Vaillant Ecotec 630 - Flow Temp

[Graeme Stewart]

Ok so am looking for a bit of guidance.

Last year I had a Vaillant ECOTEC 630 Plus (System Boiler Version) installed to upgrade an old Keston something or other.

According to the manual (and if I am reading it right) I should be able to set a target flow temp for the when the water Cylinder is calling for heat and a different flow temp when it is only the heating calling for heat.

Currently, on the LCD control panel I can only set the temp for the heating as there is no option shown for the hot water.

The house is underfloor heated throughout with no radiators which means ideally I would like a target flow temp of about 50 as this is what the manifold brings it down to anyway before it goes into the floor. (The boiler is set to 75 to get the cylinder to 60 when it needs it).

My question is, could it be possible the boiler has been wired up incorrectly and doesn’t know the cylinder is there or is what am looking to do not even a thing and am misreading the manual.

TIA

 

[Brambles]

You are reading the instructions for the two channel version, or your boiler has been reconfigured for one channel operation

Your hot water temp is determined by your cylinder stat setting - but you know that

 

[ShaunCorbs]

Any pics of the boiler / pipework going into the boiler ?

 

[Graeme Stewart]

Any pics of the boiler / pipework going into the boiler ?

Offft, you are going regret asking for these...... I still cant really follow it and have been in the house 3 years!

Pipes into the Boiler

Full Pipework

Boiler Function Code

So I am reading the manual as when it is heating water only it should have code S.24 but in reality it is saying S.04 which makes it make think the cylinder has been connected as part of the heating circuit as that is the code for heating.

Also the simpleton in me thinks there are two cables going into the boiler. One for power and one for the heating? Should there be a third for the cylinder? I have had a look at the install manual and apparently there is a contact for "Cylinder Contact C1/C2" so I was thinking should there be a third cable to there?

BTW I have an extremely limited knowledge of plumbing so I could be doing 2+2 and getting 6 so if I am being thick please say.

 

[Graeme Stewart]

You are reading the instructions for the two channel version, or your boiler has been reconfigured for one channel operation

Your hot water temp is determined by your cylinder stat setting - but you know that

That's a fair point.

I do not have a central control point to switch off the heating. It all runs off individual thermostats in each room which can all switch the boiler on. Maybe the cylinder is just connected into the same junction box making it single channel?

When the boiler was install I asked them to put in a controller for the cylinder to add time control as is was only on thermostat control before which is the white panel in the pic above but they didn't touch the original wiring.

 

[chris watkins]

You are correct the boiler needs a sensor installed so that it knows when the hot water cylinder needs heating & can increase the temperature of the water it is sending out the heat it up.

If you want the boiler heating to work correctly with the U/F system you will need to find a specialist heating engineer to make some adaptions to the pipe work & controls. It needs hydraulic separation & removal of the auto-bypass.

 

[chris watkins]

Looks to me like a diy job all those mixed fittings, safety valve discharging into overflow etc etc.
What part of the country are you ?

 

[Graeme Stewart]

Looks to me like a diy job all those mixed fittings, safety valve discharging into overflow etc etc.
What part of the country are you ?

Thanks Chris.

I will need to find a UFH specialist, something which seems to be a very rare thing where I am (Glasgow).

I have the original plans for the system from when the house was built which interestingly don't cover the attic install so wouldn't surprise me if it was a bit of a DIY situation.

Might also explain the uneven floor boards upstairs if they have been getting cooked for 15 years but that is another problem!

 

[chris watkins]

Hopefully you have received a link in a PM if not please let me know.

 

[Harvest Fields]

Hopefully you have received a link in a PM if not please let me know.

Does that mean it is one of your Chris?

 

[SimonG]

By eck that's rough.

Is that a hint of an unvented cylinder?

 

[EvilDrPorkChop]

You won't be able to set temperature of the Cylinder as it doesn't look like you've got the matching Vaillant controls.

Having the Vaillant VR66 wiring centre, Vaillant temp probe and a matching Vaillant control panel will allow you to have HW priority, allowing you to set the flow temperature of the cylinder, KW input for the coil and the set point of the cylinder. Without this the boiler will just use the standard Switch Live from your existing controls and therefore cannot determine between heating or HW demand.

 

[Graeme Stewart]

By eck that's rough.

Is that a hint of an unvented cylinder?

Yes it is with another expansion tank tucked round the back. It's quite the *cough* system I gather.

 

[chris watkins]

Does that mean it is one of your Chris?

It would be a bit of a trot even for me.

 

[chris watkins]

You won't be able to set temperature of the Cylinder as it doesn't look like you've got the matching Vaillant controls.

Having the Vaillant VR66 wiring centre, Vaillant temp probe and a matching Vaillant control panel will allow you to have HW priority, allowing you to set the flow temperature of the cylinder, KW input for the coil and the set point of the cylinder. Without this the boiler will just use the standard Switch Live from your existing controls and therefore cannot determine between heating or HW demand.

Can you still use the temp prob to control an unvented ?
I haven't done one of these but been to a few Evo's were the muppets have ripped out stats & replaced with prob.

 

[EvilDrPorkChop]

Can you still use the temp prob to control an unvented ?
I haven't done one of these but been to a few Evo's were the muppets have ripped out stats & replaced with prob.

Yes, Vaillant say on their own tanks you can just use their probe. On any other tanks I use the probe, but wire the cylinder & high limit stat in also with the MV (turn the stat up to max). So if the probe was to fail the Cylinder Stat would kick in, and failing that the high limit stat would kick in also closing the MV.

This is how I also wire the EvoHome systems I fit (Leaving the Dual Stat wired up, turned up) so in effect you've got 3 fail safes.

 

[chris watkins]

Yes, Vaillant say on their own tanks you can just use their probe. On any other tanks I use the probe, but wire the cylinder & high limit stat in also with the MV (turn the stat up to max). So if the probe was to fail the Cylinder Stat would kick in, and failing that the high limit stat would kick in also closing the MV.

This is how I also wire the EvoHome systems I fit (Leaving the Dual Stat wired up, turned up) so in effect you've got 3 fail safes.

Good to know many thanks.
I know they had the dispensation on their own tanks but that is a sensible solution on the others.

 

[EvilDrPorkChop]

Good to know many thanks.
I know they had the dispensation on their own tanks but that is a sensible solution on the others.

Yes, otherwise they'd never meet regs. Doing it that way, it's only another control and the existing stats are still in place.

The HW priority system works quite well on the Vaillants too when you use their wiring centres. So much so I've wired Evohomes to do HW priority too.