I’ve had a plumber suggest using heat resistant 0.75mm 5 core to connect power and switching connections to a wireless thermostat relay.

 

Now 0.75mm is good for 6A , so technically I don’t see an issue as it’s on a 3A fused switch and the boiler has 2amp fused in it.

 

The manual for the stat states 1.5mm-2.5mm and as two separate cables not running next to each other.

 

Currently the 5 core flex carries power to the boiler and the wired stat connections back the the fused switch where the connect to the switch and to the thermostat wiring.

 

Can I ask any sparkles/plumbers if the plumber is wrong, is the manual being OT or something else?

 

looking at the wiring you need to send a permanent live and neutral to

the old thermostat location to supply power to the new wireless controller via a transformer in the controllers back box.

 

The boiler itself needs L N and Earth from the switch.

 

The wireless relay needs a permanent live and neutral plus the connection to the pair of thermostat wires on the boiler.

 

So would plumbers use 5 core to the boiler then from the boiler onto the relay, do something with 1.5/2.5 from the switch for power or something else?

 

Also the plumber suggested putting the relay by the switch, but this is surrounded by wire/metal and the boiler is 20cm away.

 

The alternative suggestion was to run 2.5mm and 0.75mm 5 core through the loft to the other wall of the cupboard and put it there.

 

Again is this safe?

 

Thoughts appreciated.

Edited 13 January, 20215 yr by cheezemonkhai

Had my new boiler and wireless thermostat fitted recently. 

 

Plumber used two x 5 core 0.75mm. (2 or 3 cores spare he told me / future use if wanted)

 

He has left the wiring diagram and done a pretty good job.

 

I would say manufacturers / manual instructions (or H&S regs) being OTT as is frequently the case. Probably not the H&S regs in this case tho.

 

You could ask the sparkies on the Screwfix forum for more professional advice but alike the 'Winner Takes All' programme of old, I bet you would still get a difference of opinion, Lol.

It got done and turned out the wiring when built is the 0.75mm heat resistant 5 core flex between the switch and the boiler, solid 3+ earth to the stat and 2.5mm solid on the power in side of things.

 

All sorted, and all protected by multiple 3A and 2A fuses at the boiler and the isolator.

 

Plumber pointed the fuses etc out and also that the only choices were heat resistant flex for the boiler connection.

 

Which system did you go for?

Smart stat was a Honeywell evohome in the end and I have to say it’s much better than nest etc.

 

It doesn’t directly have geofencing, which I never really fancied anyway. That however is more made up for by rooms as zones, optimised starts + stops and weather compensation

 

Wifi controller, pairs with a Honeywell brd91 relay (found in most Honeywell wireless stats) or their opentherm bridge.

Controller has a stand and a wall mount transformer which fits in a single gang back box. It’s neatly on a wall looking very sci-fi.

 

7 smart TRV and a separate room stat for one room where the trv is hidden behind something.

 

The app is pretty good and best of all it works properly bar the app even if there is no internet.

The biggest downside is the cost if you buy it all separately, but buy a starter kit and it’s not much more than a single zone nest/hive.

 

the control panel that looks like a mini tablet looks like it might be fun  

I probably could have worded that better ^^^  

30 minutes ago, Lady Elanore said:

the control panel that looks like a mini tablet looks like it might be fun  

You might find the hr91 more your thing, although the hr92 has adjustable stroke 😂

Edited 21 January, 20215 yr by cheezemonkhai

For your personal enjoyment 

You had me at the quad screen spilt 

I’m surprised more people don’t look at this system to be honest. Most of the parts even say made in UK which I didn’t expect.

 

I think the marketing of some of the single location smart systems has made people go all “shiny must have”

This thread should probably move to tech shed now... 

 

I have just discovered that the room TRV notices a large and persistent drop in room temperature (or a window contact sensor) and turns off as it assumes the window is open.  Sure enough, you end up with it not trying to heat a room when you've got the door open after moping the floor

 

Nice to see it can be disabled/enabled on a zone by zone basis too

What fridge did you buy in the end? (I posted in your fridge thread earlier) 

2 hours ago, Lady Elanore said:

What fridge did you buy in the end? (I posted in your fridge thread earlier) 

I replied on that thread for you (I'd completely forgotten about it tbh) 

So a brief update...

 

Gas consumption per day since installation day is approximately 20-30% lower than that from the last few gas bills.

 

Not been cold bar the first few days where we were testing/tweaking until the temperatures were set correctly in the rooms.

 

Considering that’s two cold months vs a mix over the last three quarterly bills I am more than happy that the system will more than pay for itself quite quickly. 👍

Further update in case anyone is looking for a new system.

 

Evohome has been fantastic.

All the rooms are individually set based on occupancy time and comfort is much improved.

