No Hot Water

I have a problem with my Hot water, I will try to explain it as best I can but I am new to DIY so please bear with me.
I have tried to diagnose the problem as best I can but I am totaly stumped at what could be causing the problem.
The problem is as follows
The central heating is working (radiaters are warm) but I do not get any hot water. In the airing cupbard there is a tank and two boxes one with groundfos selectric on it (i think this is some kind of pump) and another box with Honeywell F4-9348 on it and a switch which is set to auto.
The oil boiler is working as it the pipes in the airing cupbaord are hot.
The funny thing is that there is a switch next to the two boxes above which if I switch it off and then switch it back on again I will get one tank of hot water.
Also the radiaters seem to be warm even if the thermostat is set below the temperature of the room in which it is in, I can turn the temperature down on room thermastat and the radiaters will still stay warm.
Everything was working fine before we went on holiday a week ago since then I have been having these problems.
I would like to fix the problem by myself if possible and I would appreciate any help that any one can give me, even if it is to say that you can't help me and that I should call a heating engineer out.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Sounds like it could be the zone valve. It seems not to respond to either the water requirement or the heating requirement from the stat.
The zone valve is the box with Honeywell F4-9348 on it. You can normally take the plastic box part off without having to disturb the pipework part of the valve. Provided the valve part itself rotates without much force, just put a new box on it. (It's called the actuator).
In the mean time, move the switch from "Auto" to the other setting "Both", "Manual", "Open" or whatever it describes itself as.
The switch that gets one tank of hot water could be for the electric immersion heater. Where do the cables from the switch go? Does turning it on cause your electric meter to go ballistic?
Christian.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

of
on
Thanks for the reply Christian, that makes sense I will try to get hold of a Zone valve and replace this over the weekend. the cables from the switch go to the pump and the zone valve. what will happen when I move the switch to "Manual"? do I need to replace the zone valve with the same model number?
The Immersion heater switch is on the other side of the cupboard.
Rob.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

OK. I have no idea what the switch does, then. If it has worked before, I'm not too worried. If it hasn't, then it could be some harebrained scheme to simply heat one tank of water at a time.

This will open the central heating and hot water circuits permanently, so if the boiler fires both will go on. Your hot water will probably get hotter than usual as the thermostat won't close off the circuit. Any rooms without TRVs will also get hotter. However, you do get heat and water.

You don't normally need the whole valve, just the actuator head. In fact, most manufacturer's actuators are compatible with each other. However, you have to choose the correct type. To find out if you only need the actuator, remove the plastic box and ensure the valve itself operates without undue force. You might also get some idea by how easily the override lever moves.
There are three main types of valve:
a) 2 port (i.e. on/off) b) 3 port diverter (i.e. A or B) c) 3 port mid position (i.e. A, B, or both)
You need to determine the correct type, although sometimes, (a) and (b) above share the same actuator.
Christian.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have opened the box and there is a cylinder with the word synchron on it, I guