Summer is here and this is a good time to be working on your heating system.
Have a look at all the valves that you think need changing, e.g. they do not work or show signs of leaking esp round the spindle. If they are all old it would be a good idea to renew them all. I also recommend putting lockshields with drain-offs on the downstairs rads, especially any near an external door that you can put a hose through, and they are essential on any rads fed with pipes that come down from the ceiling.
You may find your old drain cocks are choked or perished and need new washers, so this is a good time to fix them.
TRVs are much more expensive than ordinary valves (which are very cheap). Drayton make a TRV4. Danfoss a Ras-C². they are both good ones. there are cheap ones at the DIY sheds for half that which may not last...
If you buy a Radiator Wrench/Spanner/Key for a few pounds (it is an L shaped hexagonal tool) you will probably find you can unscrew the plug in the broken bleed screw in it, and fit a new plug and screw. If you look at replacement bleed plugs in the DIY or plumbing shop you will see how they work. You can use the same key to unscrew the throat of the old rad valve (warning: the rad must be firmly fixed to the wall while you do this).
If you can run the pump for a few weeks with a desludging chemical like Sentinel X400 it will loosen a lot of old sludge so that it comes out when you drain. I don't suppose you want to run the heating at this time of year so maybe do that when the colder weather comes.
If you can drain down the system and take the rads into the garden, you can squirt out the sediment with a garden hose, this is quite effective.
Bale out any mud from the Feed & Expansion tank in the loft (if you have one)
When refilling, it is essential to use a corrosion inhibitor such as X100.
the chemical will cost you about £15 each.
If you can do basic plumbing and afford an extra £100, a Magnaclean will delight you by trapping a lot of circulating black sediment.
p.s if any of your rads show signs of rust, replace them.
If any of the rads seem undersized (i.e. room slow to warm up) it will not hurt to replace doubles with singles. If they have TRVs then the room will not get over-hot.
Manual drain and flush, with X400, and preferably a Magnaclean, will get a lot of dirt out, and may avoid the need for a costly powerflush. As it is so cheap to DIY it is always worth trying, it will certainly do no harm and will probably do a lot of good.
i am just a householder.
