No hot water

The auto release thing was fitted by the plumber along with he stop cock,it is a very old system,we have several redundant pipes that were disconnected and just left in situ, we have a 3rd tank (empty)in the loft that suffered the same fate. A Rayburn also existed and heated water. None of this is relevant but wanted to show confusing it is to explain it all.
I don't understand how the hot water worked when selected with only one motorised valve that is either open or closed, the plumber spent nearly six hours before giving up,he gave us a substantial discount and only charged for two hours. He is sort of convinced there is a blockage in the coil,but quoted another four to five hours with no guarantee of success. When my ribs and finances recover, I will try and see if there is any water in the coil. Again thanks for all your help gents.
 
cnikon said:
The auto release thing was fitted by the plumber along with he stop cock
Click to expand...
If water comes out of it, if necessary after undoing something, that clears up the airlock issue.

cnikon said:
I don't understand how the hot water worked when selected with only one motorised valve that is either open or closed
Click to expand...
There's no reason why it wouldn't work, if the Tapstat is working properly and the coil is not blocked. With the motorised valve open there should still be enough flow through the coil. If the timer is not calling for CH the motorised valve should be closed, but it sounds like it's not working properly. If you can make sure it's closed, manually if necessary, that gives best chance of getting flow through the coil.
 
I haven't read every post , so apols iff... ....

You can't manually close the Honeywell zone (metal topped ) valve.
There's a rubber ball in it which moves against a circular orifice to block flow.
The electric motor moves it away from the orifice, and a spring returns the valve to shut it, which opens a switch - typically turning a pump/ boiler off.
The rubber ball can get stuck or distort, or expand so it blocks pretty much everything, open or shut, but more often the electric motor just packs up.

If it's just the motor dud, you can tell because the spring will have returned the valve to he closed position, so if you try to move the lever ( which should be UNhooked) you'll feel a spring-through-gears pressure. If you keep pushing, (whizzy noise) you can lock it half open, but that won't close the electrical switch.
To clarify, for the switch to close, the valve has to be fully opened by the motor, you con't do it manually. If everything is free of resistance (as when new) you can get the switch to momentarily close by pushing hard on the lever. Momentum in the gears will take the internals past the hooked point, and the switch will close ( you may hear something start up). Then the spring will take over and bring the internals partway back (assuming you hooked the lever), and the switch will go open again. (pump or boiler , will go off)
So, to repeat, if you push the lever very hard, you may hear the pump start then stop a second or three later.


T'other's a Drayton Tapstat valve.
Here, have some useless data sheets.

temp save...

You should be able to undo the knurled collar:
1683499500722.png

Now I'm guessing, here, because I never took exactly one of those apart, that like the rad valves there's a pin in there which is supposed to stay out about 5mm until pressed by the "head". If it's stuck down (likely, the rad valve equivalents do it a lot) then use a toffee hammer to bash the valve, tap the end of the pin etc etc it could unstick itself, etc. Don't pull the pin because it'll pee water out.
The Tapstat presumably can fail either way. If the mechanics in the part which is like a radiator valve sticks, pin stuck in, the valve will be shut. If the expanding liquid sensor part fails, the valve will stay open because the expanding liquid leaked away and never presses the pin inside..
Google "stuck thermostatic valve", to see pins aplenty.

£185 or whatever I just saw is a silly price, you could get a (a second zone-type ) electric valve and cylinder thermostat for loads less than that.

(The 28mm valve in tis pic has funny pipe conns, most are just normal compression.)

HTH

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Justin Passing said:
That's a Drayton Tapstat valve. They can fail either way. If the mechanics in the part which is like a radiator valve sticks, the valve will be open. If the expanding liquid sensor part fails, the valve will stayclosed.


temp save...
Click to expand...
So, maybe the pin should be kept pressedin/down with something to see if water starts flowing through the coil in case the capillary has lost its fluid, I'm surprised that it fails closed (on fluid loss) since the liquid expands as the cylinder/sensor heats up.
 
Johntheo5 said:
I'm surprised ...
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Ang, on, maybe it's me wrong on that last bit.... yes it is, sorry.

Yes you're right If the pin's stuck in you get no HW, , the heat should push the pin in to stop the flow to stop HW getting hotter :rolleyes:. So if the expanding liquid leaks it'll stay open. I changed that about 3 times, it must be the Crème de menthe from celebrating the new king going to my head......
(Lies, I didn't watch it, but I can't think of a better excuse. I should be on benefits at my age you know...)

I'll edit the post....

If you're averagely lucky, tapping the pin a few times will release it. If you start undoing things, you'll get wet, but you may have to.

There used to be similar valves to yours at sensible prices, but they seem to be unusual now.
 
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The upper pipe is getting hot all the way to where it enters the cylinder,well past the Tapstat which has had the head removed completely,the pin is extended about 5mm, the pipe enters on the opposite side of the cylinder which would suggest it's clear up to that point.
I think I will have to undo the lower pipe without flooding the house somehow!
 
Sounds very much like air in the coil to me. Especially seeing as you've recently had a powerflush.
 
Also check for a wheeltype gate valve on the coil return close to the cylinder, these are often installed for balancing purposes, if installed shut it fully, then reopen it fully, should take ~ 3 to 5 full turns to fully open it, you can allways throttle it in later, if required.
 
There is one of these that its pipe goes back to loft, the other end goes under floorboards, another one seems to come off pipe from top of cylinder, I shut and opened that one,it was already hot both sides,(immersion has been on)
 
Is there a valve on the return pipe from the cylinder coil before its teed in anywhere else?. If so, check that its fully opened by fully closing it, then fully reopening it.
 
Don't think so, if there is,it's been placed where no one can see or operate it, unfortunately that is not as ridiculous as it sounds. think I need someone to actually see it, as I am not that good at explaining it all. Thanks for your persistence!
 
This is where it gets hot
 

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This whole pipe gets hot
 

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Is the horizontal pipe in the left photo the coil flow and if so, is this hot?.
Is the pipe in the right photo, the coil return and is this cold?.
 
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