Refitted radiator problem

kiwijbob

I removed a radiator as the bracket behind had loosened, the bracket
has been replaced and I've refitted the old radiator now. I attached
the supply pipes to the rad and opened the bleed valve and then
opened the supply and return valves to let the hot water in.....now
the boiler (ideal classic ff340) is making a noise like wind howling
outside in a storm? there isn't must air coming out of the bleed
valve and the rad in the bedroom isn't heating at all now (it's cold
tonight!!:(), there doesn't seem to be much air pressure coming out
of any of the bleed valves in the rads like there's very low pressure

any ideas...cheers

Pete67

It sounds like the system is low on water. If its a sealed system you'll have to add water to make up for the lost water when you drained the radiator. There should be a filling loop (flexible connection to the mains) to top up the system. Top up to a pressure of approx 1 bar when the system is cold. Then go around and vent all the radiators until no air remains in the system. You may have to top up the pressure several times during the venting process.

If it's an open vented system then the ballcock in the feed and expansion tank may be stuck. Normally the F&E tank keeps the system full automatically so you can vent air without needing to manually add water.

It's a good idea when refilling a radiator to only open one of the rad valves until all the air is removed from the radiator via the vent. Otherwise you run the risk of pumping air around the system and into piping and other radiators.

kiwijbob

Pete67 wrote: »

Otherwise you run the risk of pumping air around the system and into piping and other radiators.

cheers for the reply, this sounds exactly what I did, how did homer put it??? DOH:eek:

where would I locate the filling loop, I don't think I've seen it before??

Wavey

Hi Lads,

kiwijbob do you mind if jump on the back of this thread?
I have a similar problem.

I have just drained down my central heating system. I was told by a plumber that it was an open vented system.
But when I drained down the system, the tank in the attic did not empty. ( I had the ball cock tied up).
Also I only have one tank in the attic.

Does this mean I have a closed pumped system?
I know that my oil boiler does have a pump on the feed line to the house.

If this is the case, how do i refill it?

Would it be the same was as you have already suggested Pete?

Thanks,

Wavey.

Pete67

Open vented systems have a separate tank in the attic, usually smaller than the cold water storage tank. Mains water is supplied via a ballcock to top up the tank automatically.

Sealed systems do not need a feed and expansion tank, as the increased water volume on heating is absorbed by a sealed expansion vessel, which has a rubber diaphragm and an air cushion built in. The expansion vessel may be built into the boiler, common with gas system boilers, or may be installed separately. It's usually a small red cylinder about 12" dia and 12" high.

The sealed system can be filled in two ways - first option is a connection to the water mains via a double check valve and hand valve to fill/pressurise the system. This can be achieved with a filling loop (flexible pipe joining mains water to heating system - removable to prevent risk of the mains being contaminated by dirty water from the heating system) or a hard piped permanent connection using a pressure reducing set, double check valves and isolating valve.

The second option is fairly common in Ireland, and takes a feed from the main cold water storage tank via a check valve to the heating system. There may be a hand valve to isolate the heating system for draining down. If this valve is closed the system will not refill.

If you examine the pipe layout and sketch it out on paper it is usually fairly easy to determine which type of system you have. Hint - most of the pipes pass through the hot press.

I hope this helps, but if in doubt, seek professional advice.