Nest - Call for heat not working, but hot water is

[Mike Young]

Wired up a v2 nest before, no probs. Version 3 has hot water also.

I have a Nest V3
Programmer was: - Potterton EP2002 (2 channel - Hot water and Heating)
1 x 3 port valve
1 x Hot water tank - Not plugged in, as gas heats all water. (never been plugged in)

I have the following connections from Nest to Programmer
NEST: 1 2 3 4 5 6

PROG: - L 4 - L 3

The call for HOT water works when hot water is asked for via app/thermostat etc.
The call for Heating does not, No sounds etc (Yes there is voltage on terminal 4 Programmer, the relay does click on when asked.) System all working before.

QUESTION 1 : Do I need to add the other connections that nest said...like below....
"As stated during the call, terminals 1 and 4 on the Nest, which are the satisfied for each switch, are not usually necessary. "

NEST: 1 2 3 4 5 6

PROG: 2 5 4 1 L 3


QUESTION 2 : It seems when call for heat the pump does not start as usually it would start and gushing sounds are heard, but this is not the case. I feel that there is a live missing, and the pump does not know to start. How do I rectify?

Any help appreciated.

 

[Agile]

Don't you think telling us the boiler model might be important?

 

[Mike Young]

Ok Nest never asked me for this.... but here it is Sir.....

Ideal

Boiler Manual http://library.plumbase.co.uk/flipbooks/RE/idclaslxff250_22003_t/mobile/index.html#p=2

 

[Agile]

The significance of that is that the pump is not controlled by your ( rather old ) boiler but by the call for heat.

I avoid giving advice on wiring of controls because I am so scared of anyone damaging their equipment be wrongly wiring something.

Tony

 

[hertsboilers]

"4" on Nest should also be connected to the wire which was on "1" of Potterton EP2002 before.

 

[hertsboilers]

Sorry, but did you remove the old programmer?

 

[Mike Young]

The timer front i have taken off. But backplate i have left. The nest controls the timings now.

All original wiring is as the photo

 

[Mike Young]

Just connected nest 4 to potterton 1
(NEST EMAILED ME THIS, TOO)

No change...HW works Heating does not

Added nest 1 TO potterton 2 and this also is the same result. (Also like nest said)

The links they said usually not needed have been added...no change???

 

[hertsboilers]

For three port valve, it is a Y plan, you need three signal outputs from any programmer, either Nest or EP2002. They are: hot water off, hot water on and heating on.

If you are sure the heating on is connected correctly, then check further to the three port valve.

 

[hertsboilers]

Just connected nest 4 to potterton 1
(NEST EMAILED ME THIS, TOO)

No change...HW works Heating does not

Added nest 1 TO potterton 2 and this also is the same result. (Also like nest said)

The links they said usually not needed have been added...no change???

check if you have a 230v to the white wire of the three port valve, for most of middle position valves.

 

[Mike Young]

White, brown, blue, yellow, yellow/green, comes up in a cable.

White goes to C and connects to another white.
Brown = prob live as it is in port A
Yellow = 1
Blue = nuetral
Yellow/green = earth

I take its the pump?

Any help....

 

[Mike Young]

Just manually put on nest box. This turns on heating and hot water.....no voltage on white wire. That seems to be all i can test.

The white wire being tested at programmer backplate

 

[hertsboilers]

Just manually put on nest box. This turns on heating and hot water.....no voltage on white wire. That seems to be all i can test.

Make sure 5 of the Nest is having 230v power.

 

[Mike Young]

Called nest installer....

Everything was wired up correctly...

But.... when i added nest thermostat I just taped up old wires and held in place behind wall. They needed to be joined then hidden. They gave power to somewhere else.

ANSWER : Join existing thermostat in living room wires together when replacing with nest.....


Thanks for your help... anyway....

 

[zappermac]

Called nest installer....

Everything was wired up correctly...

But.... when i added nest thermostat I just taped up old wires and held in place behind wall. They needed to be joined then hidden. They gave power to somewhere else.

ANSWER : Join existing thermostat in living room wires together when replacing with nest.....


Thanks for your help... anyway....

Dear Mike,

I am facing the same problem. I have prt100 thermostat. Should I connect all the three wires and put them behind the wall ? Or only two. Please help. Thanks