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DW89 · Joined: 06 Oct 2003 Posts: 49 Location: Nottinghamshire

Guys n Gals,

Having a new system put into my 3-Bed detached which will utilise a Worcester-Bosch 14-19 CBi Trad Boiler on a Y-Plan system with new Cylinder, Thermostate and Immersion etc etc. This will service 3 Bed Rads, 1 Bathroom Towel Rad, 2 Living Room Rads, 1 Dining Room Rad and 1 Kitchen Rad. i.e. 8 Rads

Where is the best place to have the Room Thermostat for best effect? Which Rads should then have the TRV's on? I don't want to have one in the bathroom but apart from that I am open to suggestion. The coldest room in the house always seems to be the lounge even though there's two rads....though I am guessing TRV's, new improved system and Room Thermostat will improve all this??

Also what, if any, is the difference between a 'lockshield' valve and a normal valve? I have new valves that I want to put onto the other sides of the rad from the TRV's but don't know whether them being 'lockshield' or not comes into it.

Finally, on a basic level...if I drain the system entirely to re-fill is there any difference on doing this with TRV's to when I used to do it without TRV's? i.e. Open rad vents, drain, re-fill and purge air? I was told I will need an Auto Bypass by one plumber and then another said only if ALL rads have a TRV....confused!!

Thanks very much. Just trying to understand so that I can talk to the plumber!

jonesey · Joined: 15 Jul 2003 Posts: 13 Location: croydon

You can have a bypass on a radiator if you have a lockshield on both sides of it. The theory of a lockshield is that someone cant turn the head and turn the valve off. On a system with radiators all having trvs there must be a bypass, if all the trvs were to reach temperature and turn off, the flow of water would have nowhere to go. Some boilers have a bypass in them, or a bypass can be cut into the system.