No Hot Water - Vented System

[TheCat13]

Hi,

Hope some of you can help here.

I have a fully pumped indirect vented system and don't seem to be getting any hot water form the taps. The boiler is ok as is the central heating.

I am getting plenty of water, so there cannot be a blockage feeding the cylinder.

When I manually move the arm on the 3 port mid position valve, I then start getting some warm water. I can hear the valve moving and whiring, even see the arm moving. I originally thought the valve was at fault, is it?

The pipes feeding the coil in the cylinder seem to be quite hot and the thermostat is set at around 65 degrees.

Any ideas.

Thanks in advance for any help.

The Cat

 

[JohnD]

You are sure the pump is working properly, so it will pump round the rads but does not seem to be going to the cylinder?

is the cylinder quite high in the house? Is it above most of the rads?

If you bleed the highest radiator in the house, does water squirt out forcefully? Is this radiator higher or lower than the cylinder?

you say the primary feed to the cylinder coil is hot, what about the return pipe from the coil?

Have you been up in the loft yet to see if the F&E has water in it at about the right level, and if it is full of mud or dead wildlife?

 

[tryitandsee]

It may be just an air lock in the coil.

Try turning off the central heating (thus closing the three way valve to rad circuit pipework) turn up the speed of the pump, listen to the water circulating, as johnd says, you should be able to feel the pipes getting hot at both ends of coil pipework (anything really, to try and force any air lock out of the coil circuit).

 

[TheCat13]

Both pipes to and from the coil are hot, so I don't think there is an issue there (i.e. pipes coming in and out of cylinder)

I'm not at home at the moment, another bit of info which might help is this.

I had some new taps installed in the kitchen and the main stop cock was turned off and the cold water feed to the bottom of the cylinder. Could this have caused a problem? Air Lock etc..

Thanks

 

[JohnD]

yes, but the other possibility (esp. if the cylinder is high) is shortage of primary water, either empty or blocked F&E.

 

[tryitandsee]

If the coil is 'hot' at both ends then the water in the taps will be 'hot'.

This depends on what we are both interpreting/thinking is 'hot'.

Is hot, just heat transfer from the radiator circuit. I appreciate it does not help you not being there.
Either there is an air lock or the threeway valve is stuck on the central heating, or it may be just that your cylinder thermostat is not working.

 

[JohnD]

or maybe a hot tap has been left running (or a leak)

or a mixer has been fitted allowing cold mains water to pass up into the cylinder and the hot to be pushed out of the overflow of the cold tank

lots of interesting possibilities

 

[tryitandsee]

Spoken like a true Hampshire hog

 

[JohnD]

Hi, Scummer