Vailliant sustain 418 heat only problem

[diycooper]

I have just got a new vailliant sustain 418 installed to replace old icons.

Prior to install heating and hot water working. Had new 3 port valve last oct. And had full system power flush 4 months ago and inhibitor added.

New boilor in and wired by engineer. Boilor calls for heat and this works.

When turn hot water on there 240v at boilor but the boilor does not fire up.

Engineer does not know what it is.

Any idea ?

 

[Mottie]

Have they removed the 24v link? I had problems with mine on the day of the install. Vaillant boilers are set up to use Vaillant controls that run on 24 volts. If you use other equipment, you just have to remove the 24v link from the circuit board.

 

[diycooper]

Have they removed the 24v link? I had problems with mine on the day of the install. Vaillant boilers are set up to use Vaillant controls that run on 24 volts. If you use other equipment, you just have to remove the 24v link from the circuit board.

Not sure if the link was left in would heating work but not hot water off controls

 

[Mottie]

Not sure if the link was left in would heating work but not hot water off controls

Mine was all over the place. Heating worked, hot water just kept running - on the first night I had to pull the fuse for the boiler and turn the gas off. Vaillant told me what it was so I sorted it myself while waiting for the 'engineer' to call me back in the morning. Vaillant technical line said it was VERY common!

 

[diycooper]

Have they removed the 24v link? I had problems with mine on the day of the install. Vaillant boilers are set up to use Vaillant controls that run on 24 volts. If you use other equipment, you just have to remove the 24v link from the circuit board.

Not sure if the link was left in would heating work but not hot water off con

Mine was all over the place. Heating worked, hot water just kept running - on the first night I had to pull the fuse for the boiler and turn the gas off. Vaillant told me what it was so I sorted it myself while waiting for the 'engineer' to call me back in the morning. Vaillant technical line said it was VERY common!

Thanks. I did ask him.did he take the bridge out yesterday he said yes. But ive just sent him.vailliant diagram with the 24volt link and asked him.did he remove that exact link.

 

[Mottie]

Not sure if the link was left in would heating work but not hot water off con

Thanks. I did ask him.did he take the bridge out yesterday he said yes. But ive just sent him.vailliant diagram with the 24volt link and asked him.did he remove that exact link.

After my experience, I have mentioned it to a few people on here with Vaillant problems and on a few occasions, I have been right. Even a blind squirrel will did up a nut now and then!

 

[diycooper]

After my experience, I have mentioned it to a few people on here with Vaillant problems and on a few occasions, I have been right. Even a blind squirrel will did up a nut now and then!

Ha ha. I hope it is just the link. Thanks

 

[CountryFan]

I doubt it’s the link, usually just for heating. Either wired up wrong, fault with programmer or cylinder thermostat.

 

[diycooper]

I doubt it’s the link, usually just for heating. Either wired up wrong, fault with programmer or cylinder thermostat.

Thing is everything was working on old boilor prior to install..

Controls pretty new and thermostst on cylinder less than year old.

Can you explain what you mean by doubt its the link usually just for heating ?

Thanks for helping