Setting Flow Temp on System

[uncleg]

I had another topic asking how to get the best use of mu system which uses the eco tec plus valiant boiler and unistor.

A gentleman posted that "If your system is set up correctly then you should have a temperature difference on the flow and return pipes to your boiler of 20ºC, with a flow temperature of about 60ºC, this will keep your boiler in condensing mode for longer and lower your gas bills as a result"

By the pipes in the garage near the cylinder are two grey boxes with something about temperature written on them - are these them? They are both set to Auto and not manual, plus I can not see how I would change the temperature (gueess I would open them up). am I right?

If so, I am not sure I would know which does what? system was inherited, can someone please help?

Thanks

 

[D_Hailsham]

By the pipes in the garage near the cylinder are two grey boxes with something about temperature written on them - are these them? They are both set to Auto and not manual, plus I can not see how I would change the temperature (gueess I would open them up). am I right?

Do the boxes look like this?

View media item 11762

 

[uncleg]

By the pipes in the garage near the cylinder are two grey boxes with something about temperature written on them - are these them? They are both set to Auto and not manual, plus I can not see how I would change the temperature (gueess I would open them up). am I right?

Do the boxes look like this?

View media item 11762

Yep thats them, with the level on the side saying Auto or Man...

Thanks

 

[D_Hailsham]

Yep thats them, with the level on the side saying Auto or Man...

Thought so

Those are motorized valves, the box on the top contains the motor and other bits. They open and close under the control of the room and cylinder thermostats to let water circulate through the radiators or hot water cylinder.

They have nothing to do with boiler temperature. Leave them alone!

As for the advice to have the flow temp at 60C with a differential of 20C, you can only do that if your complete system has been designed with that in mind. This means installing oversized radiators.

If this has not been done, I would leave the boiler temperature as it is.

Note

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[uncleg]

thanks for your reply and advice.

To summarise, the water temp on the bolier can be turned right down as the temp setting on the unisotr (65c) controls this?

The temp dial for the radiators on the bolier purely heat the water which is sent to the rads, so to save money I shld not have this that high, if the rads by touching are hot enough?

Thanks

 

[D_Hailsham]

What controls do you have? e.g VR65 etc, room thermostat, cylinder thermostat etc.

To summarise, the water temp on the boiler can be turned right down as the temp setting on the unistor (65c) controls this?

No. The water in the Unistor is heated by water from the boiler circulating though a coil in the Unistor. So the temperature on the boiler must be higher than the Unistor or the water will not be heated.

The temp dial for the radiators on the boiler purely heat the water which is sent to the rads, so to save money I should not have this that high, if the rads by touching are hot enough?

What temp dial? Are you talking about a thermostat on the wall in the hall/living room or a dial on the boiler?

The same water goes through the radiator and the Unistor.

 

[uncleg]

Hi,

I have the eco tec plus boiler and unistor cyclinder. Hallway has a room thermostat and most rads have trv's.

My initial question is to check that I am using this how I should be.

water: - temp is set on the unistor currently at 65c - question is that on the bolier there is a gauge for water, so what does this control do? and what should be set to? goes from 6 o'clock position as low and clockwise. Currently set at 9 o'clock which I can not until i go home, recall what temp this represents

Radiator - bolier also has another dial which you can turn and again this relates to temperature settings, my question is that what does this control? assuming how hot your rads are?

I understand that the room thermostat will determine how warm it is and will cut off the boiler if it reaches this. Just that at 20c, bolier never goes off, so assuming the hallway never gets this hot (could be due to insulation etc).

Thanks very much, just trying to use the system correctly and efficiently.

Thanks

 

[D_Hailsham]

water: - temp is set on the unistor currently at 65c

Too high. Set it to 60°C

May be able to answer your other questions when you tell me which model Ecotec plus do you have.

 

[uncleg]

thanks will cahnge the setting.

I have a uniSTOR 260 and the eco tec plus is a 637.

Many thanks for your assistance.

 

[D_Hailsham]

on the bolier there is a gauge for water, so what does this control do? and what should be set to? goes from 6 o'clock position as low and clockwise. Currently set at 9 o'clock which I can not until i go home, recall what temp this represents

What gauge are you talking about? Is it the one in the bottom right of the control panel next to the on/off switch? If so that's the pressure gauge. The needle should be in the grey area when the system is cold.

Or are you talking about the two rotary knobs, one above the other, on the left of the control panel? These are temperature controls.

The top knob sets hot water temperature on combi boilers, it does nothing on system boilers like yours.

Radiator - boiler also has another dial which you can turn and again this relates to temperature settings, my question is that what does this control?

The bottom knob controls the temperature of water circulating thorough the radiators and the heating coil in the unistor. Vaillant recommend the following settings:

– Left setting (9 o'clock) during spring and autumn,
– Middle setting (12 o'clock) during mild winter,
– Right setting (3 o'clock) during cold winter.


PS If you don't have the user instruction book, it's Here.

 

[gas4you]

You haven't clearly answered the previous question as to whether you have a VR65 fitted.

If you have then the top stat dial will control the HW in the unistor if you want. Also if you do and have the unistor ntc fitted, you can run the boiler stat at 60c and the VR65 will boost this when the unistor demands heat.

If not, I would always set the boiler stat to 5 degrees above the unistor set temperature, eg 65c.

 

[D_Hailsham]

You haven't clearly answered the previous question as to whether you have a VR65 fitted.

Well spotted. I assumed he did not have one.

 

[uncleg]

Thank you both for your assistance.

There is no VR65 fitted.

All I have is a honeywell room stat and the drayton control programmer.

You say to set the bolier stat to 5 degrees above the unistor set temperature - assuming you mean the bottom knob which controls the temp of water circulating through the rads and coil in the unistor as opposed to the hot water top knob, as it does nothing on system boilers??

Thanks again to both of you esp for the book.

 

[uncleg]

Thank you both for your assistance.

There is no VR65 fitted.

All I have is a honeywell room stat and the drayton control programmer.

You say to set the bolier stat to 5 degrees above the unistor set temperature - assuming you mean the bottom knob which controls the temp of water circulating through the rads and coil in the unistor as opposed to the hot water top knob, as it does nothing on system boilers??

Thanks again to both of you esp for the book.

 

[D_Hailsham]

You say to set the bolier stat to 5 degrees above the unistor set temperature - assuming you mean the bottom knob which controls the temp of water circulating through the rads and coil in the unistor as opposed to the hot water top knob, as it does nothing on system boilers??

I think G4U was referring to the top (HW) stat. The boiler temperature is controlled by the bottom thermostat, which needs to be set according to the weather, not the HW temperature.