Heating fine but water only luke warm

K.Flyer

MuddyDog wrote: »

Is this it circled in red? The orange pipe is the flow from boiler. Yellow is the coil flow to the cylinder. Blue is the coil return from the cylinder.

Yes, that's it, it's closed, leave like that for now.
Any signs of the othe valve anywhere on the return pipe?

MuddyDog

https://ibb.co/kDJFBNG

Yes. Blue is the coil return pipe. Yellow is the pipe from the pressure gauge that joins it. The red circled valve is turned fully to the right (closed)

K.Flyer

Another thought.
Take the white actuator off the valve give the spindle a few twists, make sure it's moving freely.
Actuator may be faulty, take one of the other actuators (e.g. upstairs zone) and fit it onto the HW valve and turn on that (upstairs) zone from your controller and see what happens.

MuddyDog

What's actually the purpose of that little pipe connecting the boiler flow to the coil return as well by the way?

MuddyDog

Actuators were replaced 4 months ago. I can hear them opening and closing when I activate or deactivate the water or CH. Also wouldn't the coil flow into the cylinder be cold if it wasn't open fully? At the moment it gets too hot to touch but it's just around this point the boiler will shut off.

K.Flyer

MuddyDog wrote: »

https://ibb.co/kDJFBNG

Yes. Blue is the coil return pipe. Yellow is the pipe from the pressure gauge that joins it. The red circled valve is turned fully to the right (closed)

Ok, let's try make sure we are on the same page here..
Is that valve the only valve on the return line other than the connection for the gauge and probably the filling valve?
Return from the cylinder goes around to the back of the cylinder and is connected to that valve and then into beige pex pipe and no other connections other than the gauge connection?

K.Flyer

MuddyDog wrote: »

What's actually the purpose of that little pipe connecting the boiler flow to the coil return as well by the way?

It's a basic bypass valve set up, very basic.
You really should have a spring loaded automatic by-pass valve fitted there. It was a cheap shortcut on materials but the same work involved.

MuddyDog

https://ibb.co/7CqCFv1

Looks like it.

Blue line is the pipe leading down from the pressure gauge. Above pressure gauge is the valve for water which is closed fully now as it says 2 bar.
Green line is the coil return from the cylinder. In the previous pic it did look like it connected to a beige pipe after the red valve but as can be seen above that beige pipe is a different pipe entirely and the coil return pipe continues off down into the floorboards and I assume back to the boiler?

MuddyDog

K.Flyer wrote: »

It's a basic bypass valve set up, very basic.
You really should have a spring loaded automatic by-pass valve fitted there. It was a cheap shortcut on materials but the same work involved.

Thanks. I couldn't understand the logic of it alright. So if it's on what is it bypassing? Currently it's off obviously so when it's off its essentially like the pipes are not even connected right?

K.Flyer

Ok I see, it's going into a copper pipe not pex.
Is that 1/2 inch pipe on that valve, hard to tell from the picture.

MuddyDog

Yes looks like a half inch copper pipe as the other copper pipes are slightly bigger (3/4 inch)

K.Flyer

If, as you say, that is the only pipe from the coil return and that valve is on the run back to the boiler, then how can the water flow back to the boiler to be re-circulated if that valve is shut?
Do you know of any reason why it was closed?

MuddyDog

Not sure. I don't think it's ever been opened.

MuddyDog

The only other thing connected to coil return is the red expansion vessel in my earlier pics

John.G

May be worth ensuring the motorised valve is closed then slacken the flow connection at the cylinder and pull back the pipe, if water stops flowing then obviously some valve closed on the return or some other obstruction or simply air which should escape when you break that top connection.

MuddyDog

I've opened that valve KFlyer and should know soon if that's the problem.

MuddyDog

Return is getting hot now. No idea how or why that valve became closed! Hopefully that's that! Thanks Flyer and John!

K.Flyer

It may have been partially open, but if the system is dirty it may have clogged with hardend sludge.

It's very difficult to fully assess your pipework from the pictures as it is very untidy.
Can you see the 1/2 inch pipe coming through to the ceiling towards the boiler and is it connected?

From the information that you have given me I am of the opinion that this valve is the balancing valve on the coil return, but I may be mistaken, and it would need to be opened to find out.

You could try opening it a full rotation. You should hear / feel some water passing through it, but not too much as pressure balances on both side of the valve.
Watch the pressure gauge as you do it, you may see a drop but usually not a complete drop.

Maybe as a precaution, have someone under the ceiling below watching and listening for leakage as you do it.

K.Flyer

MuddyDog wrote: »

I've opened that valve KFlyer and should know soon if that's the problem.

MuddyDog wrote: »

Return is getting hot now. No idea how or why that valve became closed! Hopefully that's that! Thanks Flyer and John!

Ah grand, you did before my last post.
Let it run for a while, monitor your pressure gauge while the system gets up to full temperature.

MuddyDog

But if that valve isn't fully opened then how does the water flow back to the boiler to get reheated? Why would we only want it partially open?

K.Flyer

MuddyDog wrote: »

But if that valve isn't fully opened then how does the water flow back to the boiler to get reheated? Why would we only want it partially open?

If you have all of your zones switched on the flow of water will follow the path of least resistance.
Usually that pipe is 3/4 inch and if the valve is fully open the water will circulate through that route much quicker than the rest of the system.
As such, when that section gets up to full temp the hot water returned to the boiler will activate a temperature sensor in the boiler switching off the burner, but the radiators are still nowhere near warm.
Buy closing down the valve to the correct position it forces more heated water through the radiator circuits giving a balanced feed to all radiators as well as enough to the cylinder coil.
That's why it is beneficial to have a clean and well balanced system for everything to heat at an even rate.
But all of that is at the mercy of the system being plumbed well.

MuddyDog

Makes sense. Funnily enough in our badly plumbed system it might be a good thing that it's fully open because usually having only HW on also heats the Rads in the extension we did a few years ago meaning the HW would heat slower than it probably should and now after this I assume the HW will get hotter faster. Only becomes an issue obviously when HW and CH are on but that's quite rare in our household anyway.

K.Flyer

What you could try is turn off both heating zones and the new rads in your extension.
Rotate the valve fully closed then open it about 1.5 rotations.
Turn on H.W. zone and start to slowly rotate the balance valve towards closed. Listen carefully for a change in the tone of the water passing through the valve and stop turning, this may take a couple of attempts to get right.
Now rotate the valve to try find the point where the noise is starting, when you have, rotate a 1/4 turn towards closed and see how that affects everything.
Later you may need to make a slight adjustment to open more if the hot water is taking too long to heat, but it is close to a good rule of thumb position.