I thought the pictures looked familiar, you posted back in May of last Year asking for advice on something to do with this set up, but I cant find the Thread now. Didn't you make some alterations back then?
Hot water temp is 40 Degrees - Ideal Mexico 2 Boiler
- Thread starter JackK
- Start date
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I am so sorry you took it the wrong way - I just wanted to be super sure that my understanding was correct
You have bee invaluable in helping nail down the flow issue with the bended pipe and I am really appreciative
I really did not mean to offend - If you could please continue to give me guidance I would appreciate it
The other option might be to get a bespoke cylinder made to fit your situation. I know this one is almost brand new, so probably not something you want to do. But have it made with a gravity coil and have the flow go into the right hand side so you avoid having the loop over. Keep the return on the left. That would presumably be more like the original one you needed to replace. Obviously, get professional advice first!!
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The original cylinder probably had an annulus inside it ( love that word) The large opposite tappings give it away. So a new one would need at least a 28mm coil inside. Possibly controlled by a Cyltrol valve on the return - if they even still make them.
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I had no idea! So had to Google. Is there anything inside the annulus (apart from the system water!) or is it just an empty cylinder?
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I know nowt about gravity systems, and I've not read the entire thread, but wouldn't adding a pump - instead of relying upon gravity - fix it quicker and at less cost for the OP, rather than swapping the cylinder?
The pump might disturb the one pipe system and cause other problems
i am going to dry to bend the flow pipe downwards so gravity can push water into the coil - I know nothing about this subject and work in IT so I am probably wasting my time
Failing that I am going to look at running a new dedicated flow pipe from the boiler to this cylinder
I have lived in the house for ten years and never completely understood how the system works - I found out it was a one pipe system only a year ago - I feel so foolish and gas engineers who have come have not noticed either
i am going to dry to bend the flow pipe downwards so gravity can push water into the coil - I know nothing about this subject and work in IT so I am probably wasting my time
Failing that I am going to look at running a new dedicated flow pipe from the boiler to this cylinder
I have lived in the house for ten years and never completely understood how the system works - I found out it was a one pipe system only a year ago - I feel so foolish and gas engineers who have come have not noticed either
This is exactly what I advised back in April last year original cylinder was a cross flow I advised purpose made cylinder.
However op decided butcher in an off the shelf solution and 10 month later job still in a mess.
I should have done that yes - I am sorry about that
If I take off the flow pipe and put in bucket how many litres a minute should i get into the flow pipe so I can measure the flow speed
Are you in agreement that rebending the flow pipe downwards wont work - I am trying to clutch at straws I know
Thank god I was not talked into putting in a n unvented cylinder
Taking off the flow pipe will not give tou any idea of the circulation rate as you will lose any syphon head from the system.
If we are talking about a gravity hot water system, if you do not wish to adapt to fully pumped, than you will need to have a cylinder specially made.
If it helps to narrow my options this is the old culinder
I am confused because I thought I have fully pumped already. I have a pump on the boiler return which shoots water up the white flow pipe and the hot water is the first tee of that
Would a more powerful pump replacement make any difference or am I kidding myself
Your one pipe system obviously does use a pump, but it is not "fully pumped" in the sense that heating engineers would use that phrase. Neither is it a "gravity" system in the sense that phrase is used.
You might be relying too much on a comment I made, really as an aside. @DP's suggestion of trying a pump where the motorised valve currently is sounded very logical. I wouldn't want anything I wrote you to divert you from what might be an easy solution.
Thank you - I think this is my problem - I do not know the terminology used for my system to research what I can do -
I wish I would have repiped the system in 22mm speedfit pipework but I have just redecorated the whole house sadly and I dont have the money left to that - I wanted to change my boiler to another Intergas heat only boiler but I am too scared to do that
I think your system is quite unusual and it might be difficult to know what to search for.
The following bit is nothing to do with it being a one-pipe system. It is just an explanation of "gravity" and "fully pumped" systems
In the old days, two separate flow pipes would come out of the boiler. One flow pipe was pumped through all the radiators, before eventually returning to the boiler, in the central heating return pipe. The other flow pipe went up to heat the cylinder, but it wasn't pumped. The hot water would rise up to the cylinder by convection and then, when it had cooled after passing through the cylinder, it would fall back down to the boiler in the hot water return pipe. So, this setup was called a "gravity" system. And there were four pipes in total at the boiler, two flows and two returns.
Then in the 1980s, I think, we moved to a different set up. Only one flow pipe would come out of the boiler. It would pass through a pump and then would immediately be split by a zone valve (or valves) into two circuits. One circuit would be pumped to the radiators as before. The other circuit would be pumped through the cylinder. So that system is called "fully pumped" because both heating and hot water circuits are pumped. There is just one flow and one return pipe at the boiler.
Your system is different. Only one flow pipe comes out of the boiler and then, halfway around the main circuit, it tees off on a loop which passes through the cylinder before rejoining the main circuit. The cylinder effectively seems to being treated as if it was another radiator. I have no idea how common your type of system used to be. I know you are wondering why the water is not being "pumped" through the cylinder and that is tricky I think to understand and explain. I think the answer is that the cylinder loop is rejoining the exact same pipe very close to where it left it. So, there is no pressure difference between where it tees off and where it rejoins so there is nothing to force the water through the cylinder.
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