# Boiler query

Found 2nd Feb

I have a system boiler (ideal logic heat 15, 3 years old) and a hot water storage tank in the airing cupboard. I have Hive active heating.

I heat the water for 30 minutes, from 06:00 to 06:30. But, if I try to use the water straightaway at 06:30 once it’s finished heating, it’s not hot enough. Luke warm, but a shower is not pleasant. If it wait another 30 minutes, and shower at 07:00, it’s lovely and hot.

What could be the reason for this? Does the hot water tank further heat the water after the boiler has heated it? I don’t think it’s meant to work like this.
Hot water tank will have a heat exchanger in which is like a pipe through the middle of it which runs hot water through it to heat the water in the tank, from memory a water tank will take around an hour to heat up (hence after an hour it’s hot).
Edited by: "mds1256" 2nd Feb
I’m with you. So... I need to understand this. Currently I set Hive to heat the water from 06:00 to 06:30. I’m finding the water is nice and hot at 07:00. If you’re saying that this is because it takes an hour for the hot water tank to heat up, then why don’t I tell Hive to heat the water, say, for 10 minutes only (saving gas), from 06:00 to 06:10, but still wait until 07:00 to shower. What would be the result then?

Conversely, and purely out of interest, how would things differ if I were, hypothetically, to heat the water for 45 minutes, from 06:00 to 06:45 and still shower at 07:00. What would be the result of this (apart from using more gas)?
Heat it up longer. I set mine to run for 2 hours but thermostat will stop the boiler heating it once at required toasty temperature.
Edited by: "EdinburghShop85" 2nd Feb
Thanks for the replies. The boiler installer told me that 30 minutes would suffice. Clearly that’s wrong. I’ll change it to 60 minutes. So all this time has it been effectively heating for the first 30 minutes using gas (boiler) and the remaining 30 minutes using electricity (water tank)?
Do you have a thermostat on your water tank - something like this?

If so this will control the temperature - allow the boiler to come on "hot water heating" and as soon as the specified temperature is reached this will shut the boiler down.
Van19737 m ago

Do you have a thermostat on your water tank - something like this?[Image] …Do you have a thermostat on your water tank - something like this?[Image] If so this will control the temperature - allow the boiler to come on "hot water heating" and as soon as the specified temperature is reached this will shut the boiler down.

I do, yes, exactly like that. But I don’t understand. Regardless of what I set that to, it’s not going to heat unless I also set the hot water to heat (gas boiler on) in Hive...right?
Rastafari3 m ago

I do, yes, exactly like that. But I don’t understand. Regardless of what I …I do, yes, exactly like that. But I don’t understand. Regardless of what I set that to, it’s not going to heat unless I also set the hot water to heat (gas boiler on) in Hive...right?

Rastafari3 m ago

I do, yes, exactly like that. But I don’t understand. Regardless of what I …I do, yes, exactly like that. But I don’t understand. Regardless of what I set that to, it’s not going to heat unless I also set the hot water to heat (gas boiler on) in Hive...right?

That's right.

The water will only be heated if...... (1) the Hive is set to Hot Water ON and (2) the temperature in the cylinder is below the specified temperature of the thermostat (most people set that at 60°C).

So it will stop heating either (1) the Hive switches the Hot Water Heating to OFF or (2) the water heats up to the set temperature.
You will need to keep the boiler heating the water for the water to get hot.... not sure of the question here now as you have already worked out the solution. If you want the water hot for 6:30am then set the timer to start heating the water at 5:30am.......
Rastafari1 h, 19 m ago

Thanks for the replies. The boiler installer told me that 30 minutes would …Thanks for the replies. The boiler installer told me that 30 minutes would suffice. Clearly that’s wrong. I’ll change it to 60 minutes. So all this time has it been effectively heating for the first 30 minutes using gas (boiler) and the remaining 30 minutes using electricity (water tank)?

The hot water tank doesn't heat the water up unless you have an immersion heater which is electric and you've turned it on (I wouldn't recommend using the immersion, very expensive to run). So turning your boiler on for longer and following the above on hive needing to be on, and thermostat set to desired temp will do the trick.
Thanks, everybody.
Sorry, one question still remains.. if Hive has been telling the boiler to heat the water for 30 minutes, but it doesn’t actually get hot enough until after one hour has passed, how has the water been getting hot during the second half hour while the boiler was off?

Because..

mds12561 h, 34 m ago

You will need to keep the boiler heating the water for the water to get …You will need to keep the boiler heating the water for the water to get hot...

EdinburghShop8555 m ago

The hot water tank doesn't heat the water up unless you have an immersion …The hot water tank doesn't heat the water up unless you have an immersion heater which is electric and you've turned it on

There is an immersion heater but I never turn it on.

i just don’t seem to be able to grasp why the boiler has been heating the water for 30 minutes but it needs a further 30 minutes of the boiler not heating the water in order for it to get hot.
Rastafari50 m ago

Sorry, one question still remains.. if Hive has been telling the boiler to …Sorry, one question still remains.. if Hive has been telling the boiler to heat the water for 30 minutes, but it doesn’t actually get hot enough until after one hour has passed, how has the water been getting hot during the second half hour while the boiler was off? Because..There is an immersion heater but I never turn it on.i just don’t seem to be able to grasp why the boiler has been heating the water for 30 minutes but it needs a further 30 minutes of the boiler not heating the water in order for it to get hot.

because there is still a lot of heat in the heat exchanger and the circuit going thru the heat exchanger? sounds like the answer but it seems an inefficient method maybe ask the plumber again
Is your central heating on after your hot water goes off (during the 30 min period between when your hot water goes off and you take a shower)? The valve could be passing to the hot water circuit

because there is still a lot of heat in the heat exchanger and the circuit …because there is still a lot of heat in the heat exchanger and the circuit going thru the heat exchanger? sounds like the answer but it seems an inefficient method maybe ask the plumber again

I guess it could be this.
richy_ctr5 h, 50 m ago

Is your central heating on after your hot water goes off (during the 30 …Is your central heating on after your hot water goes off (during the 30 min period between when your hot water goes off and you take a shower)? The valve could be passing to the hot water circuit

Yes, so I guess it could be this also / instead.

I need to get the boiler serviced soon so I’ll ask plumber about this phenomenon while he’s here. He’s partial to my bean-to-cup coffee. Nice guy.
Rastafari22 m ago

I guess it could be this. Yes, so I guess it could be this also / …I guess it could be this. Yes, so I guess it could be this also / instead.I need to get the boiler serviced soon so I’ll ask plumber about this phenomenon while he’s here. He’s partial to my bean-to-cup coffee. Nice guy.

i was going to try this on mine but then found out it had broken down :O