Nest with oil combi compatible?

[Millsy 82]

I wired up a nest with an oil combi and whilst the heating side works fine is the hot water side compatible?

It seems to me that it doesnt work with an oil combi so I just turned it off.

Am i right or wrong.

 

[ShaunCorbs]

It’s only on or off so should be

 

[Millsy 82]

I wired it up as you would imagine common from boiler to nest number 5 then back to boiler on 6 but didnt work.

 

[Harvest Fields]

I wired it up as you would imagine common from boiler to nest number 5 then back to boiler on 6 but didnt work.

Double check the wiring mate.

 

[ShaunCorbs]

I wired it up as you would imagine common from boiler to nest number 5 then back to boiler on 6 but didnt work.

Did you try linking the nest out ?

 

[Harvest Fields]

I wired it up as you would imagine common from boiler to nest number 5 then back to boiler on 6 but didnt work.

Sure it should be 2 and 3

 

[Harvest Fields]

Photo of nest to combi wiring mate.

 

[ShaunCorbs]

Photo of nest to combi wiring mate.

View attachment 39734

Oils need a twin channel clock as it uses the buffer

 

[Harvest Fields]

Oils need a twin channel clock as it uses the buffer

Sorry mate. Didn’t realise as not oil trained. My bad.

 

[Millsy 82]

Did you try linking the nest out ?

Yes in the end I left it with no programmer on the hotwater and left it on constantly as the customer said they were happy with that. Now they would like it so they can turn it off.

It's been a couple of months since I was there and I cant remember what the problem was but I wired to 5/6 set it to combi and it didnt work (obviously only set up for gas combi so not needed) so i then set it as a system boiler and for some reason wouldnt work again. I will go back and try it again.

 

[ShaunCorbs]

Yes in the end I left it with no programmer on the hotwater and left it on constantly as the customer said they were happy with that. Now they would like it so they can turn it off.

It's been a couple of months since I was there and I cant remember what the problem was but I wired to 5/6 set it to combi and it didnt work (obviously only set up for gas combi so not needed) so i then set it as a system boiler and for some reason wouldnt work again. I will go back and try it again.

That’s why needs to be set for sys or heat only etc

That side is disabled when you choose Combi

 

[Millsy 82]

I swear

That’s why needs to be set for sys or heat only etc

That side is disabled when you choose Combi

I swear I tried it on system and heat only but it just wouldnt work. I am going to book back in to try again and see.

 

[SimonG]

Unfortunately doesn't give control other than on or off. Designed for gas combis.

Did a lot of hair pulling, well if i had any to start with, the first time I came across it on an oil combi.

 

[Millsy 82]

Hello everybody.

Just spoken to nest regarding this problem that I had as I have just had the exact same problem on a system boiler.

What it is is the bacteria prevention is on causing the boiler to fire constantly for hot water.

To turn it off go

settings- equipment- bacteria prevention- disable.