Hot water questions

[Nickclarke2183]

Hi

So recently moved into a new house (new for us not new build) and it's a totally different system to what we have had in past houses so trying to get to grips with it.

I know it's a gravity fed system with a system boiler (not combi).We have a large cold water tank in the loft with a smaller feeder? Tank next to it. We also have a hot water tank in the airing cupboard.

Heating all works fine but struggling to get to grips with the hot water an optimising the setup. We have a nest thermostat so looking to optimise the hot water schedule via the boiler rather than electric immersion heater.

I currently have the boiler to schedule hot water in the morning and evening for an hour at each time. However the water never seems to last past a single shower or even to midday if we don't have a shower.

This doesn't seem quite right as I would have thought even with the immersion off then the insulation should keep the water hot for longer.

The tank also has an actuator, whatever that is set to H.

Any advice please?

 

[muggles]

Some photos of your setup would help, but in the meantime...
What is your cylinder thermostat set to?
Is there any appreciable difference in performance if you heat the water for 2 hours in the morning instead of one?
What area of the country are you in (nearest town)?
How old do you think the system is?

 

[Nickclarke2183]

Attached a photo.

Cylinder is set to 60. No difference in performance if i change the length of time the boiler is on for.

Southampton.

We think maybe 10years tops..... Serviced Feb.

 

[ianmcd]

The tank also has an actuator, whatever that is set to H.

post a pic of this please

 

[Nickclarke2183]

Actuator photo attached

 

[CBW]

Select hot water only on your programmer and then go back to this actuator and see if the black slider moves, and tell us where it moves to.

 

[ScottishGasMan]

As above, turn hot water on, on its own and tell us where the actuator is.

What boiler do you have?

Chances are its just an old type of cylinder and old system that will need to be on longer than an hour each time to heat it properly (also could do with a photo of boiler front to see what temp the thermostat there is set to)

 

[Nickclarke2183]

It's a valliant boiler.

The slider on the actuator does move when the hot water switches on.

Boiler can only set one temp for both hot water and rads.... 65 currently.

 

[ScottishGasMan]

If the heating seems a good temp for you, then its more than likely that you just need the hot water heating for longer to get it up to temperature, a cylinder like that probably doesn't have a high recovery coil so regardless of size and power output of boiler the cylinder can only transfer a small amount of that to heat the stored water.

Have it on 3 hours morning, 3 hours night, and if its ok then possibly try reduce the times bit by bit to make it as economical as possible, make sure if your control allows it that you set the Hot water heat up times outside of the space heating times, ie if your heating is timed to come on at 8, have your hot water timed for 6.

The lagging on those cylinders will help a lot compared to old bare copper cylinders, but not be anything like the efficiency of what you see on modern unvented cylinders so reheating in the PM even if you haven't run any water off will likely be necessary

If after having it on for decent times its not hot enough or running out quick, then there may be a blockage or other reason for the cylinder not heating correctly to begin with needing investigated

 

[CBW]

The slider on the actuator does move when the hot water switches on.

.

But where to? Feel the pipes leading to cylinder to determine if hot or warm, if hot then as per @ScottishGasMan states it’s just finding that balance. If warm then water isn’t diverting correctly.