Swapping out nest heat link

8 Nov 2020
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United Kingdom
Hi, I have had a Nest thermostat and heat link installed for a couple of years now and just don't get on with it. We constantly have cold bedroom due to the start being in the lounge and shutting off the boiler when that room is warm. I have stats on every radiator but have never been able to cure the issue. So, the I am looking at the Drayton Wiser system as an alternative. My question is, how difficult would this be as there is no common interface on the heat lnk is there?
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It sounds like your system just needs balancing. What makes you think Wiser will fix it?
Hi, I thought the option for the integrated rad stats will help I thought. The only option I seem to have is back off the lounge rad start and set the nest at a higher temp. I am not a heating eng so any help is useful. My other option for better control would be Tado. With my old system and stat in hall Things seemed better
Even with individual rad stats the system will need balancing for best effect. Get that done first then consider changing controls. There's an FAQ on how to do it at the top of the forum
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On so I have read the FAQ and seems straight forward. However, I have no idea what is the first, second etc. Rad in my system. Since it was installed I have had additional rads in an extension and loft conversion. How can I identify the rad order?
Most thermostats are a simple on / off switch. They simply turn the heating 'on' and 'off' that's all they do. When the room in which they are located reaches the set point, off goes the heating. So, in your case swapping the thermostat won't change anything. When the lounge where the stat [Nest, Wiser, Hive, et al] is located reaches the set temperature the heating will still go off.

The problem is either with the design of the system, the thermostat is simply located in the wrong place or as muggles says the system needs balancing to distribute the heat more evenly.

Here's a guide as to where the thermostat should be positioned:

1. The room thermostat should be in a room that is not effected by other sources of heat such as an open fire, cooking equipment, or direct sunlight etc. It should not be somewhere drafty or too close to a window, especially if it's one that is opened in the winter.

2. It should be in a cool room, ideally the last room to warm up. That way the other rooms will be warm enough, (but not overheated if fitted with TRV’s) before the room thermostat switches the entire heating system off. [To achieve this, sometimes it may involve downsizing a radiator in the room where the room stat is located]

3. The radiator in the room with the thermostat installed should not have a TRV fitted. Otherwise the TRV could interfere with the operation of the room thermostat and prevent it from working properly.

4. The thermostat should be mounted about 1.5 metres from the floor, and not close to, or above a radiator.

5. Preferably it should not be on an outside wall, (although if the property has well insulated walls, this is not quite so crucial.)

6. It should be in an area where air can circulate easily, not in a corner, or hidden behind curtains, or furniture.
I thought smart TRVs would call for heat regardless of the main roomstat. I was looking at dayton wiser with extension kit.
OK, you didn't mention TRV's, but you're right they do call for heat from the Wiser Hub.
My question is, how difficult would this be as there is no common interface on the heat lnk is there?

They are different products, so the Nest Heat link would have to be removed completely before installing the Wiser.
Yes I get that, but the drayton looks more suited to my needs. Nest seems to lag innovation here compared to the USA. Not room sensors for example which would have maybe solved the problem I have. Only pain is nest not having std back plate on heat link. Thanks for your response.
With the Wiser solution, I'm not sure how it would work in conjunction with a room thermostat in the lounge though if there isn't a TRV on the lounge radiator. If the TRV's individually 'call for heat' and switch the heating on, then the lounge radiator will still get hot even if the room thermostat in there wasn't actually calling for heat.

Fitting a TRV to the lounge radiator would get around that, but then if you had a TRV and a room thermostat in the same room, one would interfere with the operation of the other.
I believe I would need the room stat in the hall maybe. There is a trv in the lounge thst could be changed. Currently withe the nest in the lounge i am confused whether to use the TRV in the lounge full on and all others set to room temp. Or set lounge TRV lower. If I do that room will reach temp faster and shut off heat anyway. I have never really understood the nest but bought it based on reviews....
So I've had a crack at balancing and to be fair failed... I find it impossible to identify to 1st, 2nd, 3rd rad etc rad in my system. So just for "fun" I turned up the heating and checked pipe temp on TRVs and lockshields on each. The results in this unscientific test surprised me:
On most rads the TRV temperature was higher than the lockshields. Is this correct? Results below with trv first then lockshield temps
Kitched 49.4 and 41.9
Lounge 40.9 and 49.4
Dining 37 and 43.9
Hall 40.9 and 44.9
Bath 41.4 and 42.9
Bed1 37 and 50.4 Coldest room in normal circumstances
Bed2 38 and 51.9
Loft rad1 50.9 and 42.9
Loft rad2 44 and 49.3
Loft toilet no trv or lock on small heated rail lh 47.8 and rh 52.4

So is it acceptable to just adjust all locshields to give 12 deg delta. Or must I balance in order 1 thru 9. As stated I cannot 100% identify rad positions in the system.
Any advise greatly appreciated before I get the pros in.

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