Water flow temperature

[iMCaan]

Hi

 

I've noticed our boiler is continuously showing water flow temperature of ~64c whether we are using water or not. Shouldn't the flow temperature on the boiler drop down to around 20c when the water temperature in the cylinder reaches it's set temp? You can hear the boiler  coming on and going off but the flow temp, though it drops by a few degrees when boiler is off, it remains around 60c.

 

The flow and return pipes to the cylinder are hot to touch. The cold feed is also hot to touch but less hot then flow and return. Shouldn't the cold feed be cold?

 

I got to say, the garage where the boiler is located is warmer then other rooms. 

 

Thanks 

[SteamyTea]

No idea about your make of boiler, but a friend of mine had a high gas bill, @Nickfromwales knew the type of boiler and said that as it has a small internal cylinder, this was being kept up to temperature.  He told me what to change to turn the feature off.  It did reduce the gas bill.

Maybe yours is the same.

[Nickfromwales]

Ok, is this a system or combi boiler? You say cylinder so assume there’s an unvented hot water cylinder?

 

If its in the garage, make an insulated boiler cupboard and reduce your latent losses by a fair bit (sounds expensive if you’re heating a cold ventilated garage!).  
 

Need as much info as possible, and a picture of all plumbing and the cylinder plz. 

[John Carroll]

If its a combi Vaillant and has a HW store, it will begin with a "9", a standard Combi begins with a "8", a non combi system boiler begins with a "6" and a heat only boiler with a external circ pump begins with a "4".

[Nickfromwales]

12 hours ago, SteamyTea said:

No idea about your make of boiler, but a friend of mine had a high gas bill, @Nickfromwales knew the type of boiler and said that as it has a small internal cylinder, this was being kept up to temperature.  He told me what to change to turn the feature off.  It did reduce the gas bill.

Maybe yours is the same.

Some have a cylinder (or store) but others simply don't let the plate heat exchanger go cold, and just pass heated water through it; no stored water as such, just far less delay getting premium temp DHW from device > outlet. 

[iMCaan]

Thank you for the replies. Apologies for late reply.

 

It's a Vaillant ecoTec Plus 635 system boiler. I've attached a photo of the system. It's a few months old but nothing has changed.

 

@SteamyTea thanks. Will see if I can find similar settings on my boiler.

 

@Nickfromwales thanks. I don't think there will be enough space left for the car if fit an insulated boiler cupboard.

 

 

 

 

[John Carroll]

IF you programme the hot water Off does the boiler still continue firing intermittently?, if it doesn't then you may have a faulty cylinder stat or you may have a zone valve end switch not opening even though the vale is closing, the boiler will then keep firing, controlled by its own boiler stat.

[iMCaan]

Thanks @John CarrollI will test that tomorrow evening.

As we have not yet moved in, I turned the hot water off earlier and the boiler went off It didn't turn back on while it was off from the programmer. The flow rate started to go down.

I will do some more testing tomorrow.