Pre-Heat, does it work ...?

[diamondgas]

Thought it could be interesting to hear your views on the pre-heat function many boilers have. Are you aware of any appliance that benefits from its function? I can't think of any that have overcome the ignition sequence lag between recognising that a demand for hot water has been made to full flame and heating the water in the plate hex!

All the appliances I've experiences offer a nice 'bullet' of hot water then it cools down before returning hot once more!

Is it pointless and a waste of money keeping the plate hex hot?

What ar your thought? Any good experiences?

Steve

 

[quality]

FItting a proper system springs to mind

But my view is pointless purely because I hate combis (with the exception on repairs)

 

[mountainman]

Not a bad idea in theory IMO but I wonder if there is any benefit in the boiler firing up periodically even during the night.
A waste of gas and electric IMO

 

[CES]

Just a nice wee annoyance for the customer when it fires up at 2 am..


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[Destroyer2813]

Just a nice wee annoyance for the customer when it fires up at 2 am..


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And a annoyance for us when people ring up saying there boiler works on its own

 

[diamondgas]

Pre-heat's been around some time, Vokera Linea springs to mind! I just wonder why manufacturers incorporate it when it doesn't seem to work. Ideal still have it on their Logic's I believe! Not sure of any others?

 

[stevetheplumber]

its not a necessesity in this country but invaluble in colder climes where water comes in at much lower temperatures

 

[diamondgas]

its not a necessesity in this country but invaluble in colder climes where water comes in at much lower temperatures

If it worked I'd agree steve but I don't know of any that do! By the time the boiler has lit up the plate hex is filled with cold water so the process of heating up starts at whatever temperature the cold mains is in my experience all it gives the custard is a pint of hot water then back to warming up to temp..! I've measured the cold in this country down to 6[SUP]o[/SUP]C ... That's pretty cold brrrrrrrrrr 🙂

 

[Millsy 82]

If you turn the tap on slowly then it works but if your like me open the tap up straight away it doesnt thats why mine is off on my 831

 

[johnnyplumb]

when i do a new combi swop, one of the things some customers notice afterwards is, the hot water coming through quicker than it did before.

so if there saying this without me prompting them, pre heat must work.

 

[Nostrum]

I think it does work,, but it's not worth the extra running costs

 

[johnnyplumb]

anyone fitted one of these Combisave

i dont know much about them but it might be better than a pre heat

 

[johnnyplumb]

I think it does work,, but it's not worth the extra running costs

worcester has a programmable pre heat so you can set it for peak demand times, still gonna cost you more to run though.

 

[Deleted member 2053]

Definitely in the Logic+ and it works well as the thing lights very quickly. I have come across other boilers where the above-mentioned scenario of hot-cooler-hot again is more typical.

 

[Deleted member 2053]

when i do a new combi swop, one of the things some customers notice afterwards is, the hot water coming through quicker than it did before.

so if there saying this without me prompting them, pre heat must work.

On the other hand it could just be that the higher pressure of a combi is giving a better flow rate than the replaced gravity feed and hence it takes less time to come through.... or ding you mean swapping an old combi with a new combi?

 

[johnnyplumb]

On the other hand it could just be that the higher pressure of a combi is giving a better flow rate than the replaced gravity feed and hence it takes less time to come through.... or ding you mean swapping an old combi with a new combi?

old combi for new combi, is what i mean.

 

[mike_s]

I only set it if the boiler seems a long way from the taps and the customer is concerned about the wait for hot water but I don't reccomend it due to the extra running costs so I hardly ever do.

 

[diamondgas]

anyone fitted one of these Combisave

i dont know much about them but it might be better than a pre heat

It looks like the similar principle a few manufacturers adopted years back with wax capsules inline to reduce the flow until it was actually heated up!

Regards the increase in hot to taps, maybe that's with improved technology reducing lighting up times. Coupled with pre-heat I can perceive it working but you've still got the lag of heating up the primary circuit before the transfer of heat to the plate hex! I don't know if the reduction of time for the water to get hot at the tap is due to the pre-heat. Most likely down to quicker heat transfer times in the main hex to the primaries and faster ignition recognition. Moderd condensing boilers don't have to wait for aps approval?

 

[mfgs]

Pre-heat's been around some time, Vokera Linea springs to mind! I just wonder why manufacturers incorporate it when it doesn't seem to work. Ideal still have it on their Logic's I believe! Not sure of any others?

They do it to meet the water regs, which states you have to be able to get water of 50 degrees at a tap within 30 seconds I think ( could be wrong with the figures ) But that is the reason they have it.