After arranging a lunchtime barbeque in a couple of weeks time (to celebrate
a wedding anniversary) the power company has informed us that there will be
a power interruption from 8.30am to 4.30pm on the day (possibly longer if
they meet any snags) so my question is this: am I right in thinking that a
850watt 2 stroke generator would be powerful enough to power the condensing
combo boiler to give us hot water (maximum power consumption 140watt) and
maybe some small electrical appliances all well under 1kw?

DIY wrote:
After arranging a lunchtime barbeque in a couple of weeks time (to celebrate
a wedding anniversary) the power company has informed us that there will be
a power interruption from 8.30am to 4.30pm on the day (possibly longer if
they meet any snags) so my question is this: am I right in thinking that a
850watt 2 stroke generator would be powerful enough to power the condensing
combo boiler to give us hot water (maximum power consumption 140watt) and
maybe some small electrical appliances all well under 1kw?



Yes, should be no problem. I presume you would want to keep your
fridge/freezer going as well? Best to plan not to have to open the
fridge/freezer too often, just in case.

If you could plan your day to only need the central heating, you could
beg/borrow/steal a leisure battery and a 300W inverter and do without
the genset.

Dave Osborne wrote:
DIY wrote:
After arranging a lunchtime barbeque in a couple of weeks time (to
celebrate a wedding anniversary) the power company has informed us
that there will be a power interruption from 8.30am to 4.30pm on the
day (possibly longer if they meet any snags) so my question is this:
am I right in thinking that a 850watt 2 stroke generator would be
powerful enough to power the condensing combo boiler to give us hot
water (maximum power consumption 140watt) and maybe some small
electrical appliances all well under 1kw?


Yes, should be no problem. I presume you would want to keep your
fridge/freezer going as well? Best to plan not to have to open the
fridge/freezer too often, just in case.

If you could plan your day to only need the central heating, you could
beg/borrow/steal a leisure battery and a 300W inverter and do without
the genset.

Sorry, for "central heating" read "hot water". I.e. your boiler will run
off an inverter no probs.

On Thu, 18 Jun 2009 18:24:38 +0100, Dave Osborne wrote:

Yes, should be no problem. I presume you would want to keep your
fridge/freezer going as well?

An 850W genset might struggle to start a larger fridge/freezer
especially if it already has some load on it. Rule of thumb, motors
need 2 to 3 times their rated power to start.

Inverter and battery is another solution but difficult to "refuel"
once the battery is flat. The genset can just have some more
petrol/oil poured in...

--
Cheers
Dave.

In an earlier contribution to this discussion,
DIY wrote:

After arranging a lunchtime barbeque in a couple of weeks time (to
celebrate a wedding anniversary) the power company has informed us
that there will be a power interruption from 8.30am to 4.30pm on the
day (possibly longer if they meet any snags) so my question is this:
am I right in thinking that a 850watt 2 stroke generator would be
powerful enough to power the condensing combo boiler to give us hot
water (maximum power consumption 140watt) and maybe some small
electrical appliances all well under 1kw?

It's *powerful* enough - but whether it will drive your boiler depends on
the quality of the output (voltage stability and waveform) and how fussy
your boiler is. Another consideration is whether you really want a 2-stroke
engine screaming away the whole time.

As others have said, you *may* be able to power it from an inverter
connected to a decent leisure battery - but do the sums to see whether you
have sufficient capacity.

If you *must* use a generator, a 4-stroke jobby with inverter output (like
those made by Honda) would be a better bet. Those are *much* quieter, and
have very stable outputs - probably better than the mains!

Oh, and if the boiler has spark ignition, and uses flame ionisation, you may
need to strap the generator's neutral and earth wires together to get it to
fire. And for good measure, use an RCD at the genny end of your extension
lead, and connect the genny's earth to an earth spike.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In message , Dave Osborne
writes
DIY wrote:
After arranging a lunchtime barbeque in a couple of weeks time (to
celebrate a wedding anniversary) the power company has informed us
that there will be a power interruption from 8.30am to 4.30pm on the
day (possibly longer if they meet any snags) so my question is this:
am I right in thinking that a 850watt 2 stroke generator would be
powerful enough to power the condensing combo boiler to give us hot
water (maximum power consumption 140watt) and maybe some small
electrical appliances all well under 1kw?

Yes, should be no problem. I presume you would want to keep your
fridge/freezer going as well? Best to plan not to have to open the
fridge/freezer too often, just in case.

If you could plan your day to only need the central heating, you could
beg/borrow/steal a leisure battery and a 300W inverter and do without
the genset.

He'll need to get the earthing right if he wants the boiler to flame
sense

Also - some boiler pcbs are not well designed (to say the least) -
"dirty" mains might kill the pcb, be warned

If you want hot water - fill a cauldron - and heat it over a camp fire,


--
geoff

DIY wrote:

am I right in thinking that a
850watt 2 stroke generator would be powerful enough to power the condensing
combo boiler to give us hot water (maximum power consumption 140watt) and
maybe some small electrical appliances all well under 1kw?

