setting up underfloor heating

[the mechanic]

I had a search and a read ,it seems like many factors can influence temperatures and outputs etc etc . So having installed it myself I should have the answers ...yet here i am
asking about temperatures and control
heres what ive got :

open plan downstairs
Water ufh in calcium screed 55-60mm
over 40mm insulation
3 pipe runs 80m 80m and 53m
manifold and pump and mixing valve
3 actuators all joined into 1 zone
via heatmiser wiring center
new heat only boiler
hive 2 unit

this is what happens:

when the ufh is on it gets too hot .

mixer is set on 40c thats minimum
balance flow things are even and in the middle at about 3.5 (0 to 5)
actuators are doing who knows what ...
pump speed is on 2

eventually input manifold temp gets to almost 60c
and return manifold temp gets to 50c
thats too hot isnt it !

floor temp all be it deep within the screed rises to 35c
at about that stage the thermostat (air temp ) set on 22c finally turns off the boiler

about an hour later actual room temp has risen to 26c or more (too hot by miles)

so its over shooting and i dont know how to make it more controllable
I realise the system will respond slowly to air temp
the 75 c from the boiler seems to overcome the mixing valve over time
and temperatures go wild

thinking about it how does the wiring centre control actuators when there is no input from hive for that ? is there something missing ?

can anyone suggest levels at which things should be set at eg. pump speed, flow valves ,actuator control, boiler temperature ,
so i can get the desired 22c in the room ?
i cant seem to turn it up gradually
user error probably .

any ideas would be appreciated thanks .

 

[gassymark]

Are the flow and return to the manifold the correct way round ? Check from cold call for heat and feel the pipes. Also check mixing valve correctly fitted so circulator draws through the mixing valve.

Cheers Mark

 

[the mechanic]

cheers for the reply Mark,
I did follow the diagram that came with the unit .
My boiler flow has the zone valve on it and comes up into the bottom of the mixer
It gets hot first .
its off atm.
room temp 24c
floor about 23c
thermostat on 22c
so will be back on later trying to make it 22c , ill see what it does then i guess
[/ATTACH]

 

[Dan Robinson]

What thermostat controls that abort.... I mean... Errrm... that?

 

[the mechanic]

it helps to write it down , i think i've thunk my way to one problem , maybe?
its the actuators . they have nothing to tell them to move .so they are just open wide ON
just had new boiler put in . the old one was ...very old and only had Live earth neutral
so inside my wiring centre is a chocolate block with the basic connections to suit the old boiler ,
it wouldn't work any other way at the time
the new boiler has 2 more connections i think ? that i should be using somehow with the wiring centre.

ill need to rewire .
still not sure about whats supposed to control actuators ?

 

[the mechanic]

wiring is just stuck in there any old how atm just to try and get it ON
a few loose ends to say the least
overheat thermostat wire dangling about waiting to go somewhere ive yet to figure out .

i need a miracle . or an electrician

 

[Dan Robinson]

In the name of helping.... Post a close up of the writing on those actuators. And perhaps answer my question.

 

[Dan Robinson]

still not sure about whats supposed to control actuators

Seriously?

 

[the mechanic]

yes they are 240v if thats what your getting at ? and all i have is Hive

 

[the mechanic]

a hive thermostat measuring air temp controls the boiler

 

[Dan Robinson]

Assuming that you wired that lot up properly (this sure as *** is an installation error); are they NC actuators? Or NO?

 

[the mechanic]

they are NC

https://www.theunderfloorheatingcompany.co.uk/product/thermal-actuator-head-230v/

they are connected to the circuit board where they are supposed to go ,
they must be getting a feed as they do open .

Its amazing I've got this far ,so i accept your gasps of disbelief along with any sugestions you might have .
cheers Dan

 

[dilalio]

What other heating do you have in the property? Is it solely UFH? Or do you have rads upstairs etc?

How is your DHW supplied? Do the actuators close down when the system is fully off. Do they open when demand for DHW? If you have rads there should be separate control and stat for UFH.

 

[the mechanic]

1st hive unit switches ufh and hw zone valves
its a hw cylinder
rads upstairs thermostatic valves on zone valve with another hive for them

its a heat only boiler .

Its 3 seperate zones
s plan
Ill have to go and watch the actuators to be 100% , but they do open or stay open at least . ill get back to you later

 

[the mechanic]

they don't move , they are just open or is that closed as they are NC ? .
the return gets hot so i assumed they open . hmmm?
that's got to be one of my problems , thanks

ill need to rewire the wiring centre and see if i can get them going .