Recent content by jackthom

I know this is an old thread but I’ve found it very useful over the past few years. My Vaillant boiler was installed in 2007 and probably won’t keep running very much longer. Can anyone confirm whether the latest incarnation of the Vaillant open vent boiler will listen to the VR65 via ebus when...

From the picture, 4 and 5 on the thermostat do the switching so connect one of them across to Live with a short wire and connect the other to RT on the boiler plug where you have tapped off the mains power. That’s the turquoise plug, NOT the 24V one.

Heard the interview of a network manager on the Today programme this morning who reckoned Heathrow has three feeds from the national grid. Two of them come via the substation in question but a third is from a different source. Unfortunately Heathrow don’t appear to have the ability to simply...

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It’s still not clear whether the boiler cycling is the result of the return feed being somehow at a high temperature, which seems unlikely unless there is a short circuit bypass we don’t know about, or for some reason the flow through the boiler is actually reduced when both UFH and Radiators...

At full system startup when the boiler quickly brings the flow temp over 65C and is about to cut out what is the return temp? I’m assuming it must be fairly high and if so what path is this hot water taking through the system? If on the other hand the return temp is low there isn’t enough flow...

When you say the heating is not getting up to temp do you mean the radiators are not getting as hot as they used to?

Can you post some pictures to show the layout?

Does the pump have a number of speed settings and if so which is it set to. I have to run my own Vaillant on the highest setting in order to avoid similar problems.

I had to do this several years ago and it was fine except my Vaillant wasn’t happy if the water level in the bucket rose above the bottom of the pipe. Still can’t get my head around exactly why, but it resulted in a small amount of condensate flowing over from the trap into the boiler casing.

Apologies, I'm still struggling to follow the red wire from Heatlink terminal 3. It should be connected to the 3 port valve white wire but I can't see where it goes.

Can you post a photo taken from the left side of the wiring centre. It's hard to see exactly what's connected to the LHS of the terminals.

Not clear in the photo where in the Heatlink the first brown Live link is connected. Is it from L to terminal 2 as it should be?

The 450 can automatically alter the heating flow temperature setting depending on the outside temperature. Is there a connection to an exterior thermostat? I don't have any experience of using or setting up one of these units so hopefully someone else here will be able to advise on your options.

Hi, do you have any Vaillant controls connected which may be overriding the target temperature you are manually setting?