mixer value on underfloor heating?

[grandfortune]

HI all,

installed a s plan, well i say s plan, heating up stairs and underfloor down,

there is a 3 way manifold for the underfloor heating, a couple of question regarding that pls

1 actuator came , but there is a value i open with that stat so i assume i dont need the actuator ??

also i think the underfloor stops as regards to the mixer value, plumber says if the water is upto temperature the water will stop going though, is this right?

as i want the stat to control the underfloor only, and it looks like the mixer value is overriding if you know what i mean.

what are these mixer valves for?

cheers
Grand

 

[Leesparkykent]

UFH has a low Flow temperature requirement so the blending valve mixes the flow from the boiler with the return water of the UFH at the manifold position so you get the correct temperature of water flowing through the UFH loops. Do you have multiple thermostats on the UFH or Is it all controlled by one thermostat?

 

[grandfortune]

one stat m8, before i wired it i temp did it on constant, it kept cutting out so when we moved the mixer value up it stated kicking in again, it seems stragnge that the mixer value works as kind of a stat so it seems. its all wired properly now ( no actualtors) but have been told by the builder that its not getting that hot in there, before i go i thought id post here, but im assuming it will be that mixer value again and the plumber has turned it down. but i am guessing here.

 

[sean_ork]

also i think the underfloor stops as regards to the mixer value, plumber says if the water is upto temperature the water will stop going though, is this right?

as i want the stat to control the underfloor only, and it looks like the mixer value is overriding if you know what i mean.

What make manifold is it ?

The mixer valve is usually a manually set mechanical valve that allows you to set the temp of the water circulating within the loops, as above it just mixes mains cold with the returned hot - usually set to not much more that 40 degrees, and its only set once - the room stat is used to set the air temp.

Most manifolds have an overheat stat which stops the pump if it sees overtemp, that might be what's making the plumber think the mixer shuts when it's up to temp.

As with all systems like this theres numerous ways to wire it - you could have all loops and their actuators on their own stats - if you've got 3 loops and just one actuator are you sure there's flow on all loops ? - there should be flow sights on each loops (on the manifold)

A cold stone cold slab will likely take 5 - 8 hours to show a temperature rise, especially if the loop spacings are wide - and it'll obvioulsy never all get warm unless there's flow to all loops.

Find out what make manifold it is, at least then you'll be able to figure out what the system is supposed to be doing, no point trying to fault find until you know how it should work.

 

[Leesparkykent]

one stat m8, before i wired it i temp did it on constant, it kept cutting out so when we moved the mixer value up it stated kicking in again, it seems stragnge that the mixer value works as kind of a stat so it seems. its all wired properly now ( no actualtors) but have been told by the builder that its not getting that hot in there, before i go i thought id post here, but im assuming it will be that mixer value again and the plumber has turned it down. but i am guessing here.

I'd think possibly a plumbing issue...mixing valve isn't set to the correct temp or maybe he hasn't balanced the ufh properly by adjusting the flow rate to get the most out of the system. Also if the plumber hasn't fully got the air out then possibly the return is getting hot really quick and locking the boiler out. I'm pretty sure the plumber is talking wet though about the mixing valve