New cylinder but no gravity fed hot water

[SwiftNick54]

I replaced my hot water cylinder at the weekend, it is an indirect cylinder. The indirect feed and return are 28mm pipe to 1" connections, the upper hot pipe has a bleed vent which you unscrew to remove air, the lower pipe does not. Apart from that it has an immersion heater, cold feed at the bottom & hot out at the top.
The system is connected to a Ideal Mexico RS80 boiler, the rads which are working OK are pumped, but the 28mm feed and return to the cylinder are gravity fed.
The system is very simple and old, not tank stat, just a pipe in and a pipe out.
So the rads work OK and I have bled the air. I bled the upper indirect connection to the cylinder & the hot water from the boiler gets this far, but it does not appear to enter the cylinder as the water & bottom return are cold.
I am thinking that it is an airlock, but does anyone have any ideas what the problem could be and how to solve it.
Many thanks Nick

 

[steve32]

Have you fitted a gravity cylinder or is it a part L fully pumped cylinder.
If it is not a gravity cylinder you need to change it some times fully pumped cylinders will work on a gravity system but take longer to heat.
Gravity cylinders often have to be ordered from a plumbers supplier and cost approx £300.00.

 

[SwiftNick54]

Steve,
It as a part L, I did not know you had specific gravity fed cylinders, I have never done one before. I am using the immersion at the moment as everyone wants the water hot, but tomorrow I will drain the cylinder & see how long it takes to warm up. Earlier today it did not appear to warm up at all.
Thanks Nick

 

[dcawkwell]

You have fitted a modern cylinder. It won't do gravity hot water.
You'll need to go fully pumped.

 

[dcawkwell]

Steve,
It as a part L, I did not know you had specific gravity fed cylinders, I have never done one before. I am using the immersion at the moment as everyone wants the water hot, but tomorrow I will drain the cylinder & see how long it takes to warm up. Earlier today it did not appear to warm up at all.
Thanks Nick

It won't work. Or waste an awful log of gas trying to do it.
Fully pumped that cylinder will heat up in about 30 minutes.

 

[oilhead]

Your cylinder is not suitable for gravity hot water; very few are these days. High recovery cylinders are only suitable for pumped systems.

 

[oilhead]

All of us together!!!!!!! A phone call interrupted my draft sorry not to have noticed.

 

[SwiftNick54]

What is my best (least expensive) way out, excluding using the immersion, to convert to fully pumped or ditch the cylinder and get a new one which is OK for gravity feed?
Thanks Nick

 

[dcawkwell]

What is my best (least expensive) way out, excluding using the immersion, to convert to fully pumped or ditch the cylinder and get a new one which is OK for gravity feed?
Thanks Nick

Cap off the gravity flow pipe from the boiler.
3 port valve on the flow from the boiler to central heating and hot water cylinder + a little wiring. Sorted.

 

[SwiftNick54]

Thanks, looks like a good way out.
Nick

 

[xr4x4]

What is my best (least expensive) way out, excluding using the immersion, to convert to fully pumped or ditch the cylinder and get a new one which is OK for gravity feed?
Thanks Nick

Cap off the gravity flow pipe from the boiler.
3 port valve on the flow from the boiler to central heating and hot water cylinder + a little wiring. Sorted.

Cap off?

What about the water in the pipe? Won't it boil?

Couldn't you just stick a pump on the gravity circuit?

 

[dcawkwell]

What is my best (least expensive) way out, excluding using the immersion, to convert to fully pumped or ditch the cylinder and get a new one which is OK for gravity feed?
Thanks Nick

Cap off the gravity flow pipe from the boiler.
3 port valve on the flow from the boiler to central heating and hot water cylinder + a little wiring. Sorted.

Cap off?

What about the water in the pipe? Won't it boil?

Couldn't you just stick a pump on the gravity circuit?

Yes pump on gravity side would do it. But not the normal way.