Central heating not heating house to desired temperature - Weather Compensator

[matthew.austen]

I had a new Vaillant Boiler (ecoTEC plus 831) and Weather Compensator (VRC 470f) fitted a while back but during the recent cold weather have noticed the house isn't reaching temperature.

I have the desired temperate set at 21oC but on cold days it can take hours for the house to reach this temperature when the outside temperature is around 5oC. I've noticed the radiators are generally warm but not hot and the boiler display shows the central heating water is around 40oC. The night temperate is set at 18oC and regularly drops below this level.

At first it though it maybe a problem with the radiators and plumbing which is quite old but now not sure as I don't think the boiler is heating the water hot enough. Surely when it's cold and the desired temperature hasn't been met the boiler should be heating the water up to 75oC?

Any ideas what could be causing this issue? Hot water provided by the boiler is fine.

Thanks in advance.

 

[scorps]

Speak to Vaillant these weather compensators are'nt set as a roomstat out of the box so until it is set-up as a roomstat it wo'nt work.I can't find anywere in the instuctions explaining how you do this.On the two occasions Iv'e fitted them a Vaillant eng.had to come out to set it up,I was'nt there to learn how he did it

 

[matthew.austen]

I'd prefer to use the product as designed. I also get the same issue when setting it in party mode which I understand makes it work like a room stat.

Thanks

 

[doitmyself]

The heat curve is too low. It's probably set to about 1 and should be nearer 2.

Some experimentation will be required to get it right.

Read the 470f Installation Manual

 

[Baloo790]

Are these weather compensators a gimmick?

 

[Ermintrude]

No they really work well when set up properly.

 

[dancinplumba]

They only work well in well insulated properties

 

[Ermintrude]

Easy test push the two buttons on the boiler with a ladder and two brackets under them. Push and hold them together. Boiler will take off and rads will melt defo comp issue

 

[Baloo790]

Hmmm, maybe I will give one a go.

 

[Ermintrude]

It's not going to cause any harm its called "chimney sweep"

 

[Rabbitman]

Not sure I can say this as I'm If it's the new ecotec then the heating output comes set on auto this should adjusted to a suitable output for the property also as for the 470 the heat curve for the uk is 2.5 and if the unit is wall mounted then there's a setting in the installer level were you tell it its a thermostat, all this an be done without removing the appliance casing and the information found in the instructions

 

[dmheat]

Definately the heat curve adjustment required.

They come set for German/scand super well insulated properties. They still work really well in most houses but do need correct adjustment of the heat curve. Vaillant tech line will be able to help with how to adjust appropriately to suit your property. Once adjusted to suit it can and will work better than a standard prog/stat

 

[townfanjon]

As said a few times the heatcurve needs adjusting, it will take a few attempts to get it right. Keep at it, it will save you gas, i have it at home and wouldnt be without it .
valiant tech should be able to help you over the phone.

 

[tamz]

They only work well in well insulated properties

Where you been hidin Steve :wink:

 

[matthew.austen]

Thanks for all your comments. I've adjusted the heat curve to 2.0 which has made a big difference the radiators are getting a lot warmer. However I now have the opposite issue, we have the desired daytime temperature set to 20oC but the heating doesn't switch off when this is reached. This evening the temperature hit 22.5oC before I had to place the thing in away mode to switch the heating off!

Any ideas why the heating fails to stop when the desired temperature is met?

Thanks in advance.

 

[scorps]

Thanks for all your comments. I've adjusted the heat curve to 2.0 which has made a big difference the radiators are getting a lot warmer. However I now have the opposite issue, we have the desired daytime temperature set to 20oC but the heating doesn't switch off when this is reached. This evening the temperature hit 22.5oC before I had to place the thing in away mode to switch the heating off!


It needs setting as a roomstat I said that in the first reply and others have also mentioned it

 

[doitmyself]

However I now have the opposite issue, we have the desired daytime temperature set to 20oC but the heating doesn't switch off when this is reached. This evening the temperature hit 22.5oC before I had to place the thing in away mode to switch the heating off!

Is the receiver mounted on the wall or in the boiler?

Have you tried a slightly lower curve, e.g 1.8?

What is the setting for: Installer level - System Config - Heating 1 - Room Temp Control?

 

[Ermintrude]

Location of stat?

 

[dmheat]

It's overshooting (previously under) where the heat curve has been raised too high. As above, confirm settings and lower curve slightly to a point where during heat up the ambient temp hits 20deg and not much more. The boilers flow temp and gas rate will then be adjusted by the boiler to maintain more or less constant temp, rather than traditional on/off room stat action.

Youre getting there....lol

 

[Rabbitman]

The heat curve for the UK is closer 2:5 with the boiler stat set to max. Should the unit be external to the appliance then two further settings will require altering in the installer level they are room temp control to thermostat and system off mode to set back, if fault persist then there maybe a location problem as the default setting is to keep the appliance on in the event of an RF issue, this to can be checked and rectified if required

 

[Ermintrude]

If you have high volume rads with moderate surface areas (big cast iron ones) overshoot is common . Get a decent smart start / initiative stay.

 

[doitmyself]

The heat curve for the UK is closer 2:5 with the boiler stat set to max.

I would have thought the heat curve depended on the level of insulation in the house.