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Discuss Low loss header connection Inc pump to unvented system in the Plumbing Forum | Plumbing Advice area at PlumbersForums.net

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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.
 
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.
 
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.
 
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.
 
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
 

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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!
 
May I ask why you have decided you need a llh ?
 
A system boiler and a single heating pump may be enough.
The UFH will have its own circulator.
 
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 .
 

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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.
 
Yes of course there's a pump on it. Need to check my own pics. Sorry its one of those days. I visited the job a week ago now so its not fresh in my head. Its a detached 4 bed dorma bungalow so the upstairs footprint is smaller than the downstairs so no it's not unusually large mate.
Probs best leaving the llh out of it and uncomplicate the situation .
Thanks again
 
Tbh I wouldn’t bother at most close tee the ufh and then just install one pump 15-60 should be good enough or sys boiler

pumps on the left hand side of the manifold?
 
Yeah I think I am going to hopefully go with a viessmann 2 pipe system boiler and zone valve the the 3 circuits. A 4 pipe vitodens will be no good for my needs I don't think.
 
Depends if the pipe work is already there or if you can get direct to the cylinder

It’s a good set up
 
The only pipework in the property is the ufh circuits, the flow and return from the garage to the ufh manifold, the cold mains feed into the garage, the upstairs rad circuit flew and return hanging down in the garage and the feed to the the hot taps from the garage! All unconnected and ready for the boiler, cylinder, copper pipework, zone valves ex vessels to be sourced and installed..... oh and all the electrical stuff.
Basically blank canvas!
 
I would 4 pipe it faster hot water re heat times have a word with Viessmann’s
 
I did one similar recently a tight install in a utility room so as Shaun said I 4 piped it, have a look at oso unvented cylinders all connections are on the top so makes a clean tidy install .
 

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Kop that's a very smart set!
I think the customer wants all Worcester or viessman tho. Much swing them across to vaillant as they are a very tidy boiler on the inside.
All you lads advice is appreciated.
If yous weren't so far away I would propose a job share to gain the experience from any of you.
What was the labour on that one roughly kop if you don't mind me asking?
 
I wouldn't fit eithier mate i hate plastic hydroblocks , valliant is hard to beat what you see there was 2k labour theres alot of pipework behind that wall and a cloak room gas supply in 28mm gas tite pipe . Kop
 
I would go Viessmann’s depending on budget 200 series
 
I did one similar recently a tight install in a utility room so as Shaun said I 4 piped it, have a look at oso unvented cylinders all connections are on the top so makes a clean tidy install .
Do you think the 4 pipe setup saves enough time/materials to cover the extra expense of the boiler?
 
I designed it all mate but my customer was insistent on a Valliant so went with it, i guided them towards the oso cylinder though for ease of fitting . 😉
 

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