Worcester 24cdi combi, trv's and roomstat

[LFC]

I have a worcester 24cdi combi boiler in a loft converted bungalow. My now retired plumber originally installed the system with no trv on the rad in the airing cupboard. Since completing my loft conversion and adding extra rads to the system myself i removed my old airing cupboard downstairs and made a new one with small rad upstairs. I left the trv off that rad as before but the door started to warp under the heat and wouldnt shut properly so i put a trv on that rad. So i now have a danfoss trv on every rad in the house. A friend who is a british gas engineer said this was ok because the boiler had an inbuilt bypass. is this correct because i've since heard different. I tried contacting worcester but all i got back was "To keep in line with current building regs (part L) a system should have an automatic bypass fitted, this can be achieved by leaving one rad, preferably the rad in the same room as a roomstat, open, (ie: no TRV). " So now i don't know who to believe. If i do need to leave a trv off can i not just leave say the lounge one on full? But also i have no roomstat so could and should i fit a wireless one such as the danfoss one in Screwfix? Also what is the gain of a roomstat over a trv? And why did the same british gas engineer tell me i may want to turn some of the trvs up in the winter on colder days? If say setting number three is a comfortable temperature, surely it will always be that temperature no matter how cold outside because it would adjust accordingly. With our system as it is now i do find its either too hot in the house or too cold. I can never seem to adjust the trvs to just right. If any of you could put me straight and provide some answers it would be much appreciated. Thanks

 

[pannierstan]

You definatly need a roomstat top control the system as a whole and then just remove the trv head on the radiator in the room where you fit the stat.
You will never get a system of TRvs to regulate properly without it.
You will also see your gas usage drop some aswell.

 

[LFC]

Thanks for the reply. So would that wireless Danfoss room stat in Screwfix (quickfind 70776) work with my boiler? I cant run cables now. Its all decorated. I couldnt face it. So does a roomstat actually stop the boiler firing and a trv doesnt?

 

[pannierstan]

1. I guess the Screwfix one will do if it actually works further than 5 feet. If its anything like the rads Ive seen

2.A trv will only stop the water flowing into that specific rad meaning the longer the heat is running the more rads will shut down meaning the boiler really is pointless actually being on.

A Roomstat although only controlling one specific area say a Hall will turn the whole lot off.
The secret is to get all the trvs set where each room is at the desired temperature you want

 

[LFC]

Thanks again. I've spoken to another friend who is corgi registered and hes gonna get me a price for the actual worcester wireless stat and receiver that will plug into the boiler facia in place of the mechanical clock. I will definitely get a stat of some sort, hopefully that one if its not too expensive. I just want it to be running at its most efficient. And from what youve said it will help me set a correct temperature and maybe save me a bit of money too. I will post back in a week or two with the outcome. I just wish the installer at the time had given me the option. He was a family friend and I think in all fairness he was trying to save me some money. And as i read in another post, if you give the customer a choice we tend to choose the cheapest and sh*ttest option.

 

[LFC]

Right. Got the worcester wireless stat today with the facia receiver. It is working great. Had to phone technical because I didn't join the ls and sr wires together. The woman sorted me straight out. I now have a nice comfortable constant temperature. Thanks pannierstan for taking the time out to explain it all to me. Once you did it all made sense. Thanks.