Help Bleeding Radiators Please!

[Hitmo]

Hi all,

I know this is a simple task but I'm sure I'm doing something wrong! Let me start off by describing my system - I have a F&E heating system with a hot water tank in the airing cupboard, Gloworm 60FF boiler, 7 radiators (3 upstairs / 4 downstairs). And just to give you some background information - my heating system had poor circulation due to sludge build up (just bought the house, previous owners obviously didn't use any inhibitor) so I drained the system (to do some unrelated pipework), then took off every radiator and flushed it through with a hose.

I then refilled the system, and bled all radiators starting with the ones downstairs then moved up. After this I switched on the heating, and repeated the bleeding process as the radiators now had some pressure from the pump. Now here's where I'm struggling, I have some old radiators with the bleed valve pictured below, and I'm finding I'm having to almost pull them the entire way out and jiggling them about before I hear any air escape. After a few minutes of doing this the radiators start to get warm but they never seem to get hot like they used to (even though the flow pipe is boiling!) and I have literally tried bleeding them for 10 minutes with no luck. Am I doing something wrong? If I can still hear hissing, does that means there is still air in there? Also is my bleeding process correct?

Any help would be greatly appreciated

Cheers
Hitmo

 

[Dan Robinson]

Hissing could mean air is going in not out. . Is the system off when you're bleeding?

Could also have a blocked feed pipe.

 

[Newboy]

Pump may need bleeding?

 

[DP]

Pump may need bleeding?

That is bleeding obvious

 

[45yearsagasman]

Never bleed a system when it's running. As long as you get water from the rad, then the air bleeds are working ok. Ensure all rad valves are on. Bleed pump, and finally balance the system using the lock shields. If after all this you still have a problem, come back.

 

[Hitmo]

Never bleed a system when it's running. As long as you get water from the rad, then the air bleeds are working ok. Ensure all rad valves are on. Bleed pump, and finally balance the system using the lock shields. If after all this you still have a problem, come back.

Thanks for the advice, I will drain down and try again! Another problem I have is that when I refill the system, water doesn't get to the radiators by itself. I usually have to quickly turn the heating on for 2 seconds and then all of a sudden they all get water. Any idea what this could be? I've turned the 2 port valve to "M" but it makes no difference.

To clarify the bleed process I should;
1. Refill system with water
2. Fully open alll all trvs/lockshields
3. Bleed all radiators downstairs
4. Bleed all radiators upstairs
5. Bleed pump
6. Turn on heating system and balance system

Is that correct?

 

[Hugh Jaleak]

You've flushed the radiators, what about the pipework? Once you get it flowing I'd be tempted to chuck some Sentinel X400 in for a few weeks, then add inhibitor.

If the water isn't getting to the rads 'by itself' then there cannot be adequate pressure available to fill the system. Dan has already said you could have a blocked feed pipe, (quite common in a dirty system). I would check that and ensure it is clear! A magnet test is a good start, run a magnet along the pipe. If it attracts then there's your problem.

Motorised Valve needs to be in 'M' when filling the system, are you sure its a 2 port valve? If so there's usually another somewhere.

 

[Hitmo]

You've flushed the radiators, what about the pipework? Once you get it flowing I'd be tempted to chuck some Sentinel X400 in for a few weeks, then add inhibitor.

If the water isn't getting to the rads 'by itself' then there cannot be adequate pressure available to fill the system. Dan has already said you could have a blocked feed pipe, (quite common in a dirty system). I would check that and ensure it is clear! A magnet test is a good start, run a magnet along the pipe. If it attracts then there's your problem.

Motorised Valve needs to be in 'M' when filling the system, are you sure its a 2 port valve? If so there's usually another somewhere.

Hi Hugh, I was planning on putting some sludge cleaner through but I thought I'd hold off until I got the system working atleast as good as it was before I carried out this work!

I'm pretty sure its a two port, the unit I have is pictured below (pic from google), I have an an "M" and "H" on the side (not "W" and "H" as the pic shows). I'm 99% sure the reason the rads won't get water without quickly turning on the heating is something to do with this valve as the pump really doesn't do much in the 1/2 seconds I switch it on.

