venting suggestions

[stanman1]

hi all, im a newby so forgive me if i make any boo boos whilst posting i am helping a friend install a central heating system and i have run into a problem on venting! the system is all on one level the cylinder is right next to the oil fired condensing boiler. as the flow and return pipes feeding the coil in the cylinder are lower than the outet flow and return on the boiler will i need to build in some air bottles at the high spots on the boiler. i already have a cold feed going into the return at the cylinder an air bottle to bleed the heating flow at the cylinder and an open vent on the flow at the cylinder where it goes ito the top pipe of the cylinder (i.e. DHWflow). i know this sounds complicated but when i have done instalations before its always been where the boiler has been lower than the cylinder like in a conventional house! this has got me flummoxed because its looking like i might have to put in two open vents if i cant use the air bottle system! regards, stanman

 

[swbjackson]

Your pipe configuration is completely wrong for a fully pumped system. Cold feed and open vent adjacent to the cylinder should be used for gravity hot water systems.

Why are you fitting an open vented system anyway? Most people plump for a sealed system on a new install, there much less prone to corrosion problems.

If you insist on going the open vent route you need a close coupled feed and vent configuration on the flow between the pump and the boiler.

 

[stanman1]

Your pipe configuration is completely wrong for a fully pumped system. Cold feed and open vent adjacent to the cylinder should be used for gravity hot water systems.

Why are you fitting an open vented system anyway? Most people plump for a sealed system on a new install, there much less prone to corrosion problems.

If you insist on going the open vent route you need a close coupled feed and vent configuration on the flow between the pump and the boiler.

my friend insists on an old fashioned system, so what do you do? anyway that still doesn't get round the air lock problem at the cylinder! if i do a close coupled f.e. at the boiler i still have high spots on the return at the boiler and at the cylinder flow to the heating and the cylinder coil on both sides of the 3 port valve. would air bottles be ok here? then i could vent them on filling the system and show him what to do if air trpped there. any suggestions? i will take some pics today so you can get an idea of the layout. its been years since i did heating everything is combi boilers these days, cheers, stanman

 

[stanman1]

Your pipe configuration is completely wrong for a fully pumped system. Cold feed and open vent adjacent to the cylinder should be used for gravity hot water systems.

Why are you fitting an open vented system anyway? Most people plump for a sealed system on a new install, there much less prone to corrosion problems.

If you insist on going the open vent route you need a close coupled feed and vent configuration on the flow between the pump and the boiler.

hi mike, ive just checked the drawing that came with the honeywel 3 port valve and it clearly shows the cold feed on the return! admittedly it is near the boiler but as the boiler and cylinder are next to each other i thought that my pipe position would be ok. it shows the vent near the boiler which is the way i had done it. surely they wouldnt put that in print if it were wrong? the diagram is for a y type system install. regards, stanman

 

[45yearsagasman]

The correct configuration is Boiler, Open vent, Cold feed, Pump, in that order on the flow pipe. Any other setup is not correct. Yes, I realise you can connect feeds and vents onto the boiler and in other places, but it will not be correct. The position of the feed and vent is vital so as not to aerate system.
If this a new system, why are you still insisting on open vented, and not sealed?