Honeywell Evohome experts advise sought

[rillenkarren]

hi, i am seeking advice on the configuration of the wireless evohome system to an existing UFH installation.What i need to know is how precisely could i configure such a system and which individual components would be required. I raised a general thread and in this my requirements and current installation details are described. If anyone can offer specific advise it would be greatly appreciated.

//www.diynot.com/diy/threads/underfloor-heating-control.449881/

 

[Dan Robinson]

You need someone on site really.

Have given you two options that would work one with no local mains power needed (but might not fit) and one that will fit, but needs mains power.

@simond and myself are probably as expert as you can get with this stuff in the domestic environment on this forum, although there are a few others that are very good.


Option 1 -

HR92's for each circuit with a remote sensor (DT92e, HCF82, HCW82, T87 are the options). Evohome can be the sensor in one zone.

No power required, except for the base unit.


Option 2 -

Hcc80, with the required number of UFH actuators for the circuits. Honeywell have the MT4. The HCC comes equipped for 5 control zones - you can add a further 3 with an expansion card.

Then, as above, you need sensors for each control zone. Evohome can act as one.

Mains power is needed for the HCC and the Evo unit.



In all cases, multiple actuators can be assigned to a zone. So if the living area has three loops, that is not a problem.

 

[simond]

Ironically, Hometronic, the predecessor to Evohome, was designed and developed in Germany specifically for this application, because 'district heating' is far more common and German householders commonly complained there was no control. It had to be modified late in development to add boiler control for other markets like here.

This system pictured is unusual because it all must be low temperature, unless the heating pipes are in the walls or ceiling. Or they may be copper because they can't be certain of accurate pressure regulation in a large building with multiple floors.

You need to be careful with the HCC underfloor controller because it is only designed with a very modest current switching capacity, I think 3 heads are the maximum per zone, and I think there's a maximum no of thermal actuators per manifold. We've had to use relays in the past to put multiple pipe loops on a zone (you can't currently link two zones on an HCC to one thermostat in software).

So I would go with Dan's suggestion 2, especially as with separate BDR relays you would need to space them 300mm apart for reliable operation and that would probably look a mess.

I don't think Option 1 would be such a good plan because the HR92s are bidirectional RF and would end up very close together. Evohome is a bit touchy about siting 2 or more RF TX/RX devices very close together.

 

[Dan Robinson]

3 heads are the maximum per zone

Zone 1has three gates, Zone 2 has 2, the rest are single, however, it does say in the destructions you can common them up remotely - then elsewhere, that the limit on the controller is 11. I have pushed 4 on zone 1 without problems with 12 in total.

you can't currently link two zones on an HCC to one thermostat in software

Yes you can bud - my Ground floor was originally two zones, but I merged them. Have a T87 driving both, but zones 1 and 2 are bound in as one.

I don't think Option 1 would be such a good plan because the HR92s are bidirectional RF and would end up very close together. Evohome is a bit touchy about siting 2

Very true at least in the binding phase... again, I have got two sitting next to each other on a manifold quite happily. Although to one is an HR82 and the other an HR92. I bound them in away from the manifold with a nice gap betwixt them.


I too prefer option 2 though. Much less to go wrong, and only one cable to sort out if the heads are too tall to fit inside.

 

[simond]

Funny that, Honeywell (RW) assured me you couldn't bind two outputs on the HCC to one stat. Not the first time he's been wrong. How did you do it, cause the Evo doesn't give an option for further actuators on an HCC in the binding process?

If you look at the current draw allowance on the HCC, you will see that 3 thermal heads takes it to the edge. We've always been told that, long before RW.

 

[Dan Robinson]

Funnily enough it was RW that told me how to merge the zones... Bear in mind I'm running the old firmware of the HCC.

When I bind in the zone, and you press the button on the HCC, you get the green light. Press the button again to move onto the next zone, but press back on the base station. then bind in again.

Voila. Two zones come on based on a single thermostat.

Now, I have not tried that on the latest firmware release.

 

[Dan Robinson]

Mind you - at the moment those two zones are also operating as one on an HM80

Although it is coming out again next week.

 

[simond]

Ah, that is cunning, going back again....... must try that.

 

[Dan Robinson]

It was a source of mild surprise.... but it had been an emotional week, and I was half cut when i did the binding.

Double vision when trying to bind a DT92e in a cold garage sitting on an upturned bucket isn't a recommended environment for binding a mix of UFH and rads through an HCC80. Especially on the old firmware . That was the one that had to be bound to Evo twice anyway.

So merging zones meant 4 times in total. Making my head hurt now just thinking about

 

[Dan Robinson]

Thinking about it - RW might not have told me after all - it could have been the beer pixies.


Either way - they were right and I should listen to them/him again in future.

 

[rillenkarren]

hello Dan, sorry but I understood that you could not answer all of my questions but now you have answered them albeit in a different thread !
my personal preference would be for option 1 because its cheaper, does not require mains and I feel i could do it myself.
The only issue is the depth of the case, that i need to measure precisely.

I only really have two zones that i want to control, the living area (consisting of three circuits) and bathroom 1 circuit, i don't heat the other rooms.
so for option 1 for these two rooms i would need the following:

1. control panel EAN-5025121382083 (integral room sensor for living room)
2. 4x HR92 EAN-5025121382069
3. desk mounted control panel holder EAN-5025121385428
4. 1 DT92e (for bathroom)

As the actuators will be sited in a complete metal box, do you imagine this would cause issues with RF tx/rx ?
Actually now I appear to have a more serious problem, the valves are all on 50mm centres, the HR92s are are 54mm wide.
I suppose there is no reason why the positions on the manifold cant be changed to offset the units, but looks like its a job for the CH people.

 

[Dan Robinson]

1 DT92e (for bathroom)

These are not rated for wet environments, but having said that I have one in my bathroom as a test to see how long it lasts.

On Friday I am fitting a system for a client whereby I have to use a sensor in a wetroom. Fir this we have adapted a HCF82 to be water proof (ish).


The HCC80 has a big antenna in it - and I believe in the continent you can get an additional antenna for it as an accessory.

Mains supply notwithstanding you only have a couple of hours work for option 2 for a professional. Look on the Honeywell website in your country and they should have a list of installers and specialists.

I would suggest a specialist is better as you are not a typical installation - albeit not complicated.