Pump position

[Snuky]

Hello,
About one year ago I finsihed a two year evening course in plumbing, since then I have not managed to find any work so I am now starting to forget the basics.

The background
I have just moved house and the heting system needed a little work. The vent and feed pipe for the CH are the same pipe, They link into the system on the boiler flow pipe just after the pump. I have a Rad that is allways turned on to act as some sort of bypass. To get rid of this insanly warm room I thought I would change the vent and feed pipes to how they should be.

The question
At what point should the pump be placed in an open vented system.
Currently my pump is just after my boiler on the boiler flow pipe. The pipe work then runs into the cupboard with the hotwater cylinder, just before the 3 way valve there is two Tees the first goes to the always on rad the second goes to the F+E tank in the loft. THis pipe tees in the loft one to the feed and one to the expansion. Have I got to bring both pipes to a point before the pump?

 

[Rodreguez]

should be from flow from boiler, open vent, then feed, then into pump, then off to motorised valves etc

 

[Snuky]

Thank you, thats what I thought but need to certain before I started.

 

[Rodreguez]

i believe open vent and cold feed should be no more than 150mm apart. also increasing pipe size to 28mm between the vent and feed (if flow is 22mm) will help remove aeration.

 

[ferret]

you have combined feed and vent leave them as they are but move to the suction side of the pump , the rad is off the primary which i assume goes to the bathroom rad which is normal as it gives you somewhere to dry the towels all year , if it gets too hot fit a trv to it , if you have a 3 port valve you usually dont need a bypass unless the mi,s call for one.

 

[buckley plumb]

what is your view on a combined feed and vent - i was told at college it was a no no but when i picked up a potterton manual it said use combined also glow worm still say you can use combined as long as pipe is 22mm

regards ant

 

[Rodreguez]

i knew a plumber wen piping in a combined would jus do a 22m feed with no vent over tank. i never would do one like this and wen i questioned him he was adament it was ok.

 

[Snuky]

you have combined feed and vent leave them as they are but move to the suction side of the pump , the rad is off the primary which i assume goes to the bathroom rad which is normal as it gives you somewhere to dry the towels all year , if it gets too hot fit a trv to it , if you have a 3 port valve you usually dont need a bypass unless the mi,s call for one.

It would be nice if the rad was in the bathroom, however it is one of the bedrooms. So the always on rad is not there for safty, can it be turned off at the valve? So I have learnt that I can have a combined feed and vent and that mine is on the wrong side of the pump, tipical. What would happen if I did not move the pipe to the suction side of the pump and removed the always on rad?

 

[Rodreguez]

yea can jus turn off on valve, or re-pipe to central heating circuit, or remove its up to you. if you move the combined to right position this would be fine.