Most efficient setting for my logic s30 system boiler?

[Husk24]

Hi

I have a Ideal Logic S30 System Boiler, and I have always left it on eco setting which is 70 degrees. I have a separate thermostat for my water tank set at 65.

I don’t understand the condensing part of the boiler but I believe there is the most efficient settings you can have for this boiler, is 70 degrees the correct /most efficient settings for this boiler?

Thanks
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[Chuck]

I'd try reducing the water tank thermostat to 60°C and the boiler flow temperature to 65°C.

There is a range of opinions on this point but, IMO, if you want to reduce the DHW below 60°C you need a weekly higher-temperature disinfection cycle, which is a bit of a nuisance if your system can't do it for you automatically.

The Ideal Logic S30 System Boiler manual says:

"The boiler controls the central heating radiator temperature to a maximum of 80°C, adjustable via the CH temperature control (A). The Logic System is a high efficiency condensing boiler which is most efficient when operating in condensing mode. The boiler will operate in this mode if the CH temperature control (A) is set to the ‘e’ position (economy mode). This control should be set to maximum for very cold periods"

I suspect that in reality the 'eco' position (ca 70°C flow) is maximum for which you might benefit from condensing (i.e. 70/50) but that requires an emitter system with deltaC = 20°C, which is a bit optimistic IME.

 

[Husk24]

Great, I will reduce it to 65, but will this not make my boiler stay on for longer to heat the rooms?

 

[Chuck]

Great, I will reduce it to 65, but will this not make my boiler stay on for longer to heat the rooms?

In principle, yes but the lower operating temperature will make the boiler work more efficiently giving an overall net saving.

You do, however, need to reduce the temperature of the hot water tank thermostat to 60°C because it needs to be 5°C lower than the boiler temperature in order to heat the tank efficiently.

 

[Husk24]

In principle, yes but the lower operating temperature will make the boiler work more efficiently giving an overall net saving.

You do, however, need to reduce the temperature of the hot water tank thermostat to 60°C because it needs to be 5°C lower than the boiler temperature in order to heat the tank efficiently.

Thanks, I have done that, boiler to 65, tank to 60.

I have the water heating on a timer, 30 mins morning, 30 mins midday and 30 mins evening during winter (for spring summer I have solar thermal).

Would you say this is the most efficient way to heat the water?

 

[Chuck]

I have the water heating on a timer, 30 mins morning, 30 mins midday and 30 mins evening during winter (for spring summer I have solar thermal).

Would you say this is the most efficient way to heat the water?

No. Assuming the tank is well-insulated I'd start with heating it for 90 minutes in the morning say from 0530-0700, i.e. just before the central heating comes on at 0700. This is because the tank-heating process gets less efficient as the store temperature approaches the 60°C set point.

Add a mid-afternoon boost if you find you've run out of hot water by the evening.

Frankly, the difference made by tuning the heating schedule is going to be relatively small. By far the best way to save money on heating hot water is to use less of it. You not only save on heating but also on the water bill. (I'm big a fan of Mira 'eco' shower heads.)

 

[Husk24]

No. Assuming the tank is well-insulated I'd start with heating it for 90 minutes in the morning say from 0530-0700, i.e. just before the central heating comes on at 0700. This is because the tank-heating process gets less efficient as the store temperature approaches the 60°C set point.

Add a mid-afternoon boost if you find you've run out of hot water by the evening.

Frankly, the difference made by tuning the heating schedule is going to be relatively small. By far the best way to save money on heating hot water is to use less of it. You not only save on heating but also on the water bill. (I'm big a fan of Mira 'eco' shower heads.)

My water tank is new pictured in my profile ,I installed it last year with solar thermal, the one little mistake I made was I replaced it from 200 litres to 300 but probably didn’t really need that capacity so i guess i have more heat loss with a bigger tank and obviously takes longer to heat.

A few queries with your suggestion, If my tank reaches 60 degrees before 90 mins then the boiler would switch off wouldn’t it? I guess I need to try it out but will it stay hot for for the rest of the day/evening and if I do need to boost it wouldn’t that use more energy compared to the way i am heating up currently?

Can you explain how would it be beneficial for me to heat it the way you suggested?

What do you mean by the tank heating process gets less efficient as the store temperature approaches 60 degrees.

We don’t have the central heating on overnight and usually turn it on from 10.30am in morning till evening.

Many thanks for your suggestions.