If I were to fit an upstairs radiator I guess I would drain the radiators by the air bleed on one of the down stairs radiators? (though maybe quite slow and messy)
If I were to replace a downstairs radiator I guess I would just undo the tap to the radiator and catch the water as best as possible?
Is there any better way to do this? If I am fitting radiators 1 or 2 at a time to replace the whole house woudl it be a good idea to fit a drain tap (that could be connected to a garden hose to drain outside) somehow?
You can't drain a rad from the bleed screw, the bleed screws are at the top for abvious reasons. You can get pipe freezer kits if you are only changing one rad. Draining the system is not hard, I had to do it one evening about 10.30pm when one of my rad valves snapped.
No, you need to have and use a drain valve fitted downstairs. If there isn't one, then you will have to drain at a downstairs radiator by opening a valve union carefully over something to catch the water.
Heating water is able to indellibly stain carpet and other items.
The best solution would be to replace all the radiators in one go. The problem with draining and refilling is that you are using fresh water each time. Inhibitor should be added to prevent corrosion when a system is refilled. If you run off the water to waste each time, it means a new dose of inhibitor.
One strategy, if you were going to replace all radiators in say a period of a month would be not to bother with inhibitor and refill each time without until the end. However, draining and refilling is time consuming. Undr these circumstances you wouldn't have much corrosion problem.
Another would be to use a cheap inhibitor each time (can be bought for around £5-8) and dump it each time. That would allow you to do the work over a longer period. Then at the end you could use a proper inhibitor such as Fernox or Sentinel.
A third approach would be to have a means to store the heating water and then to put the same back. I use this method for my workshop secondary circuit. This runs part way outside and underground and even though well insulated, in the case of equipment failure there is a risk of freezing. So the circuit is filled with a solution of Fernox Alphi-11 which also contains an antifreeze. In case of a need to drain, I can do so into storage vessels and then pump it back in again after maintenance using a pressure sprayer plus adaptor for the purpose.
Another general tip if you are replacing radiators is to buy good quality valves such as Invensys TRV4s for the TRVs and Pegler Terriers for the lockshield valves. There is a version of these that has a drain on the valve tail on the radiator side. Thus you can close the valves and open the drain at one radiator (e.g. for decorating) without draining the entire system.
Overall, the best idea is to do all the radiators in one go if you can.
I quite frequently have to remove single radiators to decorate behind them. Here's how I do it:
- Turn off both radiator valves (one is usually a lockshield valve where you have to remove the plastic cap and use a spanner or screwdriver to close the valve - make a note of how many turns you needed to close it, you will need to open it the same amount when you have refilled the rad in order to retain the balancing of the system).
- Choose the rad valve at the opposite end to bleed screw (that's usually the lowest end of the rad) and either use a piece of kitchen foil to fashion a funnel that goes up behind the valve and rad tail and leads the water down into a bowl or tray or do something similar with a plastic bag and string, and tie the bag around the pipe either side of the nut, leaving an opening to use a spanner on the nut that fixes the valve to the rad tail.
- Unscrew the nut a little at a time and adjust the foil or bag so that any water runs into the bowl. If you have a cup and second bowl you can bale out the first bowl to avoid having to stop the flow of water while emptying a single bowl.
- After a minute or so you will have to undo and remove the rad bleed screw to allow air in at the top of the rad.
- After all the water has drained off you can completely unscrew the nuts to the valves and remove the rad, but beware there will still be a little bit of very dirty water at the bottom of the rad. I usually tie a plastic bag over the ends of the rad tails to prevent messing up the carpet as I lift the rad off.
It's a bit slow and tedious, but if you are only removing one or two rads at a time it beats draining the whole system.
I'd be surprised if there was no drain somewhere in your system. They are quite small so you could miss it. Mine is half hidden behind the floor-mounted boiler.
If there really isn't one, then the advice to change more than one radiator is a good one. Each time you drain you waste the inhibitor. Of course for an upstairs rad you only need to drain down to just below it, not the whole system.
Non-one has mentioned freezers. If you find you need to replace just one rad, and the valves, then you can freeze the pipe stubs each side after removing the rad. This gives you about 20 minutes or so to whip the valves off and replace them. You can do the rad much more slowly. The advice to use a valve with a drain on a downstairs rad is good. That's my next job. My drain valve has sludged up.
You might find that the new rad is a bit narrower. You can get sliding fittings that allow you to fit one that is up to about 5cm narrower. I recently used one for the first time with some scepticism, but it has been fine. Mine is not a pressurised system. I don't think the sliders are suitable for them.
This raises a point that I had not considered before.
We used to have a floor mounted cast iron boiler until a few years ago and it had a drain point at near enough floor level. I have drained it several times, quite successfully.
Since then, we have had a new boiler fitted that has the system drain at about 5 foot from the floor and a radiator fitted in the utility room that used to house the old boiler. The rad does not have any way to drain it down, as it is tapped into a rad that is on the half landing of the stairs. Hence it is a dead leg. This rad has SOVs to enable me to drain this part of the heating down by removing/changing a rad valve, but...
How do I drain down the lower floor of the heating system? When the boiler drain is above all the lower floor rads.
I have considered adding a combined rad SOV and drain point to the lounge rad and venting it to a pipe outside of the house. The drain point will not be visible from the lounge as it is behind the chairs.
If I do this, will all the heating water get drawn out of the system?
As I said earlier, when draining from the old boiler, I never took into account that the lower floor pipes were fed from upstairs.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.