Changing Indirect Hot Water Cylinder

[Solderedjoint]

Just about to order 1050x500 replacement hot water cylinder..
My question….What’s the most successful way of removing the existing cylinder,
Once I’ve isolated the cold feed to cylinder and feed to heating circuit?
This cylinder is in the loft by the way

 

[Nige F]

brute force and ignorance....has stood me in good stead for 30 years

 

[Solderedjoint]

Thought their maybe someone who had an easy way of emptying cylinder (no drain off tap) Could I end up with a air lock in the heating circ once reconnected, no automatic air vent fitted, should I fit one?

 

[kevplumb]

hose pipe and syphon it out

after removing the top union of course

 

[pedmon]

Turn off your water at the mains. Then run you hot tap until there nothing left. That should empty your cylinder.

 

[ACOperson]

Pedmon, that won't drain the cylinder mate, only the pipework.

Siphon the best way. You can do this with an aquavac or a pair of lungs.

 

[Solderedjoint]

Turn off your water at the mains. Then run you hot tap until there nothing left. That should empty your cylinder.

Empty Tank….full Cylinder think you’ll find….
Aqua-vac it is then
I’m actually more concerned about the airlock possibility once I reconnect the flow and return is a AAV the answer, should they always be fitted?

 

[ACOperson]

Yes, airlock on systems: my favourite thing

AAV may help avoid this but it has to be out in the right place. If put in the wrong place then you can end up with the AAV sucking air in!!

Maybe just a manual air vent (air pip) better if you're doing it yourself.

 

[Solderedjoint]

Cheers ACO, without seeing it again I’m guessing/must be that the heating circ is vented back to the F & E tank

 

[ACOperson]

It will be vented to F&E, but thats only to deal with expansion, not usually to vent air.

Some systems use a 22mm feed pipe to vent air, others have nothing and seem to work fine, unless its me re-filling them in which case they all airlock.

If there is a convenient place on the +> side of the pump at a high level then you may be able to install an AAV.

 

[beermatt3]

I always put a couple of feet of 15 copper tube in the end of the hose, then you can feel it touch the bottom, otherwise your hose may coil around and float to the top.

Top tip, I reckon.

I think airlocks are what sorts the men from the boys. You can't learn how to clear an airlock at college.

What's the longest time anybody has spent on an airlock, can you beat 2 days?

Matt

 

[ACOperson]

Longest I've spent is maybe a couple of hours: system boiler with flow & return rising from boiler and with small horizontal section on top. No drain off on flow/return above boiler, no air vents anywhere.

 

[Solderedjoint]

Where is the best place to drain off the water in the hot water heating circ, at this stage (until I can get stuck in Monday) I’m unsure whether it’s a Y or S plan.
I’m thinking close all the Rads, then drain from a Rad on the ground floor (cylinder in loft) making sure valve in the hot water/heating position…….Is this the best way?

 

[corgiman]

i would close the rads as you may get an airlock

i would drain down for the lowest point and open the rads bleed points to allow air in so to remove the water

nowt like getting stuck in then hearing a gurgle and getting your tools wet

 

[ollski]

My question….What’s the most successful way of removing the existing cylinder,

Leave the ****** a note to let them know you want to get rid of it

You're not going to get much of an airlock in a cylinder in the loft, you will only need to syphon the water out of the hot tank and drain the circuit to just blow the bottom connection.