Central Heating Cleaning

[BrinFranks]

I have drained my CH system down and although the drain cock finished discharging there were 3 rads that still spouted water from the air vents. I have now drained these as well. During the winter they heated up ok so I would be surprised if they were blocked. But advice would be appreciated. One of the rads had a drain cock beneath but did not discharge any water.

Also I will be replacing many lockshield valves, should I do this before I add the cleaning fluid and drain or after I have completed the final drain down.

All advice appreciated

 

[mountainman]

Replace any valves and then flush.

Use the appropriate chemicals in your powerflushing machine and clean the magnacleanse regularly.

 

[Richie_77]

Do the rads that don't drain on dropped piped work from above?
And the drain valve washers sound like there stuck.
change the the valves after you've cleaned out the system.
If your just using a chemical cleaner it's not going to do a great deal to a fouled system.

 

[Deleted member 32524]

If you want to do a flush you have a few options.
1. Put in cleanser, leave for 2-14 days. Heat up and drain, fill, heat up, drain and so on until you are happy you have removed all aggressive chemicals. Add system inhibitor.
2. Mains flush as it sounds flush central heating pipes with mains water. Remember the 2-14 days cleanser.
3. Remove rads and flush manually with mains water.
4. Powerflush.
Could get some PH paper to get a more accurate idea of how healthy CH water is at the end.

Always using cleanser and inhibitor.

 

[BrinFranks]

Appreciate all replies

 

[BrinFranks]

A further question.

I can see that the rads not draining are fed from above, which happens on a couple of runs. There are 3 drain off valves at the low points but only 1 works properly. I can see water in the pipe (having removed the LSV) but it will not exit via the DoV which is just below it. This is on two runs and I had to leak the water out of the rads. I have removed the drain screw and still no water came out. Is there a way to
1. Clear this blockage
2. Replace it (Soldered joints) simply.

I could put a lochshield DOV on one end of the rad but that still would not allow the water to be drained from 1st floor.

Appreciate any comments

 

[Richie_77]

The pipework isn't blocked the washer inside the drain off is stuck in there unwind the drain off until it drops out then get a small screw driver and pick out the remaining bits of washer. Go to a merchants and ask for some drain off washers look like little tap washer. Hope this helps

 

[BrinFranks]

The pipework isn't blocked the washer inside the drain off is stuck in there unwind the drain off until it drops out then get a small screw driver and pick out the remaining bits of washer. Go to a merchants and ask for some drain off washers look like little tap washer. Hope this helps

Thanks Richie for the tip seems a good idea as didn't think about a washer there, however when I push around with the small screwdriver inside the DoV I can only feel metal and still no water comes out. There is a small pin protruding which fits into a hole on the screw cap, does this move, can I twist it or pull it to release the pressure.

Going great guns with flusing out the rads, just keep getting stuck on draining the system.

 

[Richie_77]

Look into the hole where the washer would be see if there's anything blocking the it. With pressure in the system push a long thin screw driver into the hole and see what comes out just keep a hose on the DV and just stick your finger over the end until the water slows down or stops. Failing that cut out and replace the pipework but I wouldn't of though it would be blocked though.

 

[tamz]

when I push around with the small screwdriver inside the DoV I can only feel metal and still no water comes out. There is a small pin protruding which fits into a hole on the screw cap, does this move, can I twist it or pull it to release the pressure.

That is the valve stem. The washer is stuck (behind that) to the seating.
Pull it out with a pair of pliars (have a bowl ready)

 

[BrinFranks]

That is the valve stem. The washer is stuck (behind that) to the seating.
Pull it out with a pair of pliars (have a bowl ready)

Many thanks did that and it has worked perfectly.

Now got it under control.