UPS for CH

[orval]

Hi,

I have a radial circuit supplying my central heating and fridge-freezer. It's connected into the CU via a 6A RCBO on one of the unprotected ways.

Last night we had a power cut for a few hours. So we woke up to no heating or hot water and a defrosting freezer.

Is there a type of UPS available that can be placed in-line in the radial circuit? Do the regs even allow for this? Using a normal plug-in UPS seems wrong.

Cheers

 

[Iggifer]

I think your best plan is to go with a plug in UPS, although I'm not sure what kind of run time you're going to get off one designed for a PC, and one for more industrial purposes are going to be big £££.

You have a radial circuit run off a 6A RCBO? Is there just one outlet on this radial?

 

[ericmark]

A few years back I looked into UPS where I worked for the computers with the idea of one big one to supply all. However the price of one big one was far more than a load of little ones so we went for a load of little ones.

The fridge may defrost but without opening the door a freezer should last 12 hours so either something wrong with freezer or power was off a lot longer than overnight.

It has been a subject for discussion a few times where when a RCD supplying lights as well as other items fails one realises within 12 hours so no problem with freezer but where a RCBO only supplies a few items it can trip without noticing. I know of one guy who has intruder alarm on same circuit as it beeped on power failure to alert him of failure.

There are touches which will auto light with power failure one of those on same circuit may alert you of a failure.

A UPS will only help if you are alerted of the failure or it will just take longer before you see water pool to alert you.

 

[orval]

I think your best plan is to go with a plug in UPS, although I'm not sure what kind of run time you're going to get off one designed for a PC, and one for more industrial purposes are going to be big £££.

You have a radial circuit run off a 6A RCBO? Is there just one outlet on this radial?

Yeah I'm not sure about the runtime. I have a UPS protecting two servers, which I think have 300W power supplies, and they lasted about an hour and a half.

Thinking about it I'm more concerned about the CH, which is probably quite low power.

There are two outlets. A 3A fused spur for the CH and a socket for the fridge.

 

[orval]

A UPS will only help if you are alerted of the failure or it will just take longer before you see water pool to alert you.

Yes, as I said above, I've decided I'm not so concerned about the freezer as it will take time to defrost.

As for being alerted, the UPS I already have beeps when there is no mains supply. It's actually quite annoying!

Your mention of the alarm reminded me that my burgler alarm is actually on this circuit as well. I had forgotten about that. It has a backup battery anyway though so it's not really a problem.

I wonder whether I can just put a plug-in UPS in at point where the CH spurs off?

 

[JohnD]

your boiler is probably fed from an FCU. You can change it to a plug and socket (5A or 3A fuse in the plug) and then you can easily put the plug into a UPS. no need to try to feed the whole circuit from a UPS, anyway, if you did it would backfeed all the other circuits and also the mains supply, which is both illegal and impractical.

 

[ericmark]

Although the CH does have a pump which is of course a motor it's start load is a lot less then the fridge or freezer so one should be able to run central heating for quite a long time.

The size of battery in the UPS will determine how long it will run for with the humble PC normally we only want long enough to finish work in hand and log off as normally lack of lighting means we are limited in what we can do. So batteries are not that big.

In my house we have one central gas fire which does not require electric power for when no electric. Hope we never get no gas as we have no electric heaters.

But I am sure we could soon buy either gas bottle heaters or electric if we had to.

 

[viewer]

A couple of years ago made a system for next door neighbour based on 12v car battery and inverter using relays to sense mains failure/ isolate circuit/ feed circulator. Needed as they have a wood burning stove which boiled if pump failed and we had several outages. It's worked well and uses a solar cell to keep topped up. A bit crude as it doesn't sense whether boiler is hot or not so comes on even if not needed for original purpose, but would be easy to add thermostat if wanted. Using the UPS to control you could add another battery if needed for longer time out and auto recharge.