Switching from Gravity to fully pumped - open vent position?

[SJB060685]

Yeah a corrugated coiled cylinder wouldn't work.

Can you explain why a cylinder like mentioned wouldn’t work on gravity?

 

[EvilDrPorkChop]

Maybe @John.g can explain it better, but I always believed it was because of the resistance it caused along with air getting trapped in the corrugations made them a lot more prone to air-locking.

 

[John.g]

I think that's as good a reason(s) as anything, I might be able to find that long thread and post the link.

 

[SJB060685]

I think that's as good a reason(s) as anything, I might be able to find that long thread and post the link.

It was a long thread and I can remember very little of it.

 

[ShaunCorbs]

Yes due to the internal resistance of the coil manufacturer don’t recommend it for gravity

 

[John.g]

Link

How can I cure my gravity circulation problem? > Plumbing Advice - PlumbersForums.net

Find How can I cure my gravity circulation problem? Advice and Help. How-to How can I cure my gravity circulation problem? in the Central Heating Forum advice boards on PlumbersForums.net | Plumbing Advice for All. How can I cure my gravity circulation problem? on PlumbersForums.net Plumbing and...

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[AndreGH]

Thank you for all the feedback, we bit the bullet and moved the vent and feed, wasn't the easiest fit as it was so tight but we got there and all is working perfectly now. Also had hot water inside half hour of it being turned on as opposed to the several hours with the gravity system lol

 

[John.g]

Where did you move the vent and feed to? (which one of the schematics?)

 

[AndreGH]

Where did you move the vent and feed to? (which one of the schematics?)

As per John G's reply.

 

[John.g]

That's either the VCP method or the combined cold feed and vent like my own.
To put the advantage(s) of the fully pumped vs the gravity system in perspective and assuming the HW cylinder is ~ 2.5M above the boiler then the circulating head is ~ 0.023M with the gravity method vs ~ 2/2.5M with the fully pumped method so easy to see the reason for the the vastly improved cylinder warm up time.