Boiler/emersion question

[stender]

HI All, In my old house (3bed) I replaced a boiler and boiler mate with a combi. Worked great for heating and bath/showers. Now moved into an extended 4 bed. We have a combi boiler in the extension but also have an emersion heater and pump in airing cupboard in the house and water tank in loft.
Can anyone advise why I need an emersion and water tank when i didn't in my old house? we tried turning the emersion off but seemed to get no hot water when having a shower or even at kitchen sink. Yes my house is larger but seems odd to me having both.

Thanks

 

[ianmcd]

Does the programmer for the combi have a HW on/off switch on it ?

 

[stender]

Hi, The programmer is in the airing cupboard next to emersion but yes it does have HW on off i believe. The combi boiler has a hot water dial on it. Vailant eco combi

 

[ianmcd]

sounds like you have a combi boiler AND a hw cylinder that is also heat by the combi with an immersion back up, quite common to do this in larger properties, can you see any three port or two port valves anywhere, posting a pic of your HW cyl set up would help

 

[stender]

will do. thanks

 

[gasbanni]

A few good pictures of the hot water cylinder installation will help to see what you've got .....and your combi controls !

 

[MeldrewsMate]

You may find that the combi only feeds one or two hot water outlets, its central heating output is used (as on a standard boiler setup) to heat up a hot water cylinder, and this cylinder will feed baths and showers, etc. Often a tank fed hot water system will outperform a combi when it comes to feeding two outlet concurrently, and nearly always will fill a bath quicker.
It's a strange phenomenon, but the combi version of a boiler is usually a lot cheaper than the sealed system version, even though the combi has more parts to it!

Try turning off the combi, then run each hot tap in turn...the ones that run hot will be tank fed.

MM

 

[stender]

Not sure if these are any use but this is the airing cupboard. Have some pipes to loft and some downstairs.

 

[ianmcd]

You do indeed have an indirect HW Cylinder , this will be served by the Combi boiler and the immersion heater is just a back up, you have a control fault somewhere, most commonly a zone valve

 

[stender]

Sorry what does that mean? Ihave valves in the airing cupboard and valves by the combi.

 

[ianmcd]

The silver box next to your cylinder is a three port valve, it directs water from the combi to heat the HW or the CH or both at the same time, depending on what has been selected, there is either a fault with that or the small grey thermostat on the cylinder itself, you also have a gate valve (manual valve with round red handle) on the flow to the indirect coil, make sure that has not been closed by mistake, for future reference your system is a fully pumped Y plan with Immersion back up

 

[stender]

Thanks. What would the fault be doing? Are you saying if it weren't for the fault I could turn off the emersion and all hot water would come from the combi? Why would they keep the emersion if the combi can service the house? surely it's more cost effective to just use the combi?

 

[ianmcd]

Thanks. What would the fault be doing? Are you saying if it weren't for the fault I could turn off the emersion and all hot water would come from the combi? Why would they keep the emersion if the combi can service the house? surely it's more cost effective to just use the combi?

yes the immersion is only for emergency back up to give you HW in the event that your combi boiler faults

 

[wannocks]

Hi, The programmer is in the airing cupboard next to emersion but yes it does have HW on off i believe. The combi boiler has a hot water dial on it. Vailant eco combi

What numbers are next to the model name on your boiler? It may not be a combi. Probably an Ecotec plus or an Ecomax. If it starts with an 8 its a combi, if it starts with a 4 or 6 it isnt. Having a HW knob doesn't mean it's a combi.
(There's no such thing as a Vaillant Eco combi!)

 

[stender]

I'll have to dig out the paperwork. It just says eco compact valiant. It looks to be the same or very similar to the combi I had in my old house with no emersion. But they all look the same to most of us.