Planning for winter - can I run my combi boiler off a genny?

Discussion in 'Electricians' Talk' started by jimwillsher, Aug 18, 2011.

  1. jimwillsher

    jimwillsher Member

    Hi all,

    We moved into this house a few months ago. We're told by neighbours that last winter they were without power for three days during a spell of minus 12. The house is quite rural, and if the power cut is due to snowfall then we'll be pretty much housebound with no source of heat.

    We're also mindful that when we moved in we had TEN burst pipes as the house had been left cold over the winter (the vendors picked up the tab for that...).

    We have a Worcester Heatslave 20/25 combi boiler which is wired into a fused switch and then into the CU.

    Is it safe for me to replace the fused switch with a single 3-pin socket and put a fused plug on the end of the cable? For 364 days of the year it would operate as it does now. However come the day of the power cut, would I then be able to unplug it and put it straight into bog-standard petrol generator to keep the boiler running? If so, will I need any particular type of genny?

    You'll gather that I'm not a spark but this seems the best place to ask.


  2. balchy

    balchy New Member

    I live in an area prone to power cuts. Lost power for 3 days over winter and did what your suggesting, sparked my genny up and plugged the heating in, no sense freezing your nuts off. No huge power demand so any genny should do it.
  3. seneca

    seneca Screwfix Select

    The highest current draw will be the pump and as most boilers run off a 3amp fuse I can't see any problems.
  4. proff

    proff New Member

    No problem whatsoever but the plug must contain a 3 Amp fuse to comply with gas regs. :)
  5. jimwillsher

    jimwillsher Member

    Thank you to you all, much appreciated.
  6. J.P.

    J.P. New Member

    Whatever you do don't run the genny in the house Jim..outside under a shelter would be the ideal way of doing things tbqh.
  7. sinewave

    sinewave Screwfix Select

    You need a quiet and economical Genny as you maye require it to run 24/7 untill power is restored so I'd be looking at one of the latest Inverter units.
  8. sinewave

    sinewave Screwfix Select

  9. jimwillsher

    jimwillsher Member

    Nice, but beyond the budget unfortunately :-(
  10. jimwillsher

    jimwillsher Member

  11. Pink Panther

    Pink Panther Member

    The circulating pump is likely to be the biggest drawer of leccy in your CH system but even that - along with the boiler valve, motorised valves and controls, etc - are unlikely to be drawing much more than one amp or so (but worth confirming.)

    Here's an idea you might want to consider; as well as your generator, buy a 300-500W inverter that runs off 12V batteries, cost - around £25. This should be more than enough to run your CH for a good few hours from a single car bettery charge. A bit of a faff maybe, but it'll be completely silent! A couple of batteries will obviously double the running time, or you could have the second battery on charge from your gennie in the garage and do swaps.

    Mind you, if you lose all leccy power, you'd probably want your gennie running for lights and stuff anyways, so might as well just run a cable through to it...
  12. spinlondon

    spinlondon Well-Known Member

    The only thing I would suggest, is that first you contact the Combi Boiler manufacturer, to check.
    There may be sensitive circuitry that may be damaged from overvoltage, or fluctuations of frequency.
  13. sinewave

    sinewave Screwfix Select

    Jim, in your opening post you mention that it's quite possible that you may get cut off for day's?

    If so then you'd do far better investing in a genny like the one I linked to.

    Small low power domestic gennies are not designed for prolonged high load use and if you are off for days you'll be glad of the extra capacity of a bigger unit so you can run sockets, lights and low load appliances along side your heating system.

    Your only talking £600 more plus fitting, it's not much for peace of mind in my view. 
  14. Pink Panther

    Pink Panther Member

    Ooooh, look at you, Mr Moneybags...
  15. J.P.

    J.P. New Member

  16. jimwillsher

    jimwillsher Member

    I'll think it through. You're right, it would make sense, but it's not cash we have spare right now. I'll mull it over for a few days.....

    Cheers everyone,

  17. J.P.

    J.P. New Member

    I reckon that Screwfix genny would be ok - it seems after the boiler is lined in to the genny that there is enough power left to run a TV, radio, a small amount of lighting and possibly a fridge freezer..kettle?..probably not, but you can use a primus or summit in that ilk Jim. Rural life must be brill, wish me missus would let me sell the house to move into the wouldn't bother me if power cuts happened and stuff..all part and parcel of rural life really. An Aga and gravity springs to mind with ref to CH and stuff..;)
  18. Lokkars Daisy

    Lokkars Daisy New Member

    Yeah right ! and what will be their reply

    A) yes go ahead our equipment is fully guarenteed against high voltages etc
    B) we can not guarentee our equipment unless it operates ......

  19. J.P.

    J.P. New Member

    Do you suffer with power downs Jed Clampit ? I mean does the main power cable from the mainland to your island ever break or stuff?
  20. Lokkars Daisy

    Lokkars Daisy New Member

    **** no! we are at the forefront of generation techniques JP   and tv is now 625 lines with colour and Ready Steady Go

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