All at once? Possibly not, depending on what you mean by "well under
1kW". I'd say 500W is "well under 1kW", wouldn't you? But that generator
won't power 2x500W.

The other thing you need to know is that the generator isn't 850 watt.
It may be plated at 850VA which isn't quite the same thing. And that
rating will be a maximum and the generator will probably be closer to a
450VA generator. If it's one of the two stroke generators with an
auxilliary 12V output then it doesn't really matter what it's badged as
or what the claim is for output, it wil be a 450VA generator. I've got
one (badged Cosmo, identical to the Wolf/NuTool/Pro User/Munro etc.) and
it's OK for running a drill, powering a few lights in a barn, recharging
a tractor battery, operating a TV, and charging a laptop while running a
printer. It could certainly power a water pump/boiler for a time.

Just don't expect to power multiple items simultaneously, it won't do
it. That 850W figure indicates that it can handle a transient switch on
load of 3.5 Amps. Try to maintain that continuously and you would damage
the generator. I've seen them with burnt-out windings, melted insulation
and damaged sockets from trying to run at 3A continuously. If you try to
run a load of 2A you will hear the engine labouring.

If you want a cheap stop gap, they are usable. Two strokes are also
ideal for standby use since they are robust, almost maintenance free and
you can put it in a garage for years on end and as long as you keep it
dry it will run fine when you fill and prime it.

If you do store it remember to drain the carburettor, because if the
fuel evaporates the carburettor will be fouled by the two stroke oil
residue and then it will be a bugger to get started next time around.

On Thu, 18 Jun 2009 21:08:01 +0100, Roger Mills wrote:

If you *must* use a generator, a 4-stroke jobby with inverter output
(like those made by Honda) would be a better bet. Those are *much*
quieter, and have very stable outputs - probably better than the mains!

And have price tags 10 times that of a 850W two stroke. They are
very nice though.

Oh, and if the boiler has spark ignition, and uses flame ionisation, you
may need to strap the generator's neutral and earth wires together to
get it to fire. And for good measure, use an RCD at the genny end of
your extension lead, and connect the genny's earth to an earth spike.

And fit a 13A plug (correctly fused) and socket into the mains feed
to the boiler. It'll almost certainly be fed direct from it's own way
in the consumer unit or via switched fused connection unit off a ring
main.

--
Cheers
Dave.

In message et, Dave
Liquorice writes
On Thu, 18 Jun 2009 21:08:01 +0100, Roger Mills wrote:

If you *must* use a generator, a 4-stroke jobby with inverter output
(like those made by Honda) would be a better bet. Those are *much*
quieter, and have very stable outputs - probably better than the mains!

And have price tags 10 times that of a 850W two stroke. They are
very nice though.

Oh, and if the boiler has spark ignition, and uses flame ionisation, you
may need to strap the generator's neutral and earth wires together to
get it to fire. And for good measure, use an RCD at the genny end of
your extension lead, and connect the genny's earth to an earth spike.

And fit a 13A plug (correctly fused) and socket into the mains feed
to the boiler. It'll almost certainly be fed direct from it's own way
in the consumer unit or via switched fused connection unit off a ring
main.

Boilers usually are fed from a 3A fuse, look in the manual (despite
this, some boiler ocbs have 4A fuses in them !)
--
geoff

"DIY" wrote:
After arranging a lunchtime barbeque in a couple of weeks time ...

Thanks for all the advice and info, it looks like connecting my boiler to a
cheap generator risks damaging the electronics so it isn't an option.
DIY (Damage It Yourself)

DIY wrote:

Thanks for all the advice and info, it looks like connecting my boiler to a
cheap generator risks damaging the electronics so it isn't an option.

A lot of small generators have a 12v output (intended for battery
charging?) and inverters (meant for car use) can be relatively cheap
these days. I wonder if connecting the two together would produce stable
power (albeit less of it)?

Pete

"Pete Verdon" wrote:
A lot of small generators have a 12v output (intended for battery
charging?) and inverters (meant for car use) can be relatively cheap these
days. I wonder if connecting the two together would produce stable power
(albeit less of it)?

Pete

Thanks, I hadn't thought of that.

On 18 June, 14:45, "DIY" wrote:

850watt 2 stroke generator would be powerful enough to power the condensing
combo boiler to give us hot water (maximum power consumption 140watt) and
maybe some small electrical appliances all well under 1kw?

Yes, but a bad idea IMHO.

Go for an inverter to power the boiler, but use a decent one with a
reasonable output waveform and test it beforehand. Otherwise just
don't bother - set up alternative hot water supplies instead as I
doubt you'll need heating. A big insulated plastic "tea urn" cooler
can be handy here, especially if it has a tap.

