Heating Plumbing Mess - Advice Needed

Xeorix

Hi All,

We had a new boiler fitted a few months back, and after a nightmare getting it up and running, everything was finally working.

That was until we drained the system to continue refurbishments, and we also removed the ceiling where the old boiler was.

To cut a long story short, the plumbers fitted the new boiler in a new location, and replaced the header tank in the loft with an expansion vessel (we'll get onto that later). We went to fill the expansion vessel in the loft, only to find it reporting 1.5bar, despite being empty.

The original plumbers who fitted it replied to 2 of my emails with short one liners, and have since stopped responding all together. Time to call in a local plumber!

To put it simply, the pipework is all wrong and we can't find a plumber who will fix it, so we're going to do it ourselves. We've had plenty of experience with plumbing, but not on this scale so just wanted to check our logic first.


After the boiler move, removing the ceiling and only having the hot water on, I noticed the 2 radiators on the right side of the drawings were getting hot. Looking at the plumbing, it looks like we've got reverse flow. Also, I noticed a leak thanks to the build up of pressure around where the old boiler was - the plumbers replaced the old boiler with a valve as per:



Now it's time to fix it. From what I can gather, originally the 15mm was the last pipe in the chain, however now it isn't. So by logic, I need to replumb this pipe to be the last in the chain, and ensure the water is flowing the right way, however I've come up with 2 ways of doing this.

The first is by rerouting the 15mm from the cylinder straight to the boiler as so. My only thought with this is that water is flowing against each other to a T junction, not sure if this will cause issues:



The 2nd option is to remove the value, and plumb this directly back to the boiler as the return like so:


If anyone could give me some pointers, that would be greatly appreciated!

andyhop

To be blunt you have no idea. I'd suggest getting another tradesman to inspect and correct any faults

Expansion vessels have a diaphram, regardless off if you have drained the system it will have pressure on the dry side of the vessel, its designed like this to allow for expansion in the system

Xeorix

andyhop wrote: »

To be blunt you have no idea. I'd suggest getting another tradesman to inspect and correct any faults

Expansion vessels have a diaphram, regardless off if you have drained the system it will have pressure on the dry side of the vessel, its designed like this to allow for expansion in the system

The gauge is knackered. We took it off and it still shows 1.5bar

Ectophile

The "After" diagram seems to make no sense. Assuming "P" is a pump, then all the pump does is pump water from the hot side of the boiler to the cold, without it going through any radiators.

I can't see any difference between "New" and "New 2" except that you have drawn the latter with longer pipes. There's no pump in those diagrams. That will only work if the boiler has a built-in pump.

Xeorix

Ectophile wrote: »

The "After" diagram seems to make no sense. Assuming "P" is a pump, then all the pump does is pump water from the hot side of the boiler to the cold, without it going through any radiators.

I can't see any difference between "New" and "New 2" except that you have drawn the latter with longer pipes. There's no pump in those diagrams. That will only work if the boiler has a built-in pump.

There is no P in any of the diagrams. It's a Y plan system and the pump is right before the valve (V) If you mean the valve, then this is where the old boiler was. They joined the old flow and return pipes using a valve, which means that the original flow (which is now part return) is connected to the new flow, prior to it hitting the pump

New - has water flowing from the left, and from the right to the T junction where the return to the boiler is

New 2 - has water flowing the same way down all pipes

Ectophile

OK, so the thing I assumed was a pump wasn't.

But I still don't see any difference between New and New2 other than the lengths of the pipes. I'm not sure what you mean by "My only thought with this is that water is flowing against each other to a T junction" - there are lots of T junctions, and I don't see anywhere where there would be a problem where the water wouldn't know which way to flow.