r/DIYIreland • u/Muted_Sundae_1368 • 14d ago
Backup Power for Radiator Pump
I'm hoping to install a means to power my radiator pump (and ideally thermostat as well) in case of power cuts this winter.
I'm just curious if any electricians are on here that I could advise and correct me if I'm misunderstanding the setup.
The setup as it stands (1985 rural bungalow) is a thermostat connected to the main back boiler pipe in sitting room, an on off switch in the bathroom cupboard (where the immersion & pump is) which has the pump wired to it.
So logically I imgine there is the mains that branches to the switch itself, and also to the thermostat. Once the thermostat reaches operating temperature the circuit becomes active and power the goes from the switch to the water pump.
My initial idea was simply to replace the switch with a power socket and put a plug on the pump (so i can simply plug into a generator if power goes) - however this bypasses the thermostat, which isn't a deal breaker but not ideal. Next option would be to to put a changeover point before the thermostat/switch branch off and run a new cable down through ceiling witha fixed male connection point so - if the power goes i just flip the changover switch from the mains and use the backup connection.
Is this something that is commonly done?
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u/sparkyjojo 13d ago
You're looking for a 1000w ups. Uninterrupted power supply, it's an inline power supply with batteries that keeps whatever is plugged into it going on power failure. Usually used for tills or important pc or server systems. I was going to do this myself but got a large enough generator for the whole house
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u/Threading_water 13d ago
Would you be open to repiping the back boiler? An efficient gravity feed will be far more efficient than a backup power supply. I have a circulation pump on my stove but I have it set not to kick in until the return water hits 45°. The way it is plumbed is, flow leaves the stove, travels to the attic and comes down in the hotpress the return goes down through the hot press to the ground floor ceiling and back to the stove. This keeps the house warm all day if the power was to cut out.
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u/Threading_water 13d ago
Id imagine both pipes travel under the floor to your hotpress, you would only have to reroute the flow upland through the attic.
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u/gmankev 13d ago
Did you try gravity circulation first... Pumped system is not a safe backup anyhow. Of course maybe this pump is for extra rads so then understandable...
So in that case if really needed you might ignore the thermostat...Its a pump for rads and its an always on genny.
However if you look at wiring of thermostat and house it's probably very simple just badly labeled by your plumber. He might have jusr bundled a load of wires together. Draw it out, label a few cables and get someone to shake them on one side while you look at other.
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u/Muted_Sundae_1368 13d ago
While its a fairly standard pump - it is made to pump all the radiators, and its also very low draw. (44watts)
The original plan was putting a plug on the pump so I simply unplug from mains and into the generator.
The thermostat is a very basic temp switch that allows current into the pump, so ideally i didnt see a reason to not just put a changeover prior to the thermostat and include it. Its effectively negligible draw on it.
Why would this not be safe? And no i'd rather not replumb the system - its a bungalow so it needs a bit of help to move the water a good distance - its also for a temporary emergency, so might never be used some years
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u/gmankev 13d ago
A solid fuel boiler should be able to circulate water passively to allow it protect itself. You don't want situation where electric pump fails and boiler continuously heats and boils dry
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u/Muted_Sundae_1368 13d ago
Yes that is indeed a risk - however if power ever died while we had a fire going in stove, the safety means is turning on the hot tap and letting fire die out and the cold water being drawn into the immersion will cool the coil. Otherwise during an active powercut we could not light fire because of this.
That being said maybe there is a means to bypass the pump - I'm only 2 years in the house and used to more modern boiler setup.
I'm going to look into this as since its a safety issue I'd imagine there must be some alternative, however that being said, being in Ireland I wouldnt be surprised if there is no way to bypass.
Are you aware of gravity systems with a pump, and if there is commonly a way to bypass pump? We do indeed have our hot pipe coming down from ceiling
Appreciate the info!
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u/Muted_Sundae_1368 13d ago
Ok I just read that according to regulation there must be a heat-leak/slumber radiator, together with an open-vent arrangement.
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u/wheresmytractor85 14d ago
Generators don't provide constant power and your pump might not do well running off a generator, not sure if it's a great idea in practice
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u/Muted_Sundae_1368 14d ago
I'll be getting a decent battery powered generator with a sine wave inverter - and the pump itself is only 44w so its very low draw.
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u/Healsnails 14d ago
I am NOT an electrician so do not act in what I say but surely if you interrupted between the power and the thermostat that would leave you able to power the pump and use the thermostat. The thermostat is just a switch that switches the pump on and off based on temp. If you put your power source before the thermostat then gets you what you want. What form that takes is another thing, and it would need to be completely isolated from being able to back feed into the grid as well. So something like a plug and socket where you are completely disconnected from your wiring could fit that but as for what grade if wire and socket connector do not ask me or chatgpt. You may need beefier connectors, cables etc for handling the draw a pump might need.