New Gas Boiler & Evohome

Inconspicuous

Hello all.


Sorry in advance for the long post, but I wanted to get your help and give as much info as possible. I’m looking to do an overhaul of our heating system and I’m hoping some of you might be able to share some advice, tips or experiences.


Basically, at the moment I have an old system (probably 20 years old) with a gas boiler, hot tank, single zone with a manual summer valve so that we can only heat the water and timed controller for the entire system. We've been told that the boiler is on its last legs and we'd be better off replacing it rather than trying to repair parts of it.



What I would like to end up with is a smart controlled system (intelligent and with smart phone control) with some automated zone controlling and possibly hot water on demand (not essential).


The breakdown is a follows:


House (2 Story Detached):


4 Bedrooms (1 x radiator in each)
Kitchen / Dining ( 2 x rads)
Sitting Room ( 2 x rads)
Sun Room (2 x rads)
TV Room (1 x Rad)
2 x En-suites (2 x Towel Rails)
Main Bathroom (1 x Towel rail)
1 x WC (1 x Towel Rail)
Hall (1x Rad)


Excluding the hall and landing, I’ve measured out the living space above to be ~ 125m2. In total there are 12 Radiators and 4 Towel Racks on the system.


The current boiler is a gas powered Potterton Suprima 80 located in our utility room. As above this is controlled using a simple digital timer. We also have a manual valve above the boiler that we can close in the summer so that the boiler only heats the water in the hot water tank. The current hot water tank is a simple copper tank with no insulation. We have tried our best with lagging jackets and blankets etc. to insulate it.


Boiler:


I have been considering two options.


Option 1:
The first is to simply replace the current boiler with a newer and more efficient boiler while replacing the current hot tank with a modern insulated version. Do you have any particular recommendations around which brands are good and which I should be avoiding?


Option 2:
The second option I’ve been considering is replacing the boiler and current tank with a combi-boiler. I have a number of reservations about this especially since I’ve heard these types of boilers can prove problematic. However, my brother in law who lives in an identical house in our estate has recently renovated his entire house and was able to install a Glow Worm Energy 35 Store boiler in his garage to supply his whole house. He and his wive rave about the instant hot water and highly recommend it.


This is why I’m considering it. However, this boiler is too large for our utility room and our garage is located further back from our house and would likely require about 4 – 5m of Calpex to be run underground from out utility room wall back into the garage. Not to mention a water supply as well. This is not cheap and to be honest is putting me off this setup.


However, I have found a boiler called a Viessmann Vitodens 111-W 26kW Storage Combi Boiler which would appear to have smaller dimensions than the glow worm and would likely fit in our utility room. This would appear to do the same job. It is bloody expensive though!


A few questions I have around combi boilers:
Are they fed off the mains?
If so what sort of pressure do they need (I don’t think our pressure is particularly good)?
Can they be fed from the tank in the attic? (We have a sink in the utility room, but from the pressure in the cold tap it would appear that it is not mains fed.)


Heating Controls:


I’ve been looking around and I’m drawn towards the Evohome system from Honeywell. It’s not cheap but seems to do the job. All of the rads in my house currently have TRVs so it would appear to be a simple job to replace them with the ones from Evohome. I’m trying to keep the budget down so initially I was thinking of just buying the main controller and 8 TRVs to do the 4 bedrooms and main sitting room and kitchen/dining areas. If I keep the water tank then I plan to add a motorised valve to the water tank circuit so that this can be controlled by the Evohome controller as well. Presumably I will also have to replace the manual summer valve with a motorised one so that the system can only heat the hot tank during the summer.


This setup wouldn’t be as efficient as having all of my rads fitted with Evohome TRVs but it would hopefully give me some sort of zoning capability and temperature control. The idea would then be to fit further TRVs when I get more money together. What do people think of this set up? Is it doable? Would it work? Are there other systems (better, cheaper, etc?) that I should be looking at?


Finally:


I intend to have the entire system power-flushed when installing the new boiler. Is power-flushed the right term? Basically I want to clean out the whole system and try getting it back to optimal performance. Is there anything else I should be considering while I have the system drained? I’ve heard about having draining valves fitted at each radiator but don’t know about these or whether its worth adding them. I’d love to hear some views on them or on anything else I should consider adding to the system.


Lastly, is it possible to fit TRV valves to towel rails for future integration into the Evohome circuit?


Again, sorry for the long post, but I appreciate any help you can give.


Thanks

xl500

I can only talk about Evohome as I use it myself

If you are going Evohome Route I would definitely recommend the HR92 TRVs for Living Areas but I would buy just one extra and try it in the master bedroom first to see if you can live with it they can be a bit noisy for bedrooms and if heat is coming on an hour before you get up could cause you to wake an hour early

Yes you can put a normal TRV on Towel Rad etc and later just Put a HR92 Head on it and integrate it into Evohome


If you are going to use Honeywell Evohome I would advise you use these TRVs

https://www.amazon.co.uk/Honeywell-Valencia-VTL120-15-Traditional-Lockshield/dp/B00NIXGJ10/ref=sr_1_1?ie=UTF8&qid=1540018853&sr=8-1&keywords=honeywell+valencia+vtl120-15+a

Of course you replace the Head with a HR92 Valve and only use the Body but its almost the same price to buy them with heads anyway and they will do you in all the Rooms where you want to use Basic TRVs until you upgrade them You can use others but these are Honeywells own and work very well with Evohome other cheaper ones you can have problems with non-Linear Stroke or poor Temp Regulation etc

boosabum

In the process of installing an EVOhome kit myself and need to get TRV's to suit.
Looked at cheaper one's but are you advising to go with the honeywell ones as they work best ?

xl500

boosabum wrote: »

In the process of installing an EVOhome kit myself and need to get TRV's to suit.
Looked at cheaper one's but are you advising to go with the honeywell ones as they work best ?

Well if you are going to the Expense of installing Evohome which is not a cheap system it makes sense to use the Honeywell Valves as Linked the difference is not much and those Valves work very well with the HR92 Actuators ie proper stroke and temp regulation etc

Check out

https://www.automatedhome.co.uk/vbulletin/forumdisplay.php?13-Heating-Control&

Lots of Evohome users on there and you will see some other TRVs are not great

XL500

Inconspicuous

Thanks for the advice. It's food for thought.