Do unvented cylinders work in a power cut?

[Mr.B]

As per the title.

If we do happen to experience blackouts then obviously the vented HW Cylinder is gonna be a big bonus (providing the blackouts are temporary and we get some supply, even if only for an hour or so at a a time) ... but having never owned an unvented cylinder I wasn't sure if they need power to work.

 

[denso13]

You need power to heat the water in them, unless you have a solid fuel fire/boiler. But the water will flow from them without power.

 

[terryplumb]

Electric heating elements will not work without electricity ,neither will gas boilers . Irrespective of the cylinder being vented or UNVENTED .

 

[Mr.B]

My point was ... if we have intermittent power cuts then,obviously enough, the boiler will heat the water in the VENTED cylinder when the power was on, and it will be stored for use during periods of outage - and being UNVENTED it will deliver hot water without the need for power (ie, by gravity).

Maybe my question wasn't clear ... does an UNVENTED HW Cylinder deliver water during periods of outage or does it require power to allow delivery of hot water.?

 

[denso13]

But the water will flow from them without power.

 

[Mr.B]

OK, didn't read closely enough - so that's a "Yes" then ... ta for that.

 

[terryplumb]

An UNVENTED cylinder delivers water to taps under water mains pressure. A vented cylinder delivers water to taps under gravity pressure. The electricity has nowt to do with water pressure ,only the heating of the water ,directly or indirectly via a boiler.

 

[Mr.B]

Indeed, I understand what you're saying - ta for that. I think i was just uncertain about it given that there are motorised valves on the unvented cylinder and, having never owned one, wasn't sure if the valve(s) were needed to allow the water to be delivered.

Whilst definitely not intending to resurrect the combi versus cylinder question here, I have to say the possibilty of power cuts does add a little weight to, and reinforce the advantage of, stored hot water versus combi supplied hot water.

 

[Nozzle]

My point was ... if we have intermittent power cuts then,obviously enough, the boiler will heat the water in the VENTED cylinder when the power was on, and it will be stored for use during periods of outage - and being UNVENTED it will deliver hot water without the need for power (ie, by gravity).

Maybe my question wasn't clear ... does an UNVENTED HW Cylinder deliver water during periods of outage or does it require power to allow delivery of hot water.?

Depends how widespread the power cut is. If your local freshwater plant has a power cut, then you won't get any flow through your cylinder. The delivery pumps will come to a griding halt and the system pressure (which includes your cylinder) will decay away...

You'll then be left with static head - which depends on how high up your nearest water tower is, less the dynamic pressure loss of everyone else drawing water and the leaks

Nozzle

 

[Mr.B]

^^^ Yes, quite so.

The word "unprecedented" is now a household word. None of us have ever seen the things we're now seeing. It does make us all consider the possibility of things ocurring that were previously unheard of. And, keeping the topic on a plumbing and heating theme, it has made me wonder if the possibility of (hopefully, managable, power cuts) will have finally made my mind up about whether to go combi or cylinder.

It's currently a very conventional fully pumped, heat only, vented cylinder system here and I was very close to committing to a 35kw (or therabouts) combi (Intergas and Baxi were two names I had seriously considered) but I confess I'm giving it further serious thought.

 

[Nozzle]

If there is long term loss of power and fresh water, civilisation as we know it is toast. Lock-down under COVID-19 is not the end of civilisation as we know it. Keep some perspective to keep yourself happy.

Nozzle

 

[JohnD]

I can only think of one occasion when a watermain burst and my district was without water for about a day. On that occasion my neighbour told me he washed and shaved using water from the WC cistern. I was lucky enough to have a loft tank and could have managed for days if I'd been thrifty.

 

[JohnD]

If there is long term loss of power and fresh water, civilisation as we know it is toast.

Utility companies have good disaster and emergency procedures, including nominated workers and backup locations, and they have strategic stockpiles and distributed depots. They even have PMR because mobile phones may stop working.

Since this is done by the utility companies, I don't think it has been neglected and cut back like the NHS.

In a major incident, the most important thing to have in place is not a warehouse of supplies, but a well-thought out and regularly tested system where key people are familiar with the processes and have used them. Think of Army exercises and preparedness. Think of Civil Defence, as was.

Now think of Jeremy the Hunt.

 

[ericmark]

Yes in a power cut I will have water, but not really potable water, and with no electric it would be hard to boil it, so would have to live on beer.

 

[HERTS P&D]

I would plug the power lead that goes to the boiler electrics into a generator and have heating and hot water without mains electricity. (vented system)

Andy