Central heating radiators going cold downstairs when hot water put on.. Help!!

mikeluxy

Hi There

The Pump is set to Max (as was the old one) and yes the pump valves are fully open.

I dont think a "magnaclean" is fitted to the boiler (I assume this is a filter of some kind..?)...then again the Boiler was only replaced 2 years ago.

One thing I have noticed is that (when the hot water is on and we get cold rads downstairs) of the two pipes coming down from upstairs to the radiators one is hot and the other is stone cold.....this might indicate that the water is having trouble getting through the radiators....

Then again we had a full system flush 2 years ago.....do you think that the rads may just be getting too old and may need replacing....I think the rads have been in place for 15 to 20 years.

|Cheers

Mike

mikeluxy

In answer to the post by "closed" Yes all three pipes from the zone valve seem hot so I assume we can rule out the Zone valve...?

There seems to be no Bleed valve near the three way valve....

When the radiators are not heating up the 2 pipes down to each rad...one is hot and one (return?) is cold.

Do you think the radiators are knackered...?....but then again I cant understand why the downstairs rads get hot when the hot water is turned Off .....wierd!!

Finally No...the downstairs rads do not warm up when the hot water tank is up to temp.

Cheers

Mike

closed

any thermostatic radiator valves installed?

mikeluxy

Yes but not on all of them....2 in stting room have thermostats but not one on landing or one in downstairs loo......

closed

is downstairs loo hot, and what number are the other downstairs one's set to?

mikeluxy

Yes, the downstairs loo does get hot. THe others are set to 4.

closed

it sounds like the room is getting to temp (or trv's are faulty), so the valves are switching off as they should to save wasting energy, turn up to max or remove the head to see.

If not, a simple workaround is to set the timer to heat hot water at a different time, the lagged cyclinder should keep it hot

mikeluxy

Hi There

I have removed the heads of the TRV's and still no joy....and the problem is that the rooms downstairs are not getting to any temperature at all (just staying cold)..as mentioned the rads downstairs will only get hot if the hot water is turned off..im wondering if its a blockage in the rads and maybe with the hot water AND the rads turned on there is not enough "Oooomph" or power to push the hot water through the system.......?

closed

You could close the upstairs ones, to test the oomph, making sure the downstairs one's are all fully open. Strange that the only one that works downstairs is the one without a trv. But changing the timer seems the easiest solution, it also means the cold rooms don't cool down the hot water, 30 minutes a day on hot water should be enough for average use.

gas4you

Is there a balancing valve fitted to the return pipe that comes from the hot water cylinder back to the main pipe circuit? (May even be on the flow to the cylinder)

If so has this been opened recently? If you have one, close it fully, then open it counting how many turns it takes to open fully, then close it by just over half the number of turns and see what happens.

Do you have a bypass valve fitted between the pump and the 3 port valve? Although you don't need one with a 3 port valve, you may have one, so close this if you do have it.