Nest install seems okay but not convinced it's working!

[Hot&Cold]

The heating system is all brand new so I would like to think it worked.

A quick check of the system bypass,it may be fully open when it need not be.

 

[Agile]

Yes, quite so, but with the boiler apparently working and the zone valve open then the rads are expected to be heating up.

The TRVs are an item, really the only one, which could be preventing most rads from heating up.

Merely connecting the Nest will not have made any difference to the system. So was it really working before the Nest was fitted?

 

[Agile]

The full advantage of the latest Nest is only obtained when it is connected to use the Weather Compensation feature to modulate the boiler flow temperature control with an Open Therm connection.

A mere on/off control is not using it to its full advantage.

Tony

 

[sparkymark75]

Yes, quite so, but with the boiler apparently working and the zone valve open then the rads are expected to be heating up.

The TRVs are an item, really the only one, which could be preventing most rads from heating up.

Merely connecting the Nest will not have made any difference to the system. So was it really working before the Nest was fitted?

Good question, one I asked myself and I stupidly never tested it before removing the TP5000s.

 

[sparkymark75]

The full advantage of the latest Nest is only obtained when it is connected to use the Weather Compensation feature to modulate the boiler flow temperature control with an Open Therm connection.

A mere on/off control is not using it to its full advantage.

Tony

. My system has a Honeywell outdoor temperature sensor in it. I did intend to hook it all up using OpenTherm but was advised that won't work with a dual zone system with Nest.

 

[Hot&Cold]

My system has a Honeywell outdoor temperature sensor in it. I did intend to hook it all up using OpenTherm but was advised that won't work with a dual zone system with Nest.

So the outdoor sensor is not connected and the boiler is not set up for open therm switching,next you will tell us something like its got several frost thermostats etc.

Did yiu try the system bypass ?

 

[sparkymark75]

So the outdoor sensor is not connected and the boiler is not set up for open therm switching,next you will tell us something like its got several frost thermostats etc.

Did yiu try the system bypass ?

I haven't disconnected the outdoor sensor so it'll still be wired in. I didn't wire the Nests in for OpenTherm as I believe it's not supported for a multizone system.

It's only got one frost stat.

I read up on the system bypass but didn't want to adjust it as it seems its set when the system is commissioned. The plumbers have been round, bled the radiators and will come back tomorrow morning when the system is cold.

 

[Hot&Cold]

Hope you get it sorted

 

[muggles]

From the Nest Installation Manual (my emphasis):

The Heat Link and Nest Thermostat communicate wirelessly, even if they are also connected by cables.

So how do you explain a Nest which works when it's not connected wirelessly? Wired communication is the only answer

 

[Phill Peck]

So how do you explain a Nest which works when it's not connected wirelessly? Wired communication is the only answer

I could be wrong but I was under the impression communication was always wireless. Sane with Honeywell lyric

 

[Agile]

. My system has a Honeywell outdoor temperature sensor in it. I did intend to hook it all up using OpenTherm but was advised that won't work with a dual zone system with Nest.

The advised reason that two Nests, one for each zone, would not work on the open therm ( OT ) is that the boiler can only accept one OT connection at a time.

The Nest uses the OT to bring on the boiler as well as set the boiler control temperature.

Even switching each OT to the boiler is likely to give some incorrect operations.

 

[D_Hailsham]

The advised reason that two Nests, one for each zone, would not work on the open therm ( OT ) is that the boiler can only accept one OT connection at a time.

A more fundamental reason is that you can't have a boiler running at two different flow temperatures at the same time This would happen if, for example, one zone was set to a 20C required temperature and the other zone for a 16C temperature. 20C may require a flow of 75C, 16C a flow of 65C. It all depends on the heat loss from the house.

 

[D_Hailsham]

So how do you explain a Nest which works when it's not connected wirelessly? Wired communication is the only answer

I can't. Nest need to get their act together and make sure the published documentation is correct.

 

[sparkymark75]

Okay so I'm thinking this is down to a couple of things.

1. My mis-understanding of the zones. Zone 2 is labelled as "Upstairs". However, it only covers the master bedroom and the ensuite to that room. I assumed by "upstairs" it literally meant, upstairs. The other zone, labelled "downstairs", covers the rest of the house.

2. Now that the radiators have been bled and I understand the zones better, I cranked zone 2 up to 25c (ambient was 21c). The radiator in the ensuite and the master bedroom heated up.

I've not tested the other zone yet but I'm hoping for the same result.

 

[sparkymark75]

I can't. Nest need to get their act together and make sure the published documentation is correct.

If you tested it by switching of your wifi then it'll still work wirelessly. It uses its own wireless network to communicate with the Heat Links, not your own household wifi. It only uses that for external communication (so you can control it away from home, etc) and for updates.