Verify this installation

[squishio]

Hi All,

I'd like some advise regarding the installation of my boiler. Specifically the close coupled tee arangement to hookup the underfloor heating.
The boiler is currently in the loft, and is shortly moving to the ground floor.
The installation was completed by an engineer I very much trust, but he's too busy/doesnt want to travel (60miles) to me to move the boiler, so am having someone else who I also trust, but doesn't fully understand the installation, he's a bit old school, but is happy to move it "as is" to avoid any changes, and yes, he's registered.

I've had two other local engineers attend who have both slagged off the installation, but I think this is through lack of understanding. I know its not a pretty installation, it was done in the dark in an unboarded loft at the time. Once moved it can be repiped and look pretty. Which leads me onto part two of the question, attached is a diagram of how I think it would most practical to route pipework based on the new location, can anyone spot any faults with this.
The system has been in as is for about 2 years and has worked perfectly.

So...
#1 Can anyone see anything wrong with the installation as is?
#2 Can anyone see anything wrong with the drawing of how it will be?
#3 Any improvements/adjustment that could/should be made?

One bit not on the drawing, I intend to add another magnaclean or similar to the return rad feed to protect the UFH from any crap that comes from the rads.

Other details...

Boiler - Vailant EcoTec 837 Plus
Thermostat - VRC470F
Radiators - 5
UFH Loops - 4
UFH Total Area ~90SQM
UFH temp control is via flow temp sensor into the wiring centre, configured on the stat as "Heating Circuit 2", rads are on circuit 1.

Hope thats all thats required?!

Thanks in advance!

 

[Harvest Fields]

Why are all your flows and returns in the flow? Do you only have one return? Do any of your circuits work?

 

[squishio]

Yes, everything works perfectly at present.

The easiest way I can think of describing it is the UFH and rads pull hot water from a constantly circulating loop as and when there is a demand for heat in their zone.
Pump integral to the boiler keeps the water looping, rad and UFH pumps pull off that loop and return to it.
That is at least my understanding, but I'm not a heating engineer...

 

[Aire]

Well that's just a complete mess isn't it.

 

[Stu-B]

Well that's just a complete mess isn't it.

That’s just through lack of understanding, same as the other 2 local guys

 

[Aire]

That’s just through lack of understanding, same as the other 2 local guys

I can see why his usual trusted engineer is too busy to move the boiler

 

[squishio]

If it helps anyones understanding of whats going on, the close coupled tee arrangement was to avoid/an alternative to using a Vailant low loss header.

Which going off this diagram, looks rather similar to whats going on in my install?

Open to comments though preferably constructive / help my understanding

 

[Aire]

Why find an alternative to using a low loss header? And what your trusted engineer did was not an alternative to a low loss header, it's just a poor install, it's piped up wrong. To be honest it looks more like a diy install by someone with limited knowledge of heating systems. If it was me, I'd strip it out and start again, and that's not because I don't understand your system, it's because I know it's wrong.

 

[squishio]

Why find an alternative? Because a LLH from Vaillant is £200+ whereas a few tees cost a tenner and appear to achieve largely the same thing?

There seems to be quite a few threads on here where people have discussed close tees vs LLH before, though from what I'm reading, perhaps its not common practice in the UK?

I dont in anyway intend to insult or disregard any advice given here, you're the professionals after all, just what I'm reading matches up with what I've got.

Craig, you know its wrong, but what exactly about it is wrong? (ignoring the abomination of the layour and pushfit plastic!)

 

[Aire]

Why find an alternative? Because a LLH from Vaillant is £200+ whereas a few tees cost a tenner and appear to achieve largely the same thing?

There seems to be quite a few threads on here where people have discussed close tees vs LLH before, though from what I'm reading, perhaps its not common practice in the UK?

I dont in anyway intend to insult or disregard any advice given here, you're the professionals after all, just what I'm reading matches up with what I've got.

Craig, you know its wrong, but what exactly about it is wrong? (ignoring the abomination of the layour and pushfit plastic!)

Ok I'll back track a little, I've read into how close spaced tees work and they do appear to be a cost effective form of hydraulic separation, and while your system is a visual mess, it does look correct.

 

[Harvest Fields]

Never understood close couples tees. Just buy a LLH non of the messing around.

 

[quality]

Ive seen worse but looks functional. Is that an esbe valve on the ufh?

 

[ShaunCorbs]

its not the best and could of been done alot neater and eiaser to understand / service

for example why is the rads return so close to the boiler outlet flow (dont need to cct your rads circuits)

also your suppose to up size your cct eg 22mm primarys 28mm ccts etc

sorry to say this is where a bit of knowledge is bad without understanding it totally

the reason you want ccts on ufh (unless your boiler can modulate down) is to keep your boiler from cycling too much

surprised you didnt go with the vaillant mixing station

 

[squishio]

So, it could be beneficial to up the header loop to 28mm reducing to 22mm at each tee off point?

I wasnt aware of a Vaillant mixing station, cant find much on google, what is one/what does it do (beyond whats in the name!)

I'm not sure what ESBE stands for, but its an electronic mixing valve (Honeywell) controlled by the VR61, mixing the UFH to the correct flow temp monitored also by the VR61 using a sensor strapped to the pipe.