 

Due to only using what you need when/where you need it, our gas bills were a good third below the previous years and I would say most of that is due to the change.

 

Sadly we don’t have an open therm boiler, but it’s a big jump. We’re actually warmer/more comfortable and have saved energy.

 

Anyone that’s considering a smart stat. Definitely add it to the list to consider 👍

On 21/01/2021 at 22:18, cheezemonkhai said:

Smart stat was a Honeywell evohome in the end and I have to say it’s much better than nest etc.

 

It doesn’t directly have geofencing, which I never really fancied anyway. That however is more made up for by rooms as zones, optimised starts + stops and weather compensation

 

Wifi controller, pairs with a Honeywell brd91 relay (found in most Honeywell wireless stats) or their opentherm bridge.

Controller has a stand and a wall mount transformer which fits in a single gang back box. It’s neatly on a wall looking very sci-fi.

 

7 smart TRV and a separate room stat for one room where the trv is hidden behind something.

 

 

 

 

You say its weather compensation?.....

 

Did you have to change the two-way valve on the boiler to radiator hot feed to a 3-way mixing with a feed from the radiator return??..Besides an outside temp sensor does it also have a temp sensor on the flow to the radiators (between first radiator in pipework & the valve for the rad circuit), & sensors on the flow immediately out of the boiler & one on the return immediately into the boiler??

 

As that's proper weather compensation...& I've had that system type in my home for the past 26yrs! 

1 hour ago, fabdavrav said:

 

 

You say its weather compensation?.....

 

Did you have to change the two-way valve on the boiler to radiator hot feed to a 3-way mixing with a feed from the radiator return??..Besides an outside temp sensor does it also have a temp sensor on the flow to the radiators (between first radiator in pipework & the valve for the rad circuit), & sensors on the flow immediately out of the boiler & one on the return immediately into the boiler??

 

As that's proper weather compensation...& I've had that system type in my home for the past 26yrs! 

Weather compensation using online data, so not as accurate as real compensation. 

The boiler has an integrated thermal store as opposed to a separate tank and I has plenty of flow temperature monitoring as well as a flow diverter to make sure it’s not heating if not needed.

 

No it’s not your system, but every room sets it’s own temperature, switches off if a window is open, has individual set points over a day and monitors how long each room takes to warms up/cool to optimise heat up/turn off.

 

I’d say it’s about as good as you can get in a house that has a standard Uk boiler and just a single stat/zone. That’s of course just my opinion, others may like their way, but it’s done what I needed here.

2 minutes ago, cheezemonkhai said:

Weather compensation using online data, so not as accurate as real compensation. 

The boiler has an integrated thermal store as opposed to a separate tank and I has plenty of flow temperature monitoring as well as a flow diverter to make sure it’s not heating if not needed.

 

No it’s not your system, but every room sets it’s own temperature, switches off if a window is open, has individual set points over a day and monitors how long each room takes to warms up/cool to optimise heat up/turn off.

 

I’d say it’s about as good as you can get in a house that has a standard Uk boiler and just a single stat/zone. That’s of course just my opinion, others may like their way, but it’s done what I needed here.

 

 

Mines a basic system boiler..just a firing chamber/heat exchanger & basic stat...

So yes different needs/goals.

 

Your way is probably more efficient, our house really required 2/3 zones, so this is cheaper than zone valves.

 

Its a good easy compromise 

19 hours ago, cheezemonkhai said:

So yes different needs/goals.

 

Your way is probably more efficient, our house really required 2/3 zones, so this is cheaper than zone valves.

 

Its a good easy compromise 

 

"My way" has been over in Europe since mid/late 1990's....

 

Its a basic WB condensing boiler, in fact any boiler will do...I chose one with the no pump, no bypass, no expansion tank, no controls (it still has a small amount of on board due to stat & safety) all so I could specify my own as external normal ones are cheaper to replace then "specific" internal boiler ones.

 

The system is to all intents & purposes a standard unvented sealed "wet" heating with unvented DHW tank (H.S. Megaflow)

 

I have standard radiators each with their own standard TRV (except the hallway where the internal temp sensor is).

 

The difference is the controls & sensors (as mentioned above) & that the 2-way valve to open/close the boiler flow to the rads is replaced with a 3-way valve which also takes a feed from the rads return. This now means an extra pump & a one way valve is placed after this 3-way valve on the flow to the rads. This enabling the rads to be their own pumped closed loop separate to the boiler/bypass loop or the boiler/DHW loop. You also need to lower the speed on the pump in the boiler (or in my case the one just before the boiler on the return) as its function is now just as a "shunt pump". This pumping around the boiler & DHW tank.

 

The advantage of the 3-way mixing is it can remix heat from the return from the rads, back into the flow to the rads before it gets to the boiler. This enabling many advantages in extracting maximum heat from the water & boiler control. 

