Low loss header connection Inc pump to unvented system

[damo]

I am fitting my first low loss header onto an unvented system including ufh and 300ltr tank. I have picked the job up after the ufh has been layer, tested and screened over. All I have to work with is the manifold with flow and return pipes and pre installed rad circuit all of which feed into the garage. I know how to set up the unvented system with zone valves, iso's, prvs etc but not how to and where to include the pump and how to wire it up and the arrangement of the low loss header.
Any advice would be great.
I will be installing either Worcester or viessmann.

 

[SJB060685]

Distribution header flow and return after LLH needs to be sized accordingly for mass flow rates.
Pipework for each sub circuit needs to sized correctly as well. I take it you're using a separate pump for each circuit? In which case there's no need for zone valves.
LLH can allow for air removal on top of unit and dirt separation at the bottom and thats where the EV will go in the neutral point as well.

 

[damo]

I will use separate pumps for each circuit but how to wire them in is where I will get confused!
I also don't know how much pipework is in the underfloor heating as I am finishing what another plumber has started and it's my first time working on both ufh and llh's.
The customer needs three wireless zone stats/progs for the three ufh zones and these will obviously need to trigger the pump for the ufh circuit.
I probably need to consult with the manufacturers tech rep on this one for possible schematics I think.

 

[SJB060685]

Find yourself a good electrician to help you through it.
When there's more than one pump in a system some form of relay/relays are needed to prevent back feed.

 

[Scott_D]

How big is the heating system?

 

[king of pipes]

This is the last one I did 65mm header 2m long welded connections, it sounds about the same sort of size property ? this one had 3 zones , I used a normal 2 channel programmer 1 channel hot water timing , one channel for heating timing, the 2 heating zones had programmable room stats in the the living space each circuit had its own pump and zone valve , you will need a electrian who know how to wire heating controls and install relays so each circuit can work independently of each other and fire the boiler , i used a 38kw valliant system boiler and added a extra 12 litre expansion vessel in the low loss header, i also fitted a timed secondary pump on the hotwater circuit . Good luck kop

 

[damo]

Scott d, the heating system for the rads isn't huge. There are 10 rads, all upstairs. I don't know how big the ufh circuit is? I can get square footage out of the downstairs if needed.
Kop that's very helpful and SJBO6O685 I think a good electrician is defo what I need.
Thanks gents!

 

[ShaunCorbs]

May I ask why you have decided you need a llh ?

 

[Scott_D]

A system boiler and a single heating pump may be enough.
The UFH will have its own circulator.

 

[damo]

Shaun I guess I can to my own conclusion really, based on the amount of pipework on the rad circuit and ufh although separate I just didn't want to fit the remaining system and have it struggle.

Scott the ufh has already been ran, tested and screeded by another plumber who has now left the job for health reasons and there's no pump there just a manifold .

 

[SJB060685]

I can see a pump on the UFH manifold?
As Shaun says a lot of the time a system can work perfectly fine without a LLH. LLH would be used for hydronic separation where the primary pump is not man enough to circulate around the index circuit and the addition of multiple other pumps do not all interfere with each other, it has other benefits as well ie maintaining correct flow rates and temperatures through boiler or cascade of boilers.
Unless this is an unusually large property you're likely to be able to get away with a LLH and all the wiring contained within the UFH board.