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So, the background. (and thanks in advance for reading...)
I have a gas combi boiler (no hot water tank - eg on demand) it works fine but it's probably a little underpowered since the attic conversion (though it kept the house warm fine last winter when it was pretty cold).
I've had a few problems with TRVs sticking over the last few years - usually fixed by removing the dial and just moving the value manually to unstick it. It does seem to be happening increasingly often though
One of the radiators (an old fashioned cast iron type like [url= 
]this[/url] but with a TRV) is now completely cold despite the other radiators all working fine. In the past this has happened and bleeding the radiator slightly has sorted it though there was never any air released so I wondered if there was a slight blockage and bleeding it was enough to shift it. Now bleeding produces plenty of water (still no air) so there's pressure but no heat.
There's also one other radiator in the bathroom where the central heating branches off to the attic that doesn't heat despite there being pressure when bleeding (eg the same as the cast iron rad) but since there's also a towel rail which gets plenty hot, I'm not too worried about that one.
The system as a whole:
Downstairs:
- Boiler
- Three rads in the main living area/kitchen all with TRVs
- Rad in the hall with TRV
- Rad in the front room with TRV
1st floor
- three bedrooms with 1 rad in each (inc the cast iron one) all with TRVs
- Bathroom with 1 rad (with TRV), 1 heated towel rail (no TRV)
Attic
- Bedroom with small rad (no TRV)
- Shower room with small towel rail (no TRV)
Ideally I'd like to sort it myself (I can drain the system and replace the sticking TRVs myself) but since I've been considering it anyway, I'm quite tempted to get a Honeywell wireless system at the same time.
What I'm thinking is this:
A more controlled system would manage heat across the house better because you're not overheating some areas (which always happens to some extent with TRVs IME) while underheating others (due to capacity)
So I'd replace my current controller with:
[url= http://www.honeywelluk.com/Products/Systems/Wireless/CM727/ ]Honeywell CM927[/url] kit, putting the thermostat in the main living area (and what's the difference between the CM927 and [url= http://www.honeywelluk.com/Products/Systems/Wireless/evohome/ ]Evohome[/url] - just newer/ more posh looking?)
[url= http://www.honeywelluk.com/Products/Systems/Wireless/evohome-zoning-pack/ ]HR80UK valves[/url] on the radiators in the four bedrooms (replace non TRV in attic bedroom with one of the HR80s)
Other rads to retain either current TRVs or no-TRVs
In my mind, that would mean
-The living area would be kept constant by the main thermostat
-The bedrooms would be controlled independently of the main living area (eg so the heating could come on to warm them up even if the living area was fine)
- Other rooms/bathrooms would be heated when there was heating running for either the bedrooms or living areas - eg they'd be warmed by default when other rooms demand it.
Or have I completely misunderstood how it'd work?
Thanks for sticking with it 🙂
I struggle with long sentences, but I'd start with flushing the system
EDIT: We've got the 927, and I don't think it does zones, the evo look like it does.
The 927 is a good bit of kit, and I'm pleased with it.
I have however have a mate who has installed these - http://www.heatmiser.co.uk/web/index.php/wifi-thermostats/multi-link-multi-zone-interface-module
which would give you zones and funky iphone / android app to play with.
Ta 😉
Yeah, flushing was where I was going to start.
We have a honeywell programmable stat, its fantastic, but I wouldn't get one until you sort out the problems you already have.
Even though you have pressure when bleeding, this could be entering from the return side through the lockshield valve, and not through the potentially stuck thermostatic valve.
It also could be a balancing issue. Go around the house and close all the thermostatic valves. Then close the lockshield valve on the cold rad, counting the turns and making a note. Then fully open both valves and see if it warms up, if it does then it wasn't receiving its fair share of water and you need to rebalance all the radiators (or get a plumber in). (or the increase flow caused by shutting off all other routes for the water has cleared a blockage or airlock in the pipes) It could be caused by kids/visitors opening just one lockshield valve somewhere and messing it all up.
Balancing: As a general rule, rads near the boiler will have the lockshield almost closed, and rads futhest away (attic) should have the valves fully open. This restricts the rads closest to the boiler from providing an easy return loop, which means the hot water would never get upstairs.
Even though you have pressure when bleeding, this could be entering from the return side through the lockshield valve, and not through the potentially stuck thermostatic valve.
That's what I figure though you're right that rebalancing would be worth checking first, particularly as I'm not certain it was done when the conversion was done not to mention that since there are no TRVs on the rads in the attic, one could have been adjusted accidentally...
Regardless, however it gets sorted, I do still want to look at the Honeywell system.
geoff
are those heatmisers anygood ? i read some reviews that said gimicky and over complex for their intended purpose ?
Some real world experiance would be handy as i want something to control my hot water output on my combi also.
As for wiring, top is the Honeywell controller, bottom is the existing one (Lifestyle LP111). To me that looks like they're different with the three RH connections (A,B,C) being one to the right on the honeywell compared to the old one - eg old to new
N->N
L->L
L->?
1->A
2->B
3->C
So what does the second L on the honeywell correspond to on the old one?
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Terry - my mate's been using them for about 6 months, without any problems. Hardly a long term test, but they seem pretty good to me. I did the port forwarding and DNS stuff. The iPhone app is very nice, and the customer support was excellent - I needed to call to find out which ports to sort.
Only time will tell if they are reliable, but they seem pretty good to me.
I've a couple of those wireless stats with the associated valves if you're interested. We had them operating for about 2.5 years without problems provided the batteries didn't run out but they're now redundant with a new system fitted. Can't remember the model number off hand but can let you know later?
Paul