Onto my (amazing) hand drawn diagram, does it make sense to be re done as I've shown? Hopefully making things clearer/neater.

Another related question, though I imagine the engineer coming to move it can answer, doesnt hurt to have others answers too, there is a soil stack adjacent (3ft) to where the boiler is moving do, this is where the condensate will run, am I correct in understanding the PRV pipe can run down (300mm min?) to a tundish and then thats piped also to the soil stack?
If thats right, would it be plastic or copper from the tundish to the stack?
Just trying to work out placement of other utilities/services in the new location.

Thanks guys!

 

[squishio]

oh, and on the topic of modulation, if it has any bearing on this, the boiler is turned down to 7kW, i think, last time I looked.

 

[ShaunCorbs]

See where the cc tee is on my pic

Top bottom outlet reduces down to 28mm

The tees are 35mm

 

[Harvest Fields]

See where the cc tee is on my pic

Top bottom outlet reduces down to 28mm

The tees are 35mm

Nice and neat that is mate.

 

[ShaunCorbs]

So, it could be beneficial to up the header loop to 28mm reducing to 22mm at each tee off point?

I wasnt aware of a Vaillant mixing station, cant find much on google, what is one/what does it do (beyond whats in the name!)

I'm not sure what ESBE stands for, but its an electronic mixing valve (Honeywell) controlled by the VR61, mixing the UFH to the correct flow temp monitored also by the VR61 using a sensor strapped to the pipe.

Onto my (amazing) hand drawn diagram, does it make sense to be re done as I've shown? Hopefully making things clearer/neater.

Another related question, though I imagine the engineer coming to move it can answer, doesnt hurt to have others answers too, there is a soil stack adjacent (3ft) to where the boiler is moving do, this is where the condensate will run, am I correct in understanding the PRV pipe can run down (300mm min?) to a tundish and then thats piped also to the soil stack?
If thats right, would it be plastic or copper from the tundish to the stack?
Just trying to work out placement of other utilities/services in the new location.

Thanks guys!

you can get them mixed or un mixed

VDM 10 with circulation pump Wilo Yonos Para

The pumping group with a circulation pump Wilo Yonos Para with electronic adjustment and pressure up to 6 m, is designed to support the required flow rate of coolant in the circuit.

www.iqenergy.org.ua

example (not mine)

 

[Riley]

I may be picking this up someway along but be honest is this diy??

 

[Brambles]

You asked for advice.

Before you consider doing anything with that system, I would accurately map out the existing system then redesign (from a hydraulic perspective) the pipework to get a “best fit”. The sketch you provided with your photos appears to show the heating return feeding back into the flow. Why is there an external heating pump - how is this configured to run with the integral pump?

The mixing station should be as close as possible to the manifold(s) not remote

I would reflect on the advice that the two installers gave you, they probably had some valid points

 

[doitmyself]

I'd like some advise regarding the installation of my boiler. Specifically the close coupled tee arangement to hookup the underfloor heating.

If the installers are not familiar with Primary/Secondary piping using closely spaced Tees, there are some rules which they need to follow. The first diagram should explain everything.

A second factor to consider is water temperature. As piped, with the underfloor pair after the radiator pair, the flow temperature to the underfloor pair will vary depending on how much is taken by the rad circuit. So it could vary between, say, 70C and 50C which is reasonable as UF needs a temperature of about 50C, or less. But you have a thermostat which uses weather compensation to determine the flow temperature. So while the flow temperature to the rads may be OK there is a danger that the flow to the UF circuit could be too low. The way to overcome this is to have the radiator and UF circuits in parallel and not in series. They are then both fed the same temperature water. See the second diagram.

 

[doitmyself]

See where the cc tee is on my pic

Sorry, but I can't see a pair of CC tees anywhere.

 

[squishio]

@Brambles Why is it the mixer should be close to the manifold?
As it stands at the moment (not saying its right!) the mixer is in the loft, and the manifold is two floor down.

@doitmyself That is very helpful, thankyou. I'll re-do my diagram to reflect what you've drawn. Out of interest, what is the relevance of the distance between tees? If you're pulling from one and putting it back in the other, what does the distance between them have to do with it?

 

[ShaunCorbs]

Max 4x the dia of the supply pipe eg 22mm 88mm

 

[squishio]

Max 4x the dia of the supply pipe eg 22mm 88mm

I got that bit, but why does that seperation matter? ie why couldnt it be 12" between the tees?
Or am I asking questions that dont need asking

 

[ShaunCorbs]

I got that bit, but why does that seperation matter? ie why couldnt it be 12" between the tees?
Or am I asking questions that dont need asking

Would be too far apart to work efficiently

 

[doitmyself]

what is the relevance of the distance between tees? If you're pulling from one and putting it back in the other, what does the distance between them have to do with it?

It's all to do with the pressure difference between the flow and return ports. This needs to be as small as possible. If it's too big the water may prefer to travel straight past the port, depriving the rads of any flow..

The distance from ports to any bend (or Tee in a parallel system) in the primary circuit is to reduce turbulence in the flow.