Boiler "on" times

[Eamonn]

Hi

I have just had my oil certikin boiler serviced and begun to heat my freezing 15 degree cold water up for the first time (in my ownership)...what I don't get is the boiler only stays on for 5 minutes then cuts out for about 7 minutes...then comes back on again for another 5 minutes...the boiler guy tells me this is normal as it is a gradual process that will take up to 4 days to heat the pool....I cant understand why the boiler cant stay on all the time though until it gets to the required temp ??? he mentioned something about the plastic pipe work not being able to take high heat and this is how swimming pools work ??? anyone know if this is correct or just BS ?..

[Glan]

Hi Eamonn,
As you suspected, it is total BS…………
The reason your Certikin Oil boiler cycles on and off, is that it works in an indirect way. That is it heats up a sealed central heating loop of water, which like your household central heating, is then pumped around the heat exchanger within the boilers case by a small Grundfos pump. Your swimming pool water is also pump around this same heat exchanger by your pool pump, as the two waters meet across the stainless steel heat exchanger, the hotter boiler water warms the stainless, the cooler pool water nicks all the heat it can from the stainless heat exchanger, and so the boiler hot water cools. To maintain the boilers internal water temp, the boiler fires up from time to time to keep the central heating water hot.

On the front of your boiler you have 2 temp gauges, the first is your pool water temp, the second is the internal boiler water temp, just the same as if you turned your household boiler up to max on the dial, all this does is increase the internal water temperature, obviously the hotter the internal water temp, the quicker the pool water will heat up.

Hope this covers the BS element.

ATB

Glan

[Eamonn]

Hi Eamonn,
As you suspected, it is total BS…………
The reason your Certikin Oil boiler cycles on and off, is that it works in an indirect way. That is it heats up a sealed central heating loop of water, which like your household central heating, is then pumped around the heat exchanger within the boilers case by a small Grundfos pump. Your swimming pool water is also pump around this same heat exchanger by your pool pump, as the two waters meet across the stainless steel heat exchanger, the hotter boiler water warms the stainless, the cooler pool water nicks all the heat it can from the stainless heat exchanger, and so the boiler hot water cools. To maintain the boilers internal water temp, the boiler fires up from time to time to keep the central heating water hot.

On the front of your boiler you have 2 temp gauges, the first is your pool water temp, the second is the internal boiler water temp, just the same as if you turned your household boiler up to max on the dial, all this does is increase the internal water temperature, obviously the hotter the internal water temp, the quicker the pool water will heat up.

Hope this covers the BS element.

ATB

Glan

Thanks for the great explanation which makes perfect sense....the temp has gone from 15 to 22 degrees C in about 12 hours so it certainly seems I am starting to get somewhere at long last...any idea how hot it would be in the 4 days the boiler guy has estimated (no cover and with our current fairly warm ambient temps) ???