Sorry for my ignorance but which feed pipe are we talking about here? The one from the F&E tank?

 

[TeaTime]

That is a three port valve!

 

[Boilerman2]

It's like trying to talk Stevie Wonder though it!

 

[TeaTime]

To clarify the bleed process I should;
1. Refill system with water
2. Fully open alll all trvs/lockshields
Is that correct?

Please tell me that you have checked that the valves are open when you refill the system?

Well, assuming that your valves are all ok, you will need to add the cleaner via the F&E tank, as suggested.

Drain the system, shut off the inlet to the F&E tank, clean the tank out, shut the drain valve, pour in the cleaner, refill the system and away you go.

 

[Hugh Jaleak]

Can we have a picture of your valve then please and the associated pipework around it. Cold feed is the pipe (usually 15mm) that drops from the F&E (small) cistern and connects into the heating, usually near the cylinder.

System should fill via gravity, operation of valve and pump should not affect it, although it may fill quicker and reduce trapped air if the MV is open whilst filling. Valve wont do much in 1/2 a second, you need to give it chance! Once it gets power from the appropriate stat, the valve should then motor open, and once it reaches full extent of its travel, activate a micro switch. This in turn energises boiler and/or pump. However, it needs to be opened manually using control on the side for system filling purposes. It will reset once power is applied again.

 

[Hitmo]

That is a three port valve!

Ah... my mistake! I assumed because water was being distributed to 2 places it was a 2 port!

To clarify the bleed process I should;
1. Refill system with water
2. Fully open alll all trvs/lockshields
Is that correct?

Please tell me that you have checked that the valves are open when you refill the system?

Well, assuming that your valves are all ok, you will need to add the cleaner via the F&E tank, as suggested.

Drain the system, shut off the inlet to the F&E tank, clean the tank out, shut the drain valve, pour in the cleaner, refill the system and away you go.

Yes the valves are open, sorry I should have put "Make sure all valves are open"!

Can we have a picture of your valve then please and the associated pipework around it. Cold feed is the pipe (usually 15mm) that drops from the F&E (small) cistern and connects into the heating, usually near the cylinder.

System should fill via gravity, operation of valve and pump should not affect it, although it may fill quicker and reduce trapped air if the MV is open whilst filling. Valve wont do much in 1/2 a second, you need to give it chance! Once it gets power from the appropriate stat, the valve should then motor open, and once it reaches full extent of its travel, activate a micro switch. This in turn energises boiler and/or pump. However, it needs to be opened manually using control on the side for system filling purposes. It will reset once power is applied again.

I've attached some pictures below of my setup, the feed pipe to the tank is 22mm. Is putting the valve on "M" as pictured below all I have to do to allow the system to refill? I have no idea why but the water reaches the cylinder no problem when I refill the system, but its not untill I switch on the heating for 1/2 seconds that all of a sudden all the rads fill up.

3 port valve

Feed pipe on the left

Enters the cylinder at the bottom

Brand new pump

Thanks again for all your help fellas, I'm really quite new to this so I apologise for my incompetence!

 

[Hugh Jaleak]

Wrong feed pipe! Thats the cylinder feed from the cold storage tank, the CH water is completely separate.

The green can, it's a Myson 'aerjec', I would put a wager on that's full (blocked) with carp. (Try the magnet test!) The cold feed from the F&E cistern should join the system via the aerjec. The only solution would be to cut it out, it maybe possible to clean it, otherwise replace it. I'm not sure if these are still made, but either way it would probably be preferable to lose it altogether and rejig the pipework as necessary to negate the need for it.

That is a 3 port valve, the W end of the sticker is missing! Following the pipe from the W port, it tees off, and goes down to feed the cylinder coil, where does the upward leg go to?

 

[Hitmo]

Hi Hugh, thanks for all your help. In the end I decided it might be better if I stuck to my day job and called out a pumber! He came to the same diagnosis as you and will be removing the aerjec, rejiging my pipework and doing a power flush.

Thanks to all your help and advice on this, if nothing I learnt the difference between a 2 and 3 port valve!