Anyone familiar with this setup?

[Scott_D]

Vaillant system boiler.
Vaillant cylinder.

Drayton 3 port and no 2 port to cylinder.
It’s 18 years old and they want to replace the boiler but keep the cylinder.

Was this ever an acceptable way of doing it?
Will I mess anything up by repipe group as an s plan?

 

[townfanjon]

even at 18 years old I would say at that time they would want a two port as well as the 3 ,
I would just change it to an s- plan , but in the real world I would change the cylinder .

 

[EvilDrPorkChop]

It's not a 3 port as you think. It's a diverter.

It has HW priority so it'll rapid reheat the small Unvented. They do them with small unventeds like this in Germany all the time.

If you change it to S plan you will need to ensure it stays HW priority and fit the new matching Vaillant controls (Assuming you're fitting another Vaillant.

 

[Scott_D]

It's not a 3 port as you think. It's a diverter.

It has HW priority so it'll rapid reheat the small Unvented. They do them with small unventeds like this in Germany all the time.

If you change it to S plan you will need to ensure it stays HW priority and fit the new matching Vaillant controls (Assuming you're fitting another Vaillant.

Yes another Vaillant probably a 624 but they want a nest fitted.
Is a boiler of that age 'smart' enough to do PDHW?

 

[EvilDrPorkChop]

Yes another Vaillant probably a 624 but they want a nest fitted.
Is a boiler of that age 'smart' enough to do PDHW?

Yeah it was the way they were designed and how it works with the diverter. It'll have to heat the cylinder before diverting to the Heating.

If they want to keep the cylinder they'd need the Vaillant Controls such as the SensoHome or SensoComfort with the VR66 wiring centre and VR10 probe. Or you'd have to get creative with the wiring with relays and stuff.

What size is the Unvented and what output is the current boiler?

 

[Scott_D]

Yeah it was the way they were designed and how it works with the diverter. It'll have to heat the cylinder before diverting to the Heating.

If they want to keep the cylinder they'd need the Vaillant Controls such as the SensoHome or SensoComfort with the VR66 wiring centre and VR10 probe. Or you'd have to get creative with the wiring with relays and stuff.

What size is the Unvented and what output is the current boiler?

The boiler is a 628
Cylinder is 150L
The existing controls are just a standard drayton 2 channel timer

 

[king of pipes]

18 years old I'd be recommending its changed it wont last much longer especially putting a new boiler onto it . Kop

 

[EvilDrPorkChop]

The boiler is a 628
Cylinder is 150L
The existing controls are just a standard drayton 2 channel timer

I might be wrong, but that's how they were always designed to be used. The diverter will use the cylinder stat to know when the cylinder is up to temp then switch over if required.

 

[Scott_D]

I might be wrong, but that's how they were always designed to be used. The diverter will use the cylinder stat to know when the cylinder is up to temp then switch over if required.

I agree the cylinder should also be replaced but if they say no, would the replacement boiler work connected to the existing setup?

 

[EvilDrPorkChop]

I agree the cylinder should also be replaced but if they say no, would the replacement boiler work connected to the existing setup?

Yeah but I’d convert it to S Plan and new Vaillant controls.