CH pipework query

[richie4236]

I'm trying to get my head around our CH system and while I think I get most of it, I'm a bit stumped by one or two features. I've labelled the pipes and the bits I'm curious about. Hopefully, someone can explain.

1) Is the expansion for the hot water? Lower down is a T which goes up and down. Up goes through into the loft then turns and drops over the main CW tank.
2) Is the main pipe out of the CW tank? This just drops into the floor. There's another identical pipe on the opposite side which feeds the cylinder.
3) Is the mains supply from downstairs. It goes into the loft, then T's off to feed the main CW tank, and the CH header tank.
4) Is fed from the CH header tank. I presume this keeps the rads topped up somehow.
5) Appears to be another expansion pipe, this time going right to the top of the attic and then turns and drops into the CH header tank.
6) What the hell is this?
7) This comes off the top of the pump.
8) I'd always assumed this merged with 7 in whatever 6 is, and both went up as 5, but having chased 5 to the header tank, I'm guessing 8 is the return to the boiler.

Any explanation is appreciated. I'm not about to start messing with the CH system, but I'd like to know what it's all for. Thanks.

(I wrote on the walls, so that might be wrong).

 

[danfre]

Air seperator

 

[Exedon]

Myson aerjec try sticking a magnet on it often full of crap.
Work of the devil.

 

[fixitflav]

I'm trying to get my head around our CH system and while I think I get most of it, I'm a bit stumped by one or two features. I've labelled the pipes and the bits I'm curious about. Hopefully, someone can explain.

1) Is the expansion for the hot water? Lower down is a T which goes up and down. Up goes through into the loft then turns and drops over the main CW tank.
2) Is the main pipe out of the CW tank? This just drops into the floor. There's another identical pipe on the opposite side which feeds the cylinder.
3) Is the mains supply from downstairs. It goes into the loft, then T's off to feed the main CW tank, and the CH header tank.
4) Is fed from the CH header tank. I presume this keeps the rads topped up somehow.
5) Appears to be another expansion pipe, this time going right to the top of the attic and then turns and drops into the CH header tank.
6) What the hell is this?
7) This comes off the top of the pump.
8) I'd always assumed this merged with 7 in whatever 6 is, and both went up as 5, but having chased 5 to the header tank, I'm guessing 8 is the return to the boiler.

Any explanation is appreciated. I'm not about to start messing with the CH system, but I'd like to know what it's all for. Thanks.

(I wrote on the walls, so that might be wrong).

View attachment 320136

My take is :-
1) Yes. The down pipe is to the HW taps.
2) Yes. Through the floor to the CW taps, and I assume branches off somewhere for cold feed to the HW cylinder.
3) Yes.
4) Yes, cold feed. It normally goes after the open vent pipe 5, not more than 150mm downstream, but maybe it's OK with the separator 6..
5) Correct
6) See #2 and #3.
7) OK
8) Goes through the rads first, then returns to the boiler.

You haven't mentioned the HW to the cylinder primary. Do you have a 3-port or two 2-port valves?

 

[fixitflav]

On 2nd thoughts, more likely

8) from the boiler (flow)
7) to the pump inlet (and from the pump to the rads). Pumping downwards, which isn't ideal.

Can't be sure without seeing more of the system. Can you confirm?

 

[richie4236]

On 2nd thoughts, more likely

8) from the boiler (flow)
7) to the pump inlet (and from the pump to the rads). Pumping downwards, which isn't ideal.

Can't be sure without seeing more of the system. Can you confirm?

Thanks for the response. Additional picture below.

7 does go the pump, and I confirmed with the arrow on it's side that it's pumping down. Forgive my stupidity, but why is this a problem? From the LEDs and control panel on the front, it looks like this is the correct orientation?

Cold water that feeds the cylider comes down on the opposite side of the AC and is fed direct from the CW tank with a single isolator in the pipe and a drain at the lowest point.

There seems to be a hell of a lot of air in the system. I bleed one particularly noise rad every couple of weeks. This suggests to me that the air separator isn't doing it's job. It's hard to say how old the system is. The house was built in 1990, so possibly 33 years. I'm guessing that's pretty old for an air separator?

 

[richie4236]

Myson aerjec try sticking a magnet on it often full of crap.
Work of the devil.

We've got one of these from when the a new boiler was fitted a few years ago. Shouln't that pull all the magnetic crud out of the pipes?

As I mentioned in another post, there's a lot of air in the system, so I assume the valve isn't doing it's job? Will sticking a mag on it help, or should I be looking to replace it entirely? It could be as old as 33 years bas ed on when the house was built.

 

[fixitflav]

7 does go the pump, and I confirmed with the arrow on it's side that it's pumping down. Forgive my stupidity, but why is this a problem?

Pumping downwards is possible, but it's generally considered undesirable (in industry in general, not just heating). Mainly because any air bubbles get through the pump better if it's upwards.

There seems to be a hell of a lot of air in the system.

Are you sure it's air? Try lighting it, if it burns it's hydrogen.
Is the inhibitor up to strength? Worth doing a wire nail test as in attached thread. https://www.diynot.com/diy/threads/how-much-inhibitor.618592/

This suggests to me that the air separator isn't doing it's job.

I've never had one so don't know. Is it possible to dismantle it and clean out any crud?

 

[richie4236]

Pumping downwards is possible, but it's generally considered undesirable (in industry in general, not just heating). Mainly because any air bubbles get through the pump better if it's upwards.

Are you sure it's air? Try lighting it, if it burns it's hydrogen.
Is the inhibitor up to strength? Worth doing a wire nail test as in attached thread. https://www.diynot.com/diy/threads/how-much-inhibitor.618592/

I've never had one so don't know. Is it possible to dismantle it and clean out any crud?

Hydrogen seems very unlikely, but as I let about half a radiator of gas out the other day, I'm definitely not going to try igniting it to see what happens.

Thanks for the pointer for testing the inhibitor. I've got that going on now, but as the system hasn't been drained and refilled for a really long time, I'm guessing it's going to need more.

The air separator is a sealed unit. The domed top is welded to the plate at the bottom and it doesn't appear to be serviceable in any way. I've stuck a bloody great magnet on the top to see if that helps clear it a bit.

 

[ianmcd]

We've got one of these from when the a new boiler was fitted a few years ago. Shouln't that pull all the magnetic crud out of the pipes?

As I mentioned in another post, there's a lot of air in the system, so I assume the valve isn't doing it's job? Will sticking a mag on it help, or should I be looking to replace it entirely? It could be as old as 33 years bas ed on when the house was built.

View attachment 321142

That is a magnetic system water filter and has absolutely nothing to do with air

 

[fixitflav]

Hydrogen seems very unlikely, but as I let about half a radiator of gas out the other day, I'm definitely not going to try igniting it to see what happens.

If there's been little or no inhibitor in there for a few years hydrogen is a possibility. No need to worry about lighting it, if you put your thumb over it it will go out.

 

[richie4236]

That is a magnetic system water filter and has absolutely nothing to do with air

Thanks. I get that, but if the filter hasn't been emptied for a long time then presumably the sludge it hasn't removed could block the separator.

 

[fixitflav]

if the filter hasn't been emptied for a long time

Then empty it dear Liza, dear Liza, empty it!

 

[richie4236]

Then empty it dear Liza, dear Liza, empty it!

done. there was a lot of sludge in there. All magnetic. I don't think we got it all out, but we must have pulled 10 litres out of the system and I wanted to let it refill, so will have another go today.