Running a combi boiler from a generator?

[Frogwell]

Morning all, First time post here although I've lurked about a bit before looking up information on how to do stuff without overly killing myself.

Living in a rather exposed location on the side of a hill, we tend to have a little more than our fair share our electricity cuts in winter, which never used to be much of a problem when the central heating and water came from the coal stove. However, a few years back I replaced the stove with an oil fired Worcester Bosch combi boiler and now enjoy staggering heating costs, a much colder house and no heating or hot water when we have a power cut. To address the power cuts, I was thinking I could probably use my 2.6kw generator - it would seem to be the logical option. Does anyone know if it's just a case of cutting the main power cable to the boiler, sticking a plug on it and then plugging it into the generator when the power goes off? Or is there more to it than that? I'm assuming the thermostat and control panel for the boiler take their power from the boiler, or do they? Would I need to connect them to the generator separately?

There's also the question of voltage regulation, I know the boiler has an electronic control panel as it needed replacing twice within a month of being installed, but how sensitive are they do the potential fluctuations from a generator? Although presumably just using the computer UPS would sort that?

Obviously the ideal solution would be to have a transfer switch installed by the main electrical panel, but switch cost plus a days work from an electrician put that North of my price range.


Thanks.

 

[Lucien Nunes]

There should be one point of supply, usually a fused connection unit, that feeds the whole heating system. The voltage regulation
should not be a problem if the generator is of reasonable make and running correctly, however the frequency should be fairly close to 50Hz as this affects the fan and pump etc. The most serious issue would be if the generator misfires and slows down while in operation e.g. as the fuel runs out, as the output can then go badly out of spec and cause damage to connected electronics. Your idea to prevent this behaviour reaching the boiler using a UPS is a good one and would also give time to get the genny started etc.

CAUTION: connecting your pemanently-installed C/H to a portable generator raises various questions about earthing. Seek advice from a qualified electrician on the spot, who can see and test the existing earthing arrangement!

 

[Frogwell]

Thanks for the reply Lucien. An electrician fitted a new earth when the central heating was installed a few years back as it turned out that before that nothing in the house was earthed. He connected it to the incoming water pipe and I notice the supplier of the boiler also fitted an earth from the boiler to the same spot. Presumably if I'm cutting the power feed that earth will still exist though as it's separate?

 

[Marvo]

The biggest issues will be for the earthing arrangement of the genset itself. The earthing and bonding of the heating system will remain as it is.

 

[Frogwell]

Ah, I see. No idea about the earth on the generator. Can an external earth be connected to them? Do they need it?

 

[DPG]

I predict an E54 post any time now.... Daz

 

[overskilled]

Frogwell: If you want someone to come and take a look I'd be more than willing, I'm based in Kirriemuir so not massively far away and I could probably figure out a workable solution for you at a reasonable costing.

 

[Frogwell]

Thanks for the offer Overskilled. At some point I may take you up on that if finances ever get back to some sort of normality. At the moment though this recession is just being too unkind to us self employed people.

 

[Engineer54]

The arrangement you speak of is going to be a costly exercise to be honest, and will only add to your central heating/hot water running costs.

If you DO decide on employing the use of a generator, then it needs to be a decent one with electric start that can also supply limited lighting and power needs to your house. In which case it will definitely need to incorporate an AVR. You can employ a manual changeover switch but to be honest an automatic changeover is a far more convenient and better option all round. The cheap gen-set's that are sold by the sheds are of little use in any stand-by household situation, they are basically only any good for site working, running hand power tools, small cement mixers etc, and site lighting needs.

As for earthing of any generator you decide to install very much depends on the design of the generator itself, and will need to be assessed by a competent electrician that knows his way around stand-by generator installs. It's never as easy as it first seems when integrating a generator into a mains supplied system, so don't fall into the trap of thinking that it's a simple exercise, there are safety rules and regulations that NEED to be followed in virtually all circumstances....

 

[DPG]

Eng, it's took you about a week to reply to this thread - your response times are slipping. You can normally smell a generator or earth-rod question from miles away. Daz

 

[telectrix]

china is miles away

 

[DPG]

Good point.

 

[overskilled]

Its the combo of both together....caused a fault condition....

 

[SPARTYKUS]

Eng, it's took you about a week to reply to this thread - your response times are slipping. You can normally smell a generator or earth-rod question from miles away. Daz

He's probably texting Stephen Hawking right now about fabricating some sort of worm hole to allow instant notifications.

 

[Silly Sausage]

He's probably texting Stephen Hawking right now about fabricating some sort of worm hole to allow instant notifications.

Only if it was safely Earthed, or Marsed, or Jupitered or ..........