======================================== Yes, I did come across those amongst others when I was looking but the cost seems rather high (4X ) compared with other standard TRVs. I decided on something standard and possibly more versatile to experiment with.
Cic.
How, exactly, did you set about verifying that?
My view is that it sounds good in theory but that simply having correctly sized radiators without TRVs isn't going to get it right under all circumstances. There are too many extraneous factors - solar gain, cooking, other heat sources, doors being left open etc. - which can affect individual rooms and upset the best laid plans.
Jon Fairbairn wrote: > I find it rather sad that I can get something as complex and > precisely engineered as a hard drive for about £50, and yet > a wax filled piston with some resistance wire wrapped round > it costs £100.
It shouldn't cost that much. A quick google found a complete valve with electrically operated wax actuator for £22.99 here:
Rich.
I'm assuming you've got a room stat for the zone and/or weather compensation on the system to prevent that.
What I'm saying is that I find all the rooms seem to get the the right temperature at the same time, and I can just leave all the TRV's fully open. Now, if the radiators weren't all the right sizes and you don't have TRV's, some rooms would get up to temperature faster and overheat, or never get up to temperature, before the roomstat turned off the heating zone.
Not sure which of the suggestions you are commenting on. Oversized radiators are particularly good with condensing boilers. In this case, I deliberately oversized the radiators by 60% to allow for low flow and return temperatures for efficient condensing boiler operation (70/50).
Actually, I found they were oversized by much more than this in practise. I'm not sure if the Myson calculator I used got this wrong (it was a beta of a Java version which I don't think was ever fully released), or if I overestimated the heatloss of the various types of building fabric, but the system can maintain the house temperature with the radiators running at
45/40C with an outside temperature of -3C, which is actually much better than I had designed it to do.TRV's make up for mismatches in the ratios of radiator outputs and the heatloss between rooms. Increasing all the radiators by the same percentage won't change the relative balance between rooms, so it doesn't affect the requirement for TRVs; they'll simply all heat up faster (if the boiler has enough headroom).
I agree - more or less. In fairness to Andrew, I think he was assuming that a room stat would cycle the system on and off in milder weather - and probably that the capacity of each radiator included a bit of bunce for transient conditions. But the flaw in his argument is the assumption that the relative proportion of the total heat input required by each room will remain constant under all conditions - and that just ain't true.
I simply observed this in practice. Solar gain isn't an issue for this 1900 house. Other factors don't seem to be. The upstairs and downstairs are separate zones, and when you do the heat calculations, upstairs actually gets a significant amount of its heat from downstairs through the floors, rather than just from its own radiators. Perhaps if it was all one zone, the TRVs would play a more important part between upstairs and downstairs.
The big problem here is that the solar gain at the front of the house is enough to heat those rooms to full temperatures during the day even on frosty days. The rear rooms need almost full output. Without TRVs either one side is cold, or the other side too hot. Having TV, computers and occupants in rooms can completely screw up an otherwise balanced system.
Unfortunately SWMBO doesn't believe in either rom thermostats or TRVs. This is probably typical, so TRVs, whilst in theory are a Good Thing, aren't in the average home.
That's long been my feeling!
Excellent! Thanks for that. I suppose I might have found it had I done a proper search again, but having tried a few years ago and only found the Danfoss one, I wasn't optimistic.
On 12 Jan, 13:48, snipped-for-privacy@googlemail.com wrote:> I stumbled across this german product. =A0It looks like a programmable
seemingly very reasonable price - I can't believe no one has commented on the product.... does anyone have experience of the Sparmatic product? Mike
Your browser must be dling a different page to mine then.
NT
Try this instead...
NT
It looks like it would behave in a similar way to the Honeywell CM-Zone system except that there doesn't appear to be any reference to any form of relay box for the boiler. If that's the case then the boiler would continue to run and short cycle when all the TRVs were shut.
It does look like being cheaper than the Honeywell system though. A Honeywell installer pack with 1 x CM67Z Room Unit, 1 x HC60 Boiler Relay and 6 x HR80 Radiator Controllers would cost nearly 500 GBP. The picture of the SPAR matic implies that you get 2 TRV heads and a controller for 130 euros and then 50 euros for each extra TRV head which would come out at 330 euros for a 6 valve system, plus the cost of a compatible radio controlled boiler relay - if such a thing is available.
Look at this thread:
They are not required by Part L.
Hmm, not my experience. I don't like the bedroom at the same temperature as the living room, and the office needs to be cooler than the living room as well. But depending on time of day the heat loss from the office can be much greater than the bedroom, then in the afternoon when the sun moves the office can be in full sun.
Hence TRVs help to keep the rooms comfortable and the costs down.
I assumed one would not fit an electric TRV in the room with the room stat.
NT
[snip]
I suppose it depends how the system is configured. The shortage of information (and vague translation) on made it hard to know how the Sparmatic is intended to be used. I've now found the "official" English web pages . It appears that each TRV can be individually programmed - unlike Honeywell CM Zone where each TRV can be assigned to one of 2 zones.
The item which looks like it might be a wireless room stat appears to be an optional extra remote controller which can be used to programme or override the individual TRV's. I imagine this is the "SPAR matic control premium" which I wrongly assumed to refer to an extra head as the 49.95 euro item at the bottom of the page on .
The down-loadable user guide makes no reference to any remote control of the boiler so I assume that's not possible. If you combined these with an existing room stat controlled setup then there'd be no way for the Sparmatic TRV's to apply heat in one room if the main room stat elsewhere had turned the boiler off, this would significantly reduce the effectiveness of the devices.
In answer to an earlier query, according to the installation guide they fit most TRV's (Heimeier, Junkers, Landys+Gyr, MNG and Honeywell Braukmann) and also have adapters included for Danfoss RAV, RA and RAWL TRV's.
It's a bit over a year since I looked at (and eliminated) the Honeywell CM Zone system as a possible option when upgrading the controls on our heating system so the description that follows may not be entirely accurate. From what I remember, unlike Sparmatic, it provides full boiler interaction. The CM67z controls the programme for 2 zones, each TRV is configured to belong to one of the zones and it communicates directly to the HC60NG relay box which will activate the boiler if any TRV needs heat. With this type of system you would still need the wireless TRV for the radiator in the same room as the CM67z unless you selected the option to use the CM67z as a temperature sensor in which case it would act as the only sensor for zone 1 and would over-ride the temperature sensors in all the zone 1 TRV's.
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