Vaillant ecoTEC 428 plus. (VUGB286/2-OH)

[CRA19D]

Hello,
Firstly please excuse my lack of knowledge with heating systems, ill Try and explain what I’m Trying to achieve the best I can.

As per the description I have a 428 heat only boiler recently converted from open vent to a sealed system. This is operated by a Yplan and Hive controls.

The boiler has 2 dials on the front with the option to control both the radiator and water temperatures separately.
When I try and heat either the radiators or the water cylinder the boiler only achieves the temp that the radiator dial is set at.

Unfortunately the water dial d temperature does is never achieved and I’ve been made aware it won’t while I try and control it with Hive.

My question is would utilising the the eBUS Connection by replacing Hive with the latest Vaillant controls give me better control of the boiler? VR66 and Sensohome?

Ideally I’d like the flow temp from
The boiler to be around 40-45 degrees when heating radiators is requested which would increase to 65 when hot water is called for.

Basically want the heating ticking over but the cylinder heated up much quicker when it’s requested. I understand this would increase the temp of the flow to both the rads and the cylinder but would only be for an hour or so in the morning.

Hopefully I’ve made some sense, and someone with knowledge could tell
Me if this old boiler can be controlled the way I want.

Thanks in advance
Craig

 

[CBW]

From the sound of it you want a hot water priority system, which uses the normal heat for hot water and reduced heat for heating. This might not be achievable with your boiler, but could be if using Vaillant controls. @Sim777 or @ScottishGasMan might be the men for this. You can’t alter the hot water temperature because your cylinder needs to be 60 degrees to kill any bacteria.

 

[CRA19D]

Hi @CBW
Thanks for the reply!
yes that definitely sounds like what I’m after.
I am running the temp low at the moment but once a week crank the temp up to avoid Legionella. Not the end of the world having to turn the dial up on the boiler but would much prefer it to be automated.

Hopefully @Sim777 Or @ScottishGasMan Could advise. I’ve asked a couple of local companies but they can’t help.
Surely the boiler has been designed with separate temperature dials for a reason.

 

[Sim777]

Yes VR66 and senso home will allow proper hot water priority and modulated central heating at lower temperatures. Well worth doing with current gas prices.

Trouble is getting hold of vr66 or vr70

Vr66 allows for use of existing cylinder stat. Vr70/71 requires a NTC connected to the cylinder which may be difficult if the boiler is not close to the cylinder

It may be possible to use glow worm wiring centres if vr66 is not available, but I have not tested it.

 

[CRA19D]

Hi @Sim777

Thanks for coming back to me, great news!!

Sorry for my ignorance but what is an NTC?
There is some distance between the cylinder and boiler, around 10meters! Boiler being in the garage and the cylinder in the loft.
What issues would I possibly have with the distance between the two or is it just cabling?

Thanks again
Craig

 

[Sim777]

Hi @Sim777

Thanks for coming back to me, great news!!

Sorry for my ignorance but what is an NTC?
There is some distance between the cylinder and boiler, around 10meters! Boiler being in the garage and the cylinder in the loft.
What issues would I possibly have with the distance between the two or is it just cabling?

Thanks again
Craig

Yiu may have to run additional wiring for NTC and ebus

If you can get vr66 then you should be able to do it without additional wiring

 

[CRA19D]

Cheers Sim777

I’ll have a look into it!
Your advice is much appreciated.

 

[CBW]

NTC - Negative Temperature Coefficient - perhaps he means a thermistor.

 

[Sim777]

NTC is just a cylinder sensor. You have to use it with vr71/70

 

[rhinoman]

I have the same boiler and added VRC700 and VR70 wiring centre, I squeezed the NTC in behind the original cylinder stat.

This setup will do exactly what you want. We have two heating zones UFH and Rads and PDHW. The weather-compensated heating hasn't got over 50C yet even when we were -1 a few weeks ago and has been typically under 40C the last few weeks. The hot water we run at 50C other than a once-a-week cycle to 60C for legionella, this is all programmed via the VRC700.

 

[CRA19D]

Thanks @rhinoman

These positive answers are giving me hope

Can I ask what cylinder you have, I read that these systems are best paired with a Vaillant cylinder but I’ve had a Gledhill solar lte installed 3months ago. I presume it will be fine sliding the NTC thermostat pocket of the gledhill or even utilise one of the additional solar pockets.

I better start writing a shopping list.

 

[Sim777]

Yes you can slide NTC into the pocket or behind insulation

You will need

VRC720 for one zone and dhw
Vr70

If you have more zones than 1 then you ned
Vr71
Vrc720
Vr92

If you have more than 2ch zones plus dhw you need

Additional vr70 per 2 zones plus vr92 per zone

You can also use 3rd party controls for other zones with vr71

You need someone clued up on how to configure and install it.

 

[CRA19D]

Thanks @Sim777

It’s finding someone local that’s been my problem, one of the reasons I’ve reached out to you guys.

When you say 3rd party controls would that include hive?

I was just planning on getting rid of hive altogether and change everything to Vaillant

I only have one zone for central heating so nothing fancy going on there.

 

[Sim777]

Yes then all you need is

Vr70
Vrc720 or vrc700

No need to use hive anymore

 

[rhinoman]

Thanks @rhinoman

These positive answers are giving me hope

Can I ask what cylinder you have, I read that these systems are best paired with a Vaillant cylinder but I’ve had a Gledhill solar lte installed 3months ago. I presume it will be fine sliding the NTC thermostat pocket of the gledhill or even utilise one of the additional solar pockets.

I better start writing a shopping list.

I have a Gledhill too, about 14 years old in my case. The NTC fitted into the tube the tank stat uses.