Posted by: @kevh

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@jamespa Thanks for this...do you mean take the control knobs off the TRVs and replace with a decorators cap?  In addition to virtually locking down the LSVs?

Yes.

In addition or instead.  The point us that trv bodies with decorations caps offer an alternative (or additional) and more linear adjustment mechanism.

I haven't made any changes over the christmas period and waiting on Octopus to get back to work.  I do want to try the decorators' cap approach though as that can leave the LSVs where they are, as Octopus set them, whilst trimming down two vastly oversize radiators.  I think upstairs is mostly a lost cause as the landing is being heated by the rest of the house and always has been but the home office and kitchen area could do with a turn down.  Mostly, the house is now running at around 22.5c with some areas a little warmer, around 23c: landing, kitchen area which is open plan to the dining area and living area, office.  It does require 2 radiators to be upsized though.  These warmer temps are really a result of the heating being on a lot more with the Primary Pod in the downstairs WC (still running thermostatically.) I think the flow temp is more or less there, now it comes down to trimming the radiators for room temp and then maybe tweaking the flow temp some more.  Wife loves it of course, and I'm putting up with being a bit overly warm, so have to be careful not to mess with things too much!!

I always thought TRVs closed off a radiator once room temp was reached - is that not the case?  There's an implication here that it throttles the flow as temperature reaches the set point so acts as a flow restrictor as well.

Posted by: @andrewj

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I always thought TRVs closed off a radiator once room temp was reached - is that not the case?  There's an implication here that it throttles the flow as temperature reaches the set point so acts as a flow restrictor as well.

TRV heads do indeed close completely once room temp is reached (or thereabouts), by depressing the pin on the valve fully.  However there is a degree of progressive response in the valve itself so as the wax (or whatever the temperature responsive element is) expands and depresses the pin on the valve the valve itself partially closes.  Some electronic TRVs use this to their advantage and indeed Adia make what they call 'flow control valves' which use modified electronic TRV heads on a standard body to auto balance radiators by adjusting flow but never completely shutting off, specifically with heat pumps in mind (although the idea is just as valid for boiler).  Also if you look at some decorator caps (eg the ones originally supplied with Drayton TRV4s, at least when I bought mine) they actually have a +/- on them with arrows.

Makes sure you dont turn down all the radiators otherwise you are just unnecessarily restricting flow.  At least one (normally the one furthest from where the primaries start to split) should be fully open.  If the house is still too warm at this point the solution is to turn down the WC further (if necessary by fiddling with the OAT set points rather than the FT set points).

Posted by: @toodles

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@kevh The body of the valve remains - what you remove is the screw-on top that contains the thermostatic mechanism. All the TRV does is push the pin of the valve itself down in stages into the valve body as the temperature rises. When you remove the ‘top’, you leave the valve mechanism in place and can then use the decorator’s cap to push the pin down gradually - once you reach the degree of restriction required, you stop screwing the cap down any further. Regards, Toodles.

@kevh I found that Amazon sell a pack of ten screw on DC. Most of the other offerings appear to be push fit rather than threaded so beware! I tried to copy the link but this doesn’t seem to work so will try to capture the details via another route and post again. Regards, Toodles.

Posted by: @toodles

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TC Thermostatic Radiator Valve TRV Plastic Decorators Screw Cap for Radiator Valve White x 10

 

Sold by: TEAM-SUPPLIES

 

Maybe this will help. Toodles.

 

 

 

£12.95

@jamespa From what I have read, the Adia TRVs are installed to existing rads as part of a bespoke installation that includes a master hub which manages that whole system.  It sounds impressive, linking in automatically to TOU tariffs and WC.  

Alas for those of us with Octopus installations, and especially those with a Cosy ASHP, I can't see a way of retrofitting them without totally abandoning the Cosy hub.  

How the science moves quickly, eh.

Posted by: @kevh

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@jamespa From what I have read, the Adia TRVs are installed to existing rads as part of a bespoke installation that includes a master hub which manages that whole system.  It sounds impressive, linking in automatically to TOU tariffs and WC.  

Alas for those of us with Octopus installations, and especially those with a Cosy ASHP, I can't see a way of retrofitting them without totally abandoning the Cosy hub.  

How the science moves quickly, eh.

You are in essence right.  Adia only works with selected heat pumps and I dont think cosy is one of them.

Don't worry, none of this is necessary if you are prepared to balance rads and tweak the WC curve.

Just had my annual service by Octopus. The engineer replaced the pcb in side the Cosy6 without me prompting him.

I asked what the new PCB did, all he new is the firmware on the board is different and there is a change to the earth wire.

@jamespa There is no reason the Cosy couldn't auto-balance, they control the pump and the smarts. All you would need to do is have some software during commissioning. Grundfos already do this with the ALPHA2.

Posted by: @swwils

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@jamespa There is no reason the Cosy couldn't auto-balance, they control the pump and the smarts. All you would need to do is have some software during commissioning. Grundfos already do this with the ALPHA2.

I expect its something Octopus are looking at.  Given the scale of their operation any way to shorten the installation process and make it more robust is surely of interest.