Mains feed and vent pipe on vented system

[Matt0029]

I have a boiler to swap on a vented system. The open vent was presently attached straight to the boiler. And the cold feed is tee'd in to the hot water return near the coil. When I install the new boiler (it's staying vented). Would I be best off changing the cold fill postion I will obviously need to alter the open vent as it did originally tee straight off the boiler.

 

[Matt0029]

With a view to possibly changing it to what it states in the new boiler manufactors instructions.

 

[ShaunCorbs]

Sounds like it was gravity hot water

and yep either need to adjust one or convert to sealed

 

[Matt0029]

Sounds like it was gravity hot water

and yep either need to adjust one or convert to sealed

Thanks. The primary flow is tee'd off the central heating flow after the pump. With a zone valve on the primary flow. So don't think it is gravity hot water at present. Does that sound correct?

 

[ShaunCorbs]

It’s prob been semi converted

 

[Matt0029]

Thanks so if I keep vented I should really change the cold feed postion? I need to change the vent anyway. Can I ask the reason for the inverted cold? Is it to stop water pumping back in to the head tank? Thanks

 

[ShaunCorbs]

Anti gravity loop, stops gravity flow back upto the tank

 

[Matt0029]

Been looking through some of my old level 3 books. That shows the cold feed to the system tee'd in to the primary return on a gravity hot water system same. Was this done to try and make the primarys circulate more?