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Hogey

Wet underfloor heating control problem

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Hogey

Hi Guys

 

Just seeing if anyone can help out an issue I have on a job. The plumbers have installed two wet underfloor heating zones which both have there own thermostats. At the manifold they have fitted two motorized valves, one for the central heating in the house and the other to cover the two underfloor heating. The customers boiler is wired into a basic time clock and he controls the heat via the boiler's controls. I've been supplied a Heatmiser UH4 so for his central heating I have wired the time clock into the first stat and wired the brown and blue cable from the first motorized valve into the actuator L & N. This works fine for how the customer would like it however I'm having trouble working out how to wire the other motorized valve. As there's two zones with two stats I'm not sure how I'm to wire the one motorized value across two zones, is it possible? I've tried to attach a couple pictures of the instillation that I've took, hope you can make them out, any help would be much appreciated. Cheers. 

 

https://www.google.co.uk/search?tbs=sbi:AMhZZivU8nymdcYBdbrvLpV4SKt5QZ0jSYIOKBMJ9PsSCUIGUxZZ-1pKgCQcYrlkaV37aKeA9pU38Edos0pwjIxjGZmzu27iGk4VjecDI9YRubH-mh1DByQ-wgembXOsUKIitrBkVCymSuT1RE-bUFo9OMTtRhKGJT9tGzBTHW472BCcICCE9kp0f-4yylF5Ea9bHkp-wpwU311azsn9eRkEmj4HmC63t8BJk7ZiAdfuvF0-3nRa18xAUZexgTnyi2MoGsaajjcNL49bbsbwc1ezBY7teGYdZ747uo09Yd2F2HMvobPM6R1i_1vLg6zgRmQM1j0Xnuh-Q&hl=en-GB

 

https://www.google.co.uk/search?tbs=sbi:AMhZZis3VngU7qJY5pF5kovBFpf89kn7YJSGpf1Fj-qK_1tnSxvGBTtsZSG5rnADzxBRYuMZK0-XgFhMAKEL-xPOvaa2Ih9B8uYkQvNYyzbYfHoif2xzDIPSm0lUCdeEhvtOkCmn9oFO5BKlXIfrJnDLP5Fvx50qZ3ihn_12eBFvH65jGsEE0po31GZ7NtWgH9lQnBVw2S2O178iUEFBmyXwVOtoRulWYMu9YAv603t442woHWCxn3bWbTkYs-zoSy9D-JZv7axByHGQNCLTkKL34rglb9Z-Onb8PJSTGh4J4oLEmxuq_1E3naFu2V2xQ9Gtr97uaIaxUyi&hl=en-GB

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poni

I cant get the link to work, but if I understand it right 

you have two valves and two stats

is not one stat for the whole house and the other stat for the underfloor heating ?

 

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Hogey

Thanks for your reply Poni. No sorry that's not right, there's a time clock for the central heating which is wired in with one of the motorized valves and then two separate stats for the two underfloor heating zones. I'll see if I can figure out how to upload a pic properly 🙈 I need a technology for dummies book 😂

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Geoff1946

I can't make anything of your links, but your description doesn't really read correctly. If there are to be two underfloor zones on their own area stats then there must also be two motorised valves; one per zone..

The underfloor systems (that I've met) work at a low temperature and mix hot water from the central heating system with return water from the underfloor pipes. They have their own pump to do this and are therefore largely independent from any "normal" central heating system in the house. It will obviously be necessary to send a heat demand signal.

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Murdoch

If you want to control :

 

1. Radiators with its own room stat

2. Underfloor area 1 - with room stat

2. Underfloor area 2 - with room stat

 

That will work with 2 motorised valves, but you will need to set up the UFH manifold so the UFH room stats control the output to the areas accordingly ..............

Edited by Murdoch

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Geoff1946
24 minutes ago, Murdoch said:

l need to set up the UFH manifold so the UFH room stats control the output to the areas accordingly ..............

Ah, that suggests an "intelligent" manifold.   That's outside my experience; the only manifolds I've seen were totally passive.

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ProDave

Okay here are the basics (you seem to fundamentally not understanding how it works)

 

Time clock output to feed the power in the the UH4 for the UFH.

 

Room thermostats for each UFH zone directly connect to the UH4.  there are 4 available zones on a UH4 you will be using two of them.

 

the UH4 has outputs to power the UFH manifold pump and individual outputs to power each of the actuator heads one for each pipe loop and each heating zone may switch more than one pipe loop.

 

The UH4 also has a switched 240V "call for heat" output.  THIS powers the 2 port motorised valve for the UFH.

 

The switch contacts (orange and grey) on the 2 port motorised valves fire the boiler.

 

If you have a radiator circuit as well then That time switch output via any room thermostat for the radiator zone activates the radiator circuit motorised valve.  The switch contacts from that connect in parallel to the switch contacts from the UFH motorised valve so either motorised valve opening calls for heat from the boiler.

 

It is best with UFH to have different time settings to the radiators.  the Horstman 3 channel programmer is particularly good for this.

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Hogey

Hi Guys, thanks for your messages. I think I've worked out the picture situation so I can show you the set up.

 

https://ibb.co/SNm2Pvb

 

https://ibb.co/6RPVdPG

 

https://ibb.co/VmS25BG

 

As the customer just has a basic time clock switch the CH on during the day, I have that wired into the UH4 at the first zone and the first motorized valve wired bellow using just the brown and blue which works fine. You may suggest that's not right though. I don't seem to have a 'call for heat' output though as ProDave suggested and that would make sense so I'm a little puzzled how I'd split one valve across two UH4 zones. Any more advice would be appreciated. Thanks.

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Murdoch
22 minutes ago, Hogey said:

I'm a little puzzled how I'd split one valve across two UH4 zones. Any more advice would be appreciated. Thanks.

 

Have you read the instructions for the UH4?

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ProDave
1 hour ago, Hogey said:

Hi Guys, thanks for your messages. I think I've worked out the picture situation so I can show you the set up.

 

https://ibb.co/SNm2Pvb

 

https://ibb.co/6RPVdPG

 

https://ibb.co/VmS25BG

 

As the customer just has a basic time clock switch the CH on during the day, I have that wired into the UH4 at the first zone and the first motorized valve wired bellow using just the brown and blue which works fine. You may suggest that's not right though. I don't seem to have a 'call for heat' output though as ProDave suggested and that would make sense so I'm a little puzzled how I'd split one valve across two UH4 zones. Any more advice would be appreciated. Thanks.

Read the manual.  As I tried to explain you do NOT connect the time switch to a thermostat input and you do NOT use zone 1 to control the motorised valve.

 

Zones 1 to 4 are the 4 under floor heating zones, which typically means 4 rooms as it is normal with UFH to have a room thermostat in every room.

 

So Zone 1 thermostat is room 1 thermostat, and zone 1 actuators are the valve heads on the manifold that feed the UFH pipes in room 1.  there may be typically anything from 1 to 4 pipe loops per room depending on the room size.

 

The time clock feeds the POWER input to the UH4

 

There is a dedicated call for heat output, I forget exactly what it is called on the UH4. that is what energises the motorised valve.  The logic within the UH4 will energise the motorised valve when power is on (time clock says I want heating) AND when ANY room is calling for heat from it's thermostat.

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Murdoch

And may I add, please don’t do what lots of people do and have a separate mains feed for the underfloor heating controller, not only is it dangerous, it also really annoys the plumber ... / GSR

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