Hot pipes, Cold Rads

[GLarkin]

HI All,

Got a three story house, 1 year old baxi gas system. Heating was perfect until I left the heat off for the summer and am now having problems.

The Rads on the middle floor( where the hot tank is) are boiling.
The rads on the ground floor are freezing ( where the gas system is) and the rads on top floor are freezing.

The pressure guage is at 2, I have realised extra pressure into the system and it helps the odd time but the problems still exist.

The main problem is that the pipes leading into the rads are piping hot and never seem to enter the rad part ( all valves are open) leading to the the rad being cold.
On the off chance that they do heat up, the return pipe is always still cold,

Any help would be grateful

 

[Softus]

Sounds like you have some sticking rad valves. What type are they?

 

[GLarkin]

It's just a standard lockshield wheel valve if that makes any sense?
The radiator heat levels on the ground floor seem to change every time I put on the heating, sometimes warm and sometimes cold.
Thanks

 

[Softus]

OK - the action you need to take is commonplace...

1. Turn off all rad valves (i.e. at both ends) except for one rad.
2. Run the system until that rad is hot all over.
3. Turn off the rad and turn on a different one.
4. Repeat for all rads.
5. Open all valves, turn off the heating system, drain the system.
6. Repeat steps 2, 3 and 4 with the drain cock still open.
7. Turn off the water, fully empty the system and close the drain cock.
9. Re-fill, vent, and then turn on the heating.

If this makes a substantial difference then drain once more and re-fill, this time adding a chemical inhibitor.

 

[JohnD]

OK - the action you need to take is commonplace...

1. Turn off all rad valves (i.e. at both ends) except for one rad.
2. Run the system until that rad is hot all over.
3. Turn off the rad and turn on a different one.
4. Repeat for all rads.
5. Open all valves, turn off the heating system, drain the system.
6. Repeat steps 2, 3 and 4 with the drain cock still open.
7. Turn off the water, fully empty the system and close the drain cock.
9. Re-fill, vent, and then turn on the heating.

If this makes a substantial difference then drain once more and re-fill, this time adding a chemical inhibitor.

Hello, Softus, is that right? step 2 - run the system to hot, but repeat with the drain tap open? Surely the boiler could be dry?

 

[Softus]

OK - the action you need to take is commonplace...

1. Turn off all rad valves (i.e. at both ends) except for one rad.
2. Run the system until that rad is hot all over.
3. Turn off the rad and turn on a different one.
4. Repeat for all rads.
5. Open all valves, turn off the heating system, drain the system.
6. Repeat steps 2, 3 and 4 with the drain cock still open.
7. Turn off the water, fully empty the system and close the drain cock.
9. Re-fill, vent, and then turn on the heating.

If this makes a substantial difference then drain once more and re-fill, this time adding a chemical inhibitor.

Hello, Softus, is that right? step 2 - run the system to hot, but repeat with the drain tap open? Surely the boiler could be dry?

Quite right, although step 5 should indicate my intention. The corrected sequence is:

1. Turn off all rad valves (i.e. at both ends) except for one rad.
2. Run the system until that rad is hot all over.
3. Turn off the rad and turn on a different one.
4. Repeat for all rads.
5. Open all valves, turn off the heating system, drain the system.
6. Repeat step 1, then repeat steps 3 and 4 with the drain cock still open.
7. Turn off the water, fully empty the system and close the drain cock.
8. Have a cup of tea.
9. Re-fill, vent, and then turn on the heating.

 

[JohnD]

! and repeat step 8 unil job is finished!

 

[GLarkin]

Cheers Lads,
But one quick question, I know i have a drain cock on the middle floor on a pipe near the hot water tank but i don't seem to have anyway to drain the system/ rads on the ground floor ?

 

[Softus]

The drain cock near the cylinder - what is this connected to? Usually it will be the cold feed to the DHW for the cylinder, and no use in draining the CH circuit.

If you can't find a drain cock for the CH then you should call the installer back and kick him around the garden until he promises to fit one FOC.

However, you might find one near or within the boiler enclosure.

 

[JohnD]

I too have a 3-storey house, wuth a concrete floor, so the ground floor rads are fed by pipes that drop down though the ceiling. i found two drain cocks in the garage where two of the drops are, they go through the wall into the living space to look neat.

Howevever, one of the rooms did not have a drain. I later fitted a lockshield valve incorporating a drain-off valve on each of the ground floor rads to make future draining easier and more compete, at the same time as i fitted TRVs. Very cheap from Screwfix and an easy job for a summer afternoon. http://www.screwfix.com/app/sfd/cat/pro.jsp?id=11074&ts=80666

 

[GLarkin]

Thanks a million lads