Worth replacing an old oil boiler?

My house was built in the mid fifties, the bottom half is cavity, the top half is tile hung block.

Unless the rads were one the small side to start with, I suspect this is less of an issue in many cases. Most systems are only running part load for a good part of the heating season, and that is where the condensers gain...

When I fitted a condenser here I left most of the rads untouched (apart from one room that was never really warm enough). My system is weather compensated, and quite often runs flow temperatures under 50 deg C, and so gets full condensing efficiency (which ideally needs return temps under 54 deg c). So there would have been no benefit in larger rads other than on the very coldest days.

My previous solid wall place was built in 1956

I passed what I always assumed was a small wind generator today, it was spi nning like a top. Yet only a light breeze... something is not adding up. I reckon it's a fake, and doesn't generate a thing.

NT

Yes, but you need a weather comensating controller to do that, if it's not then the water temperature will stay high, just not on for very long. An old system isn't likely to have a weather compensating controller.

Yes, mines running at 34C at the moment (although the heat's coming from a thermal store, the boiler was last lit 3 days ago - and doesn't condense anyway).

Without weather compensation it will run at a fixed temperature which you can control. So if you set the flow temp at something sensible (say

I just checked ours, its 13 deg outside here at the mo. The boiler is currently running a flow temp of 41 deg C

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Or computer programming (2+2=5 #but only for large values of 2). :-)

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Possibly just a rather ostentatious wind speed sensor to provide a more accurate assessment of both local wind conditions and the likely visual impact of the prospective purchase of a small 'domestic class' wind turbine.

And for 50% of the time you might only run with one boiler to prevent any idling.

I'm not sure what range of modulation you get for oil fired boilers?

Big old cast iron oil boilers seem to be more reliable than the more modern ones which seem to be forever having electronics failures if my neighbours experiences are anything to go by.

I think you would also have to get special dispensation to fit one that wasn't condensing today. Alter it at all and you are supposed to comply with modern fire safety and bunded oil tank rules too.

Interesting. How do you find having an external boiler? How does the condensate drain avoid freezing when the system is outside?

We may have to go down that route as the position of the old boiler is not suitable for fitting a replacement (basically it was put in place and an extension built around it).

No easy way to install a replacement upstairs without either knocking walls down or dismantling the boiler and reassembling it in situ.

Drivel. Running cost of renewable energy is very low. No cost for primary energy. Low maintenance/attendance costs. Near zero distribution losses.

pinning like a top. Yet only a light breeze... something is not adding up. I reckon it's a fake, and doesn't generate a thing.

You think that because you're stupid. Higher up there is more wind. Some times lots more.

It depends, there are several different principles. The normal domestic ones zero to not much.

I just did and it hasn't changed my mind. Two smaller boilers are not cheaper than one larger one and would require twice the maintenance and (slightly) more complex installation.

True, I just thought it was an interesting story ;-)

Some research and sums will be needed, but I wonder whether it would be better to add a smaller, modern, boiler for periods of light load, and then to bring-in the existing ancient monster when needed. On face value that seems quite attractive because it's then easily DIYable, plus it increases the peak available power.

Hmmm, on further thought, I could use a new boiler to heat the workshop (one of the first projects) and provide the plumbing so that the output can be sent to the house as well - I think that's just one NRV, a couple of lever valves, plus a status light somewhere. Question: for a certain heat output, is a smaller boiler running flat-out more efficient than a large boiler running at a lower load and (probably) cycling?

depends how much cycling is going on.

there is a penalty to starting a boiler in terms of fuel lost

I don't think there is much point in modulating an oil boiler really. They tend to be 'i need heat' 'i dont need heat'

and here it comes:

So long as you ignore the cost of eliminating the intermittency.

What about the gas / coal / oil / diesel they needed to make it useable?

Who are you kidding? You by definition have the starting baseline costs for your backup generation, and then add on those for the renewables on top.

But higher than a conventional power station if its feeding the grid since you are now doing from a wider area (in the case of wind).

And get large subsidies from the taxpayer.