A British Army "Boiling Vessel" (look it up) is a great gadget for
this situation, and will run off a pair of car batteries. Try eBay or
a big (on-line) surplus shop

For the fridge, use "stored cold" in freeze packs.

Anything else, use a primary power source rather than generating
electricity and then using that, i.e. oil lanterns or candles, gas
stoves for cooking / hot water, wood stove for warmth.

Generators are noisy. If you really must, hire a _quiet_ 4 stroke,
rather than buying a Happy Shopper 2 stroke or a 2kW builder's genny.
The "market trader" gen sets are a lot better noise-wise and most hire
shops will have one.

In an earlier contribution to this discussion,
Dave Liquorice wrote:

On Thu, 18 Jun 2009 21:08:01 +0100, Roger Mills wrote:

If you *must* use a generator, a 4-stroke jobby with inverter output
(like those made by Honda) would be a better bet. Those are *much*
quieter, and have very stable outputs - probably better than the
mains!

And have price tags 10 times that of a 850W two stroke. They are
very nice though.

Yes, although I see that Machine Mart are doing a Clarke 1kW 4-stroke
inverter-generator for under £300 - which is a lot cheaper than the
equivalent Honda, and may well be OK.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Andy Dingley wrote:
On 18 June, 14:45, "DIY" wrote:

850watt 2 stroke generator would be powerful enough to power the
condensing combo boiler to give us hot water (maximum power
consumption 140watt) and maybe some small electrical appliances all
well under 1kw?

Yes, but a bad idea IMHO.

Go for an inverter to power the boiler, but use a decent one with a
reasonable output waveform and test it beforehand. Otherwise just
don't bother - set up alternative hot water supplies instead as I
doubt you'll need heating. A big insulated plastic "tea urn" cooler
can be handy here, especially if it has a tap.

A British Army "Boiling Vessel" (look it up)

I did & found http://www.arrse.co.uk/wiki/The_Army_Rumour_Service

Funny!




--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

In article ,
geoff wrote:
Also - some boiler pcbs are not well designed (to say the least) -
"dirty" mains might kill the pcb, be warned

I know inverters don't produce a true sine wave - but wouldn't a basic
generator be pretty good if kept within its ratings?

--
*Income tax service - We‘ve got what it takes to take what you've got.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 20 Jun 2009 10:31:15 +0100, Dave Plowman (News) wrote:

Also - some boiler pcbs are not well designed (to say the least) -

"dirty" mains might kill the pcb, be warned

I know inverters don't produce a true sine wave

Some do, some produce a "modiyfied sine wave" others are square wave
releying on the connected kit to "shape" it.

- but wouldn't a basic generator be pretty good if kept within its
ratings?

Probably but when a (reactive?) load switches off (ie a motor) there
can be quite a large voltage spike until the genset throttles back.
Similary when a load comes on a dip until it throttles up.

Not quite like the gensets we are used to Dave, 100kVA with only a
30kVA load, even banging a 5k on is taken up by the fly wheel... B-)

--
Cheers
Dave.

On Fri, 19 Jun 2009 16:50:42 +0100, Roger Mills wrote:

Yes, although I see that Machine Mart are doing a Clarke 1kW 4-stroke
inverter-generator for under £300 - which is a lot cheaper than the
equivalent Honda, and may well be OK.

Interesting I might wander over and have a look to see if they have
something in the 2 to 3 kVA range. Though I sometimes wonder about
reliablity, with electronics and changing reative loads. A dierctly
connected alternator won't worry to much about short over/under
voltage but bits of silicon tend to let the magic smoke out if pushed
hard for even a very short time.

--
Cheers
Dave.

In article et,
Dave Liquorice wrote:
Probably but when a (reactive?) load switches off (ie a motor) there
can be quite a large voltage spike until the genset throttles back.
Similary when a load comes on a dip until it throttles up.

Not quite like the gensets we are used to Dave, 100kVA with only a
30kVA load, even banging a 5k on is taken up by the fly wheel... B-)

Heh heh - remember having a low loader car rig. With one of those nice
Honda 5kW (IIRC) generators on board. Lighting was bashing two 1.2 HMI
through the windscreen - and had all the video stuff fed off it too. I was
running off batteries. Sparks 'saved' the HMIs at the same time and took
out the vision trolley PS - and the Digibeta too. While I whistled softly
to myself. Good for overtime, though.

--
*You never really learn to swear until you learn to drive *

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes
In article ,
geoff wrote:
Also - some boiler pcbs are not well designed (to say the least) -
"dirty" mains might kill the pcb, be warned

I know inverters don't produce a true sine wave - but wouldn't a basic
generator be pretty good if kept within its ratings?


The filtering on some boiler pcbs is pretty primitive,and when you just
have a C-R dropper to the electronics and no regulator, transients have
little problem to get through

--
geoff