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Aug 13, 2015
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Afternoon all

After getting to a point where i am almost ready for my new boiler system to be fitted. I am going for either a Viessmann or unvented but i think swaying towards the unvented due to hot water contingency if the boiler goes down (too many stories of people waiting days for parts, taking cold showers!). I have rigged the system to be easily converted to two zones for CH, S plan (currently one loop, S plan), obvious hot water and possibly a single water underfloor being added eventually.

My original intention was to go with NEST gen 3 x2, one for each zone and the lower zone controlling the hot water. This is a medium sized 4 bed detached property, so nothing worryingly huge.

Yesterday i took the time to contact a really helpful chap enquiring about Evo Home which I can see is a far superior system, especially when linked to Opentherm! My problem is the usual cost associated given that I have 11 rads, 2 of which (designer) have nice shiny new valves which won't be Evo compatible and are quite prominent (kitchen/Hall).

This got me thinking about the benefits of Opentherm and upon reading, it sounds daft to ignore it. My problem is this though - from what i understand you cannot have duel NESTS on Opentherm as it understandably can only be controlled from one source, so is my only solution to stay with one ring? Maintaining what is in place now..... if i want to use Opentherm....

Possibly going to a single ring on Honeywell connect, using Opentherm bridge, hot water bridge - meaning i'll be opentherm from day one and able to add the TRV therms once i am able to afford (might need a second job just to pay for 11 of those :/)
 
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Update! I'm fully wired up and the system is working. So far it's only been a day but I am highly impressed. Just need to refine the schedule to suit our comings and goings.

I have replaced one of the heads for our en suite with a manual one for now as I don't have a relief valve fitted... Set this at 2 out of 5, so hopefully that will protect it until the new system goes in.

Thanks for everyone's help on this, notably Rob and Shaun... Thanks chaps
 
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It soon learns the rooms, at first mine all overshot the temps, now it knows when to switch off to hit the target. For the living room set to go off at 20:00 it is turning off around 19:00 now.
When it has the rooms up to temp the boiler is still cycling a bit but the flow is only around 32c.
Maybe when the whole house is falling for heat it will not cycle at all.
 
That's interesting... Is it possible given the age of my boiler that it won't have the capability beyond on and off? It is 31 years old

Have you got both optimize options set I gather? I've set the start up option for 1 hour prior
 
Not yet.... That's on the new system which will be fitted at the start of next year. I've a few jobs to do yet... Including sorting the electrics, clearing space and shifting things for the new cylinder etc...

This is the original 1986 boiler and open vented cylinder. Not doing bad considering
 
Not yet.. That's on the new system which will be fitted at the start of next year. I've a few jobs to do yet... Including sorting the electrics, clearing space and shifting things for the new cylinder etc...

This is the original 1986 boiler and open vented cylinder. Not doing bad considering

Yeah that probably won't modulate, but you should be able to adjust the flow temperature manually.
 
I apologise for being late responding on the thread. However Drayton have released a good system this week. Just mentioning it as it gives other people reading the thread another option to look at. Should they wish.
 
Slightly old thread resurrection!

I wanted to come back to you all and say thank you for all the guidance on this project. It was finally completed in July - I am absolutely blown away with the results. Definitely worth all the hassle - huge shout out to my heating engineer who took the Atag course especially for my requirements due to the Viessman not working properly with Opentherm.

PureGas Services on Instagram: “First @atagheating boiler fitted as requested by customer #hvac #copper #plumber #gasengineer #puregas”
 
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Thanks for coming back

Everything looks great except my opinion few snagging points

D1 is too long
D2 is too shot
(Unvented safety vent d1 is the distance to the tundish 600 mm max, d2 is from the tundish to the first bend 300mm min)

Condense doesn't look likes it's falling might be the pics

Are the pipes now insulated?
 
Thanks Shaun!

There is a very slight drop on the condense... The other areas, D1 and D2, are you saying the tundish should have been mounted further up?

Is this the end of the world type deal where i need to get him back?

I might have impacted this as needed this area to be compact, as a fridge lives next to this area, pushed up (but not touching).

Thanks

Tim
 

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