Boiler Replacement

[jj4091]

After another breakdown I have decided it might be time to replace our 16 year old Ideal Logic 35.
In order to get an idea of the costs I tried a couple of these online pricing sites.
They ask various questions but one that I would like some help on is the number of radiators. Do double radiators count as a single radiator or two for the purpose of assessing the correct boiler size. Thanks

 

[denso13]

Just one, it is only an indication of what size boiler is required, it isn't exact.

 

[gas112]

replace it for another logic be a doddle of a job as all pipes and flue hole should line up saving you labour costs
Get someone local through recommendation from family /friends

 

[muggles]

A proper heat loss calculation determines the correct boiler size, and that can only be done with a site visit. Assuming you're in England or Wales, it's been part of Building Regulations to do this for a boiler replacement. The online sites won't care whether it's a single or double, they'll be taking a finger in the wind average, making assumptions that you will have some of each

 

[gas112]

A proper heat loss calculation determines the correct boiler size, and that can only be done with a site visit. Assuming you're in England or Wales, it's been part of Building Regulations to do this for a boiler replacement. The online sites won't care whether it's a single or double, they'll be taking a finger in the wind average, making assumptions that you will have some of each

LOGIC 35 so a combi so will be sized for HW on a like for like 35 it drops down to 7.5kw the 30 drops to 6.4kw

 

[fixitflav]

After another breakdown I have decided it might be time to replace our 16 year old Ideal Logic 35.
In order to get an idea of the costs I tried a couple of these online pricing sites.
They ask various questions but one that I would like some help on is the number of radiators. Do double radiators count as a single radiator or two for the purpose of assessing the correct boiler size. Thanks

Is there any reason to think a replacement with similar output to the existing wouldn't be OK?

 

[kidgreen61]

New build house builders love throwing in Logic ESP 35 boilers, they must get them dirt cheap from Ideal.
Half the time, they're grossly overpowered for the house.

 

[jj4091]

Is there any reason to think a replacement with similar output to the existing wouldn't be OK?

When the boiler was installed we had a large cast iron roll top bath that took too long to fill from the boiler that was in when we bought the property. The Logic 35 gave 17L/Min and was much quicker for running a bath. I always felt it was a bit overpowered but wanted the convenience. I will get proper size calculations done before I order the replacement.The online pring sites suggested that 30KW boiler would be adequate but I wasn't sure if the majority of the radiators being doubles would make a different result

 

[gas112]

When the boiler was installed we had a large cast iron roll top bath that took too long to fill from the boiler that was in when we bought the property. The Logic 35 gave 17L/Min and was much quicker for running a bath. I always felt it was a bit overpowered but wanted the convenience. I will get proper size calculations done before I order the replacement.The online pring sites suggested that 30KW boiler would be adequate but I wasn't sure if the majority of the radiators being doubles would make a different result

ideal logic 30kw will give you about 12.4 litres per minute a 24 will give you 9.9 litres the 35 gives 14.5 litres
Hw delivery is your first consideration when going for a combi

 

[vulcancontinental]

A three bedroom semi built in the 30's with solid walls, double glazing throughout, 200mm insulation in the loft and an uninsulated suspended ground floor is likely to have a heating loss of around 8kW at -3°C so your concern with heating is how low can the boiler go not how high. The higher power is for hot water flow (if you have a main that can deliver an appropriate supply of cold water).

A boiler that modulates to below 3kW, preferably 2kW would be suited well as the weather is rarely -3°C, more likely 6-10°C so the boiler that can't modulate below 6kW will be cycling a lot.

 

[jj4091]

ideal logic 30kw will give you about 12.4 litres per minute a 24 will give you 9.9 litres the 35 gives 14.5 litres
Hw delivery is your first consideration when going for a combi

Now I only have a shower I assume 12.4 litres/min would be ample, as they claim it will be for a shower.

 

[jj4091]

A three bedroom semi built in the 30's with solid walls, double glazing throughout, 200mm insulation in the loft and an uninsulated suspended ground floor is likely to have a heating loss of around 8kW at -3°C so your concern with heating is how low can the boiler go not how high. The higher power is for hot water flow (if you have a main that can deliver an appropriate supply of cold water).

A boiler that modulates to below 3kW, preferably 2kW would be suited well as the weather is rarely -3°C, more likely 6-10°C so the boiler that can't modulate below 6kW will be cycling a lot.

That pretty much describes our house except that we have uninsulated cavity walls so I guess the heat loss would be similar. Would you know or can you tell me how to find out the figures for modulation for a 30KW Ideal boiler.

 

[gas112]

Now I only have a shower I assume 12.4 litres/min would be ample, as they claim it will be for a shower.

yeah that will be plenty for the shower

 

[denso13]

Would you know or can you tell me how to find out the figures for modulation for a 30KW Ideal boiler.

It'll go down to just over 6kw, others go lower.

 

[gas112]

That pretty much describes our house except that we have uninsulated cavity walls so I guess the heat loss would be similar. Would you know or can you tell me how to find out the figures for modulation for a 30KW Ideal boiler.

i gave the figure for the 30kw on post 5