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converting gravity h/w syst to 3 port valve pump syst
Posted: Fri May 21, 2010 8:47 pm
by alistair1
Can you tell me if it is essential to move the system fill pipe to a position between the boiler output and the pump. At the moment the fill pipe is connected to the return from the indirect cylinder to the boiler. Is the positioning of the feed just a water temperature issue? It would save me a lot of work if the feed could be left where it is.
Many thanks. cammy777 :roll:
Posted: Sat May 22, 2010 2:42 pm
by plumbbob
Proper system design starts with the positioning of the expansion pipe. This pipe has two uses. Firstly it is fitted to the highest point on the system which will allow air to escape when the system is filled. It also is a safety device to allow steam a safe exit should the boiler thermostat fail.
Now the filler pipe should connect to the system very near (within a few inches) to where the expansion connects. This is done to prevent over pumping. Fitting it in the wrong place is a very common error on vented systems.
Have a look at this.
http://farm4.static.flickr.com/3276/309 ... 2ac5_m.jpg
Posted: Mon May 24, 2010 8:07 pm
by hamish72
Did mine and left it as was for the old system which of course was wrong but worked perfectly the old system was a back boiler (gas ) but when I went the whole hog and fitted a condensing boiler to the open vent system I had to change the position and fitted a bypass valve
converting gravity h/w syst to 3 port valve syst.
Posted: Mon May 24, 2010 8:41 pm
by alistair1
plumbbob wrote:Proper system design starts with the positioning of the expansion pipe. This pipe has two uses. Firstly it is fitted to the highest point on the system which will allow air to escape when the system is filled. It also is a safety device to allow steam a safe exit should the boiler thermostat fail.
Now the filler pipe should connect to the system very near (within a few inches) to where the expansion connects. This is done to prevent over pumping. Fitting it in the wrong place is a very common error on vented systems.
Have a look at this.
http://www.flickr.com/photos/33215007@N03/3096856838/
Many thanks for your reply. I looks like I am going to have to move the feed as well as the expansion pipes to the same position on the boiler o/p pipe then. Oh well!!
converting gravity h/w syst to 3 port valve syst
Posted: Fri May 28, 2010 12:49 pm
by alistair1
hamish72 wrote:Did mine and left it as was for the old system which of course was wrong but worked perfectly the old system was a back boiler (gas ) but when I went the whole hog and fitted a condensing boiler to the open vent system I had to change the position and fitted a bypass valve
Thanks for your input"hamish72" but I think I'll have to bite the bullet and do it the correct way just in case.
