Anyone heard or have knowledge of a 3 pipe system?

[Marty32]

Morning all

I'm doing the C&G 6129 and part of my studies (very vague) touches upon central heating now having 3 pipe system? I thought there was was only the 'one' and 'two' type variation, only?
If so, is this only for new build properties as I've searched this forum and there is nowt on this subject?

Many thanks

Mart

 

[chris watkins]

not heard of a 3 pipe heating, unless some one is confusing a revers return system which at some points may appear to have 3 otherwise there are 3 pipe VRV systems that can supply heating & cooling from heat pumps but this is normally air con & not covered in the 6129.

 

[JAP&H]

Beleive Christ W to be right.

Lots of two pipe reversed return systems around here, don't know why but very common to be referred to as a three pipe system.

Also covered in Treloar.

 

[chris watkins]

not so many down here but went to Viessmann Telford offices & thats what they have. oh I am sad!!!

 

[Marty32]

Hi chaps

Reverse system sounds right its just that they say it uses 3 pipes - is there anywhere that I maybe able to read up on this system?

Apologies - not sure what Treloar is?

 

[JAP&H]

Hi Marty, try this link for pic and simple explanation.

http://www.expressradiant.ca/pdfs/app_2pipe_reversereturn.pdf

R.D. Treloar - Plumbing, Heating & Gas Installations.

Tatty old reference I keep in van for those 'senior moments'

 

[Marty32]

Great - many thanks for the info!

Mart

Hi Marty, try this link for pic and simple explanation.

http://www.expressradiant.ca/pdfs/app_2pipe_reversereturn.pdf

R.D. Treloar - Plumbing, Heating & Gas Installations.

Tatty old reference I keep in van for those 'senior moments'

 

[SimonJohns]

3 pipe

Usually gravity hot water pumped ch

Boiler has to be compatible with this type of setup

First tapping. >28mm to cylinder. In gravity setup (flow)
Second tapping >22mm to heating, pumped. (flow)
Third tapping same size as flow to cylinder. This is a COMMAN return connection. And usually incorporates an injector tee to aid circulation

Btw what ever mug thinks a reverse return system is a 3 pipe is mad, how can it be called that. There's only 2 pipes! Flow and return. And yes I know there is 4 pipes in the system I have described. But it is referred to as a 3 pipe. A 4 pipe utilises 4 tappings on the boiler

 

[Bernie2]

Bit like two pipe system but flow and returns are of equal length so improves balancing as the frictional head resistance is the same in both pipes. Its usually called a two pipe reverse return system. Its expensive and uses quite a bit of pipe. They mostly seem to promote it for the ease of balancing.

 

[SimonJohns]

Reference : http://manuals.arated.com/index.php?d=Boilers/Baxi&f=BAXI BERMUDA 45-4 E GCNo.44-077-73.pdf

Page 8

This is an example of a 3 pipe system and what I was attempting to describe

 

[Noxer]

3 pipe system on communial, Flow, return and common return...

 

[Bernie2]

That is a boiler with 3 tapping's one for gravity hot water primaries, one for pumped heating and one common return for them both. The Primary gravity return joining the heating return through a tee or injector tee. It may be of interest to you to look up the "three tee rule" as the arrangement and sequence of tees can be quite complicated and cause many problems. If your looking it up for an exam they probably want to know, if you know the complications and "the three tee" rule. Also why would you use an injector tee instead of an ordinary tee?

 

[SimonJohns]

An injector tee creates a Venturi effect to increase flow on gravity side.

A standard tee installed correctly will have no effect on gravity side

 

[buckley plumb]

Morning all

I'm doing the C&G 6129 and part of my studies (very vague) touches upon central heating now having 3 pipe system? I thought there was was only the 'one' and 'two' type variation, only?
If so, is this only for new build properties as I've searched this forum and there is nowt on this subject?

Many thanks

Mart

is the info you been given what you ment or did you mean a 3 pipe system with 2 zones ? when i went on the biasi course they mentioned doing 2 htg zones with a common return and they said it was ok - dont do it you will get rev circulation - their set up was equaly balanced all pipes being the same length.

ant