 

This is beside the fact that I have an outside temp sensor & don't have to rely on an internet based "temp" as my nearest official connected weather station is 11miles away!

Edited 11 October, 20214 yr by fabdavrav

So our boiler modulates the flame/gas flow using load and return temperatures. It does have a three way valve, but no it’s not truest local external temperature compensated.

(BTW you don’t need to use the internet temperature it can use learned time to heat/cool too)

 

I know temperature compensated systems are standard in Europe, but they’re not common here.

 

What the Evohome gives me is a programmable stat in every room, where I can turn every room into a zone. Each zone/room can have its own temperature set points automatically changing 6 times a day and additional overrides. I can heat only the room I am in automatically based on times or a press of a button to override.

 

The system you describe doesn’t do that without zone valves. It will however probably be more efficient in pure gas to heat terms.

As an example the south of the house got to 28 degrees, with the north ground floor at 18 today so the need to zone the house is obvious.

 

If I was putting a system in from scratch I would have an external thermostat, and six zone valves with stats. As a cost to retrofit when it’s built as a single system with no thought to zoning this way is way cheaper.

 

I’m much more comfortable, saved a huge chunk on the gas so far and didn’t have to make any holes in the walls/floors. Total cost including 7 TRV, the controller/gateway, relay, extra remote stat and fitting was about £350.

 

Am I completely missing a point here?

 

EDIT:

 

Just put some clothes away and noticed a cable down the flue which is labelled IFOS.

A quick google suggests it may actually be an external temperature sensor on the boiler flue which the boiler uses internally.

Edited 11 October, 20214 yr by cheezemonkhai

1 hour ago, cheezemonkhai said:

So our boiler modulates the flame/gas flow using load and return temperatures. It does have a three way valve, but no it’s not truest local external temperature compensated.

(BTW you don’t need to use the internet temperature it can use learned time to heat/cool too)

 

I know temperature compensated systems are standard in Europe, but they’re not common here.

 

What the Evohome gives me is a programmable stat in every room, where I can turn every room into a zone. Each zone/room can have its own temperature set points automatically changing 6 times a day and additional overrides. I can heat only the room I am in automatically based on times or a press of a button to override.

 

The system you describe doesn’t do that without zone valves. It will however probably be more efficient in pure gas to heat terms.

As an example the south of the house got to 28 degrees, with the north ground floor at 18 today so the need to zone the house is obvious.

 

If I was putting a system in from scratch I would have an external thermostat, and six zone valves with stats. As a cost to retrofit when it’s built as a single system with no thought to zoning this way is way cheaper.

 

I’m much more comfortable, saved a huge chunk on the gas so far and didn’t have to make any holes in the walls/floors. Total cost including 7 TRV, the controller/gateway, relay, extra remote stat and fitting was about £350.

 

Am I completely missing a point here?

 

What you have is better than before. I just get annoyed as its not true weather compensating & I see loads of marketing pushing stuff which is not as efficient as old systems like mine. Especially when Europe has had this stuff for years, & its been available over here for years, (all the parts I got from my local plumbing centre).

 

You have a combi type boiler??...Your "three way valve" is instead of 2x two ways & just diverts between the rads & the internal heat exchanger for the hot water. It won't remix the flow/return to the rads as mine does as that requires 2 pumps in the system..

 

All condensing boilers ( & most others) modulate the flame/gas which is why they can state a minimum & maximum output. Usually the minimum is 1/3 of maximum...so mine is a 8kW to 24kW. (I could do with the newer 6-18kW). They do this by using the built in flow/return sensors. Even a "basic one" does this as its part of the safety controls which you get. Personally I'd prefer one without these as its "doubling" up, & my external controller can do direct fire, i.e. it has burner control output signals.

 

There are other versions of my controller which do "zones" & have solar water, & various other capabilities. With regard to the temp diff north/south..thats no problem for the other versions of mine as they have two external sensors. Mine only has one on the north side but it constantly monitor the heat loss of the building via the internal sensor..

 

Cost is the big factor as the main controller on its own is about £800.....

 

Here's a link to the current version of mine which looks identical:-

 

RVP350 - Heating controller for 1 heating circuit and d.h.w. (siemens.com)

Edited 11 October, 20214 yr by fabdavrav

Don’t get me wrong I know you can do zones on systems like yours. And that internet based temperature compensation is to the nearest area rather than my houses true value. Still better than heating regardless of the temperature in an hour/externally.
 

I was just saying I couldn’t just add it to mine as my piping would require redoing to allow for piping to appropriate zone valves. That would involve much mess and cost in a system that’s in and is likely run to minimise pipe use not allow for upgradability.

Edited 11 October, 20214 yr by cheezemonkhai