Baxi Combi Instant 80 HE Preheat function

[Pacm0n]

Hi,

After a bit of advice please.

i've just moved house and in the property is a Baxi Combi Instant 80 HE.

Now there is the hot water pre heat dial. Is it more economical to keep the water heated or to switch the dial completely off and just let the boiler heat water when demanded?

The reason I ask is because I can hear the boiler firing up every now and then heating the stored water surely this is less economical as it is keeping the water heated 24/7?

Please let me know you thoughts, thanks.

 

[plumbplumb]

Leaving the preheat function on uses more energy both gas and electric as the boiler fires in order to maintain it's heat.

If you have short runs of pipe then it really isn't required however with long runs you may be drawing off more water in order to get the boiler up to temperature. If you can live with that then I'd switch it off

 

[Terry7556]

ive got a nephew with this boiler and we are dis ableing the pre heat by removing the jumpers off the pcb.
i met a baxi trainer last week and his opinion was if you could live with the noise the preheat was more economical, when you ran a tap , with the water already heated then the boiler does,nt need to run at full bore. not sure about that.
i meant about the noise of the boiler during the night when you are trying to sleep, the nephews boiler is in the bathroom next to their bedroom

 

[Pacm0n]

Terence,

The boiler wakes me up every now and then when the pre heat is on as the boiler is directly below my bedroom. I've switched it off tonight and will see how I get on. Out of interest why do you need to remove the breakers from the PCB? The manual says to turn the preheat function off just turn the dial to the off position, it still heats water but only when demanded.

 

[Pacm0n]

Apologies you didn't say breakers..... I meant jumpers, lol

 

[Terry7556]

i did,nt realisle that and i have a copy of the manual for him , shows how much attention i pay.
do you have an external expansion vessel? ours has gone on the original, so its an external one.
didnt see you were from derby till now, i just bought a pump for him from ebay off a lovely couple in alvaston. i can stop his pump with a screwdriver in the opening when you remove the bleed screw

 

[gazthepottertonengineer]

Terence,

The boiler wakes me up every now and then when the pre heat is on as the boiler is directly below my bedroom. I've switched it off tonight and will see how I get on. Out of interest why do you need to remove the breakers from the PCB? The manual says to turn the preheat function off just turn the dial to the off position, it still heats water but only when demanded.

The problem with turning the dial down is you also put the hot water temperature at the minimum setting! If you remove the jumper you can still set the hot water a decent temperature!

 

[Terry7556]

thats what i was told by mr. lovegroove at warwick last wed on a wiring course.
i went there today to my nephews house and tried the water on the preheat off setting and the water never went above 30/40 degrees, so i think ill be checking out a10 and a11

 

[Pacm0n]

Terence,

The boiler wakes me up every now and then when the pre heat is on as the boiler is directly below my bedroom. I've switched it off tonight and will see how I get on. Out of interest why do you need to remove the breakers from the PCB? The manual says to turn the preheat function off just turn the dial to the off position, it still heats water but only when demanded.

The problem with turning the dial down is you also put the hot water temperature at the minimum setting! If you remove the jumper you can still set the hot water a decent temperature!

Is that 100% right? I've had the dial down to "0" for 3 days now and I still get red hot water after 1 minute or so without the preheat on. It's warm after about 10 - 30 seconds?

 

[Terry7556]

im not 100% sure myself but folks have different reasons for doing things, my nephew and his wife work so the preheat wastes gas/money heating water when they are not there to use and there is the noise element as well at night