What does the symbol mean on boiler DHW

[BobbyJoe]

Hi I bought a Vokera Combi Boiler last year (Vokera Easi-heat plus 25c) and am looking for advice on one of the symbols on the DHW dial.

On the DHW temperature dial after the tenth dot (going clockwise) their is a small green tap symbol with a little Z under it, what does that symbol mean and is it safe to turn the dial to that symbol for the hot water?
I took the temperature when I turned the dial to that little tap z symbol and it was at 55 degrees Celsius. Could it be the Eco or pre-heat function?
The flexi pipes were roasting when I touched them and I am wondering if it is okay to keep the dial on that symbol and if the flexi pipes which are a year old will be able to handle the heat?

Any information would be great thank you as the boiler manual didn't answer the above question and I thought to ask the experts.

 

[ShaunCorbs]

Any chance of a pic of the pipes ?

 

[Gasmk1]

https://www.vokeraeasiheat.co.uk/brochure/usersInstructions.pdf. If you read the user section it’s the hot water pre heat function

 

[BobbyJoe]

Thank you very much for the reply as the Vokera brochure states "Turning the domestic hot water temperature adjustment knob to the symbol activates the pre-heating function. This function keeps the water in the domestic hot water exchanger hot, to reduce standby times when a request is made."

So my next question is it okay to just leave my DHW on the pre-heat setting, will it make the boiler overheat or anything or is it perfectly safe?

The hot water does get very hot 55 degrees Celsius without mixing any cold water when on pre-heat but I like the fact that as soon as I run the hot water tap I don't need to wait for the water to warm up.

Any advice would be great thanks

 

[Gasmk1]

no you turn pre heat on then put dial back to where you require if you read the instructions then you will know

 

[BobbyJoe]

The pre-heat dial function is on the same DHW temp dial, so I have to turn it all the way round and leave it at that.

 

[Basher]

The pre-heat dial function is on the same DHW temp dial, so I have to turn it all the way round and leave it at that.

As Gasmk1 says, the instructions describe how you turn the knob round to the pre-heat position, which activates the function and the yellow led comes on. You are then supposed to immediately turn the knob back to the temperature you want the water.
When you want to turn pre-heat off, you turn the knob again to the pre-heat position, the yellow light goes out and the function is disabled. You then return the knob to the water temperature you require.

I don't think it is intended that you leave the knob in the pre-heat position. That's presumably why the water is so hot!

If your boiler doesn't work like that, maybe I am looking at the wrong instructions!

 

[BobbyJoe]

Oh thank you I got it now as I had no idea what to do when the yellow light came on and left the dial on the pre-heat symbol which might explain why the DHW was roasting and the flexi tails were too hot to touch!
It makes sense now thanks again

 

[Ric2013]

Water Regs question directed at other plumbers:

If the pre-heat function is storing the water at a temperature, then should the OP not be setting that temperature to be 60°C (or as close as possible) rather than turning the setting down?

 

[SimonG]

Water Regs question directed at other plumbers:

If the pre-heat function is storing the water at a temperature, then should the OP not be setting that temperature to be 60°C (or as close as possible) rather than turning the setting down?

It's not storing hot water, its flushing central heating water through the plate heat exchanger to keep it warm to react quicker when a tap is opened.

 

[rpm]

Hiya BJ, has that horrid LL given you a new boiler then and whilst here how is that skin rash of yours, all cleared up after 4yrs I hope.

 

[Ric2013]

It's not storing hot water, its flushing central heating water through the plate heat exchanger to keep it warm to react quicker when a tap is opened.

Thanks for that. I'd always assumed the pre-heat function meant there was a small thermal store built into the boiler. Good to have learnt something!