Help us understand how this UFH system works please!

[Basher]

On shining a light onto the timer, the background of the midnight to 03.30 time period is red, whilst the background for the 0500-0900 is blue. Any ideas?

The red (orange?) sector is supposed to indicate the position of the "on" cam, and the blue the "off" cam.
The link to the instructions is in post #3. It sounds like the "on" cam is actually at 5am, but I don't know why the red sector is not showing that - it might become clearer if you tried out the procedure for adjusting them.
But if not currently on an E7 tariff, the present settings might be perfectly serviceable for the moment.
A very rough bit of mental arithmetic suggests if you leave it as is, it could clock up around the monthly amount you spoke of in the first post (I could be wrong!), obviously dependent on UFH usage.

 

[whatsthenews]

The red (orange?) sector is supposed to indicate the position of the "on" cam, and the blue the "off" cam.
The link to the instructions is in post #3. It sounds like the "on" cam is actually at 5am, but I don't know why the red sector is not showing that - it might become clearer if you tried out the procedure for adjusting them.
But if not currently on an E7 tariff, the present settings might be perfectly serviceable for the moment.
A very rough bit of mental arithmetic suggests if you leave it as is, it could clock up around the monthly amount you spoke of in the first post (I could be wrong!), obviously dependent on UFH usage.

Thanks again. Yes, that's what I understood from the instructions, so I was rather baffled. As you say, if there's no E7 then it's neither here nor there.
I also came to the same calculation. You'd think the estimated bill would be based on something as I believe they've been the supplier for several years.
Gasmk1, do you have anything to add, especially since the UFH doesn't seem to have a timer?

 

[Basher]

Hi whatsthenews
I know of a UFH center like yours with the timer module fitted. I have been looking around to find the "Continental" Heatmax chrono module, but this product seems to have disappeared and the item badged with other names - the only recent equivalent has the "Watts" name.
This is what the module is like:

https://wattswater.eu/upload/iblock/f50/f50445f836482864b474c6a866499d42.pdf

and just for interest I see there's one currently on eBay:

WFHC PLUG IN TIMER UK 2368 BNIB | eBay

Find many great new & used options and get the best deals for WFHC PLUG IN TIMER UK 2368 BNIB at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Whilst this appears to be 'the right thing' I am not guaranteeing it would just plug in and work! We need someone experienced with fitting/ maintaining these to confirm different branded modules of this type can work together. I think the design is at least 10 years old - the system I've seen was installed in 2007.

It seems the industry has moved towards thermostats having time clocks in them, so different rooms can have different timings, rather than one central clock turning everything on and off (or doing setback) together.

 

[Gasmk1]

no under floor is controlled by thermostats so my advice is set them to what is comfortable other option is to change the stats to timer stats would need to see what the thermostats are to see if its feasible.

 

[Basher]

no under floor is controlled by thermostats

Sorry Gasmk1, not sure what you're saying? Individual rooms (eg zones) with hot water UFH can be controlled by ambient temp. wall stats. I have them. Did you mean it's not controlling the temperature of the water - agree it is just an on/off control of the water supply, but it does work!

 

[Gasmk1]

Sorry Gasmk1, not sure what you're saying? Individual rooms (eg zones) with hot water UFH can be controlled by ambient temp. wall stats. I have them. Did you mean it's not controlling the temperature of the water - agree it is just an on/off control of the water supply, but it does work!

You asked me if I had anything to add my answer was no,

I missed a full stop. I was saying that the stats control the heat no timer but you should be able to change them to programmable room stats. But you need to know if you want to do this as cost is involved.

 

[whatsthenews]

Hi whatsthenews
I know of a UFH center like yours with the timer module fitted. I have been looking around to find the "Continental" Heatmax chrono module, but this product seems to have disappeared and the item badged with other names - the only recent equivalent has the "Watts" name.
This is what the module is like:

https://wattswater.eu/upload/iblock/f50/f50445f836482864b474c6a866499d42.pdf

and just for interest I see there's one currently on eBay:

WFHC PLUG IN TIMER UK 2368 BNIB | eBay

Find many great new & used options and get the best deals for WFHC PLUG IN TIMER UK 2368 BNIB at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

Whilst this appears to be 'the right thing' I am not guaranteeing it would just plug in and work! We need someone experienced with fitting/ maintaining these to confirm different branded modules of this type can work together. I think the design is at least 10 years old - the system I've seen was installed in 2007.

It seems the industry has moved towards thermostats having time clocks in them, so different rooms can have different timings, rather than one central clock turning everything on and off (or doing setback) together.

