hi, moved into new house a month ago and the rads on the top floor (three storey house) have never been exactly hot. today there is no heat coming from them whatsoever but rads around rest of house are fine. tried bleeding them to see if there is an airlock but just water comes from them. On the boiler there is a Zilmet tank valve that says something about it needs precharging once a year...could this be the problem??? if so how do i precharge it
cold rads on top floor
- Thread starter tonyth
- Start date
have a read through here
If some of your rads are not getting their share of hot water you need to balance the system. This involves opening and closing rad valves to divert hot water so that all rads heat up more evenly.
Click HERE for details.
The Lockshield valve above is adjusted to control the flow to each rad.[/quote]
Possibly but I wouldn't have thought just one rad would make a difference.
Try turning off all of the other rads and see if the heating starts to come through on the top floor. Then work your way down until you get heat at all of the rads.
If this doesn't work the pump might be failing or maybe undersized, if it has a speed setting try adjusting that if the above doesn't work
Good luck hope you get it going 
When the system is running normally feel the pipes either side of this valve, one side should be a lot cooler than the other, if both sides are the same temp it means the valve is opening and your loosing pressure to the top floor.
no wonder the top rads aint heating up 
turn it to number 4 and see if the rads heat up, this valve also acts as a boiler bypass so you will have to make sure the boiler isint over heating when the zone valves shut.
turn it to number 4 and see if the rads heat up, this valve also acts as a boiler bypass so you will have to make sure the boiler isint over heating when the zone valves shut.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
