - plan ( hw priority)

 

[ajrobb]

I don't think the Veissmann 100W has a Lambda sensor.

 

[Gasman77]

I never said that it did! And you are right BTW

 

[DP]

In my last post, I said there are 3 basic type of boilers. These are OV, system and combination.

Each type can then have various options. A 4 pipe system boiler is still a system boiler- it is not an open vented or combination boiler. Similarly, a storage combi is still a combination boiler.

If one wanted to split hair, one could say combination boiler can be wall mounted, floor standing, a heat store (which would still be called a boiler in Scotland) or a storage combi. Storage combi can be wall mounted, in two parts or single unit or floor standing. But by this time I am sure sensible guys will start thinking I am being silly. So, there are only three basic type of appliances unless someone can show otherwise.

 

[ajrobb]

So 'open vented' or 'heat only' are the same? I've seen some manufacturers use 'heat only' probably as they can be installed either open vented with a header tank or unvented with an external expansion vessel.

 

[DP]

Open vented can indeed be fitted with an expansion vessel but, big BUT, vessel is installed external to boiler case AND the pump is external too. In a system boiler, both pump and expansion vessel are already fitted inside the boiler case.

 

[DP]

Some combi's now incoperate a strorage capacity so that they can deliver hot water to the taps as quick as a system boiler (obviously via a cylinder) can.

Storage vessel in a combi is usually 60l vessel that indeed addresses poor hot delivery that a normal combi sufferes from. Once the vessel is depleted of stored enery, delivery of hot water is just as poor as if the boiler were a standard combi.

Subject to water mains being up to scratch, hot water delivery is superior to storage combi.