Yes, I've seen that set up too and yes, seems most heating controls these days are a combined affair
I wish we knew about UFH as I'm not sure (considering the thermal store is being heated by electricity whatever we do with the stats) whether we should just leave the stats set on 19 all the time. If I have my head around it, as long as there's hot water in the tank ,apart from the electricity to run the pump, the cost is going to be the same, is it not?

no under floor is controlled by thermostats so my advice is set them to what is comfortable other option is to change the stats to timer stats would need to see what the thermostats are to see if its feasible.

the room stats are Continental Heatmax which have 3 settings.Continental Heatmax NSB dial thermostat
We've got them set on the automatic night setback mode, which is designed to set back the temp by 4c overnight, but ,if I understand correctly, this is only going to happen with the use of a timer on the UFH. (That's making the assumption that the Eco 7 is only controlling when the water tank switches on and has nothing to do with the UFH )
We're turning the room stats down to 17c overnight (still on the automatic night setback mode) and at 0800 the UFH has definitely been on and the flat is warm. To get the stat to call for heat they need to be turned up to about 21c. Slightly puzzled as to why it's so warm.

You asked me if I had anything to add my answer was no,

I missed a full stop. I was saying that the stats control the heat no timer but you should be able to change them to programmable room stats. But you need to know if you want to do this as cost is involved.

That was me who asked if there was anything else you could add.

 

[Basher]

(That's making the assumption that the Eco 7 is only controlling when the water tank switches on and has nothing to do with the UFH )

It's right to assume that the Eco 7 timer is just controlling the immersion heater(s). If the UFH chrono module had been fitted originally, then that could have controlled the immersion (eg boiler), but it wouldn't make sense to do it the other way round. The Eco 7 is only on at night, and only for a maximum period of 7 hours!
I'm not clear the night setback will even be working if the UFH chrono module is not there. When switched to setback mode, does the LED change between orange and green when you rotate the dial, and is the point at which that happens indicating about 4 deg. below ambient?

I guess there is no point in making any changes to the system if it is providing adequate heating. If certain rooms are not required to be heated at certain times, it might be worth putting in a programmer (or changing the thermostats) but the saving in electricity would take a while to pay back the expenditure!

 

[whatsthenews]

It's right to assume that the Eco 7 timer is just controlling the immersion heater(s). If the UFH chrono module had been fitted originally, then that could have controlled the immersion (eg boiler), but it wouldn't make sense to do it the other way round. The Eco 7 is only on at night, and only for a maximum period of 7 hours!
I'm not clear the night setback will even be working if the UFH chrono module is not there. When switched to setback mode, does the LED change between orange and green when you rotate the dial, and is the point at which that happens indicating about 4 deg. below ambient?

I guess there is no point in making any changes to the system if it is providing adequate heating. If certain rooms are not required to be heated at certain times, it might be worth putting in a programmer (or changing the thermostats) but the saving in electricity would take a while to pay back the expenditure!

Thanks Basher.
That's what I thought. Spoken to a couple of residents who say they don't have an Eco 7 meter. Presumably the system was set up to be used with Eco 7, so not sure why it's not. Looking at various Eco 7 tariffs, night time unit rates are around 9p, compared to about 14p for standard tariffs. I have no idea how a meter works, especially when it's remote to the consumer unit.
Also agree that the nightime set back won't work. The only LED colour we seem to get on the stat is red.
On closer inspection of the Eco 7 timer, I can see the red "on" tab and the blue "off" tab in the windows.
Red is at about 0200 and blue around 07.30.
Would I be correct in assuming that the immersion has a thermostat so it'll switch off independent of the timer when the water reaches the set temperature?
I still don't fully understand how the UFH manifold works regarding flow and return.
Is there a loop that circulates just through the UF pipes and the 2 sides of the manifold, with the mixer valve (there's a motorised valve) opening to add hot water from the thermal store ie the HW tank) to keep it at the set temp'? As opposed to a bigger loop where the returning water goes into the HW tank and then flows back out around the whole system? Hope that makes sense!

 

[Basher]

I have no idea how a meter works, especially when it's remote to the consumer unit.

These days one can have a dual tariff smart meter, which feeds the same electricity up the same wires, but just records what you use during the defined night time period on one totaliser, and what you use during the day on another, and keeps tabs on the total. Slight problem is that although the night rate is much cheaper, in many cases the day rate is a bit more expensive. So the savings might not be as great as you would think if you need lots of daytime electricity. The heat store is a great candidate for dual rate, but depends what happens during the day.

You may have already had a look at background material on UFH, eg

Underfloor heating explained

Underfloor heating can seem complicated at first but once you know the basics you will see how beneficial it can be. Use this page to understand the basics

www.johnguest.com

I confess my background is electrics, not plumbing. What I don't understand is that the heat store appears to have only one coil, which takes incoming mains pressure cold water, heats it and feeds it to the taps. Apparently the UFH is connected to the same coil. Surely that means that water from your hot taps could be mixed with that running through the UFH pipes, unless there is some sort of hydraulic separation somewhere. It doesn't seem a very hygenic arrangement. I would be interested to hear others observations.
Sorry to ask again, but are you absolutely sure the UFH stops working if you turn the E7 off completely?
(probably not an experiment to do at this time of the year). The presence of the energy monitor is still bothering me