Underfloor heating when the manifold is far away from the boiler

[DynamicC]

Hi all,

I am planning on doing a wet DIY underfloor heating install downstairs of my property.

I have zero experience with the plumbing and electrics side of the install, I plan to get a pro in to hook everything up but want to ask a question to make sure I have not missed anything prior to their visit.

I have attached a diagram of what I think in my head is correct, but open to suggestions here. ( complete novice )

I have radiators upstairs for now and plan to do an underfloor system when I renovate the upstairs of the property.

I plan to have 2 nest thermostats, one upstairs and one down stairs ( its a small open plan property )

The upstairs makes sense to me, the Nest Link will tell the 2 way valve to open which will also tell the boiler to switch on.

However the down stairs is confusing me, the Nest will tell the 2 way valve to turn on, which will tell the boiler to turn on but what tells the underfloor pump to switch on.
Ideally I am trying to avoid running a cable to the boiler as the boiler is in the loft space and will be a royal pain.

Any advice would be much appreciated.
Many thanks

[Dave Jones]

dont bother with multiple stats upstairs.

 

one underfloor loop (no room stats).

 

How much insulation you putting under the floor screed ?

 

 

[DynamicC]

2 minutes ago, Dave Jones said:

dont bother with multiple stats upstairs.

 

one underfloor loop (no room stats).

 

How much insulation you putting under the floor screed ?

 

 

I was only planing on using one stat upstairs and one down stairs, would this be adequate?

I am planing on using a "dry" install system, something like Omnie LowBoard unless someone else has better suggestions in the UK. 

[Nickfromwales]

You can get a wireless relay, but you’d need one that sends an on then am off signal ( flip flop ).

Check with the various big names to see what they offer. Oh, and avoid Honeywell EvoHome like the plague. Unreliable bag of 💩.

 

Order of events;

 

Room stat sends call for heat signal to manifold wiring centre. 
 

Wiring centre opens the actuators for that zone. Then sends power to the manifold pump and closes a relay on board which goes to the 2-port valve brown wire. 
 

Motorised valve opens over around 8-10 seconds and closes its integral micro switch once 100% of travel has been achieved ( eg valve is fully open ). 
 

Orange and grey wires of the motorised valve ( out of the 5 cores ) get connected together by the micro switch. 
 

That gives you the control that tells the boiler to fire. You either keep those volt-free, or feed with 230v and send whichever ( via a cable ) to the boiler call for heat terminals.

[Nickfromwales]

1 minute ago, DynamicC said:

I was only planing on using one stat upstairs and one down stairs, would this be adequate?

I am planing on using a "dry" install system, something like Omnie LowBoard unless someone else has better suggestions in the UK. 

Usually better to have individual room controls for each bedroom, so the ones in use can have setback temps and lesser used rooms can be mothballed at lower set temps.

One stat for all upper floor rooms can be quite indiscriminate, particularly if one bedroom is south facing and another to the north. Very different needs then.  

[Dave Jones]

10 minutes ago, DynamicC said:

I was only planing on using one stat upstairs and one down stairs, would this be adequate?

I am planing on using a "dry" install system, something like Omnie LowBoard unless someone else has better suggestions in the UK. 

 

 

if you dont have any insulation in the slab you will be wasting ££££ in heating .