central Heating Roomstat

[patmore]

I have recently installed central heating with Honeywell Timer - choice of continious, twice a day or once a day settings for heating and separately for water. I also have thermostatic valves on all radiators.

The problem is that I have no roomstats and the valves on rads go off lower than setting 3 or fully hot on setting 4. I am using honeywell timer, a grundfos pump, and an aluminiun valve on a T section coming away from the emersion tank.

I want to know what sort and how to install a room stat - how to wire it up etc.

[alegeegee]

Get a central heating engineer to balance your system properly. and then explain the interactivity of an averaging stat and TRV's

[patmore]

Thankyou for this advice but a heating engineer installed all this for me two years ago and it has always been the same. I dont understand what you are telling me about in your last sentence.

[stanleyman]

I don't see what your problem is with the TRV's. You simply set them by trial and error to the temperature needed in each room. If they go off lower than three then this means the room is already up to that temperature. Make sure the heads are fully screwed down and locked onto the valves otherwise they won't work properly.

Some systems do work better on a roomstat and for ease of installation you could fit a radio controlled roomstat or programable stat. The Sunvic from B&Q is good value at �55. Only three wires are needed from the existing Honeywell or terminal box to the sender unit, a live from the Honeywell heating on terminal, a switchline connect to the wire you have just disconnected from the heating on terminal and a neutral. The Honeywell will need to be set on 24 hours heating to give full control to the Sunvic if it is a programable stat and not just a stat.

[patmore]

Hi Stanleyman,

Are TRV's the Valves on the radiators? - I take it they are. Although female I can do many of the jobs myself - ie rewired my place in the past, build walls, plaster, plumbing etc - Dont always know the exact name for things though.

I meant that there is no graduation - The minutest turning above or below 3 is off or full on. If I go 3 and a gnats whisker they are full on or the most gentle caress below 3 is stone cold off. Its a big 4 bedroomed house with lots of double panel radiators.

So are you saying that I take my sender unit and connect a live to the live terminal in the honeywell heating on terminal, take the live from the Honeywell heating on terminal, then add a switchline to it to the sender, and a neutral from the neutral in the honeywell terminal to t the sender?

[stanleyman]

The thermostatic radiator valves (TRV) are fully open giving full heat to the radiator until the sensor detects the room temperature has reached the required setting. It then closes fully until the room temperature drops sufficiently to open the valve again.

The numbers equate to temperature i.e three is usually 21C but the position of each one varies the operating temperature. They are designed to maintain a set temperature, plus or minus a few degrees not to give a variable output as you seem to be suggesting. A roomstat will work in the same way.

Your last paragraph is correct but if using a programable stat the live can come from the live terminal to bypass the Honeywell heating control.