No Hot Water

[rules&rulers]

How long is the new horizontal pipe run ?
Is there any other horizontal run's ?

 

[GiveItAGoIain]

Rules & Rulers: About 2.8m, but exactly the same length as before, just in a different place.

 

[rules&rulers]

On the horizontal runs,As long as the flow pipe slopes upwards and the return slopes downwards then it should circulate although the length of 2.8m will not help. Maybe alter the slopes by undoing bottom elbow nuts,cut some copper pipe out to lower pipes.
It looks like a confined work area,hopefully there are not to many other elbows on the system. 2.8m is rather a worry.

 

[GiveItAGoIain]

There's not much I can do about the elbows. I can alter the pipework a bit more to help the slope, but as you can see, access is tight. It would be a royal pain.

 

[GiveItAGoIain]

So as there's no air in the system, have narrowed it down to flow of hot water to the cylinder? Anything else I can try?

 

[rules&rulers]

Thats how gravity works,then issues of air locks,other blockages can be fixed if required.
There is a possibility of an air pocket in one of the horizontal pipes,this would naturally vent away,can you confirm there is some slope on these pipes.(small spirit level helps).

 

[GiveItAGoIain]

No slope in the horizontal under the bathroom floor.

A rethink might be in order.

I could drop the pipes all the way down into the kitchen below and get a better slope behind the kitchen units.

Thanks so far everyone.

 

[ianmcd]

do you have an external drain down point for the Heating system and an outside tap ? if you do connect a hose between the two and open the drain cock and turn the tap on the mains pressure should force any air lock out , turn the tap on so the hose is full of water and not air before you connect it to the drain cock

 

[GiveItAGoIain]

Ianmcd: I assumed this wouldn't have an affect as there's separate flow and returns for hot water and heating from the boiler.

The original 'outside' drain down point was located under the dining room floor, now not easily accessible due to laminate floor. So I put a new one in a while back off one of the radiator spurs. Not quite the lowest point but better than nothing.

I've tried the hose trick through the vent by the F&E tank, along with venting the joins on the cylinder and the other high point.

So I could be wrong, but I don't think it's an airlock.

Thank you for replying... I am willing to try just about anything.

 

[GiveItAGoIain]

To top it all off, now my heating pump is running constantly.

Could my hot water issue be the boiler? Is there two separate parts on this boiler? Is the heat in the hot water pipes just conducted heat from the heating system?

 

[ianmcd]

wont work with the vent at the FE tank, put the hose on the draindown lockshield that you have fitted on the radiator and open it , what you are trying to do is fill the system from the lowest point and push any air upwards and out of the vent at the FE tank, we will deal with one problem at a time , once we get the HW working we will look at the pump problem

 

[GiveItAGoIain]

I'll give that a go!

 

[Agile]

When you backfill you need to keep an eye on the F&E tank. The over flow pipe might not accommodate all the water flow rate that you are adding.

You say there is no slope on the horizontal pipe.

Part of the operation of a gravity system requires a small slope so that air is naturally expelled.

The "head" on a gravity system is very small, perhaps just 100 mm if you are lucky and that's why it needs large bore piping.


Perhaps Sajeel can explain why you put PTFE tape on the compression nut threads?

Tony

 

[sajeel]

When you backfill you need to keep an eye on the F&E tank. The over flow pipe might not accommodate all the water flow rate that you are adding.

You say there is no slope on the horizontal pipe.

Part of the operation of a gravity system requires a small slope so that air is naturally expelled.

The "head" on a gravity system is very small, perhaps just 100 mm if you are lucky and that's why it needs large bore piping.


Perhaps Sajeel can explain why you put PTFE tape on the compression nut threads?

Tony

Haha very funny, i use joint compound something like water hark which is wras approved will be sufficient

 

[sbgasman]

In your picture it looks like the bottom pipe is falling ,not rising as it should.Might be angle of photo though.