Hot water only works when heating been on

[Daisyiala]

I moved into a house in November and therefore regularly used the heating so didn’t notice this issue. However now that we are in June, we almost never have the heating on, and we are not getting hot water.

We have 2 slides on the thermostat for hot water or heating, we therefore put the hot water on only thinking this was the issue, however this turns the heating on also.

Around 24 hours after the heating has been on we get hot water for a short while. We seem to only get hot water when the heating has been on a day before.

Is this just the type of system we have or is there an issue here?

 

[Scally-Ho]

The 1st problem is you have not given any clues as to what type of boiler you have installed and what type/brand of wall mounted controller you have. The 2nd problem is we need some photos before we can even begin to form an opinion.

 

[CountryFan]

We have 2 slides on the thermostat for hot water or heating, we therefore put the hot water on only thinking this was the issue, however this turns the heating on also.

Are you sure about this? Sounds like a programmer.

Around 24 hours after the heating has been on we get hot water for a short while. We seem to only get hot water when the heating has been on a day before.

As per @Scally-Ho - more information required. Which boiler and or cylinder do you have? S-plan, Y-plan, C planet al?photos would be handy if unsure

Is this just the type of system we have or is there an issue here?

Could be either

 

[Daisyiala]

The 1st problem is you have not given any clues as to what type of boiler you have installed and what type/brand of wall mounted controller you have. The 2nd problem is we need some photos before we can even begin to form an opinion.

Photos attached now thank you

 

[stem]

Usually those symptoms would be where you have a system that has a motorised valve controlling the HW. The HW valve opens, but its internal switch is faulty and it fails to start the boiler. But, when the CH is on, the internal switch inside the CH motorised valve does starts the boiler, and because the HW valve is already open the HW heats up as well.

However, as has been said it depends upon the type of controls you have. The most common systems are either a Y-Plan with a 3-Port Motorised valve or a S-Plan with two or more 2-Port Motorised valves If you can confirm which you have someone should be able to advise you further.

 

[Scally-Ho]

@Daisyiala From the photos we can establish your Vaillant ecoTEC 418 is a system boiler (18kw?) and from the programmer box both hot water and heating should be able to operate independently or both together. What we need now is to establish how the boiler flow is diverted/shared and photographs of motorised valving should help with this task. Motorised valve(s) are usually sited close to the hot water cylinder, so clear close-ups are now needed of your cylinder and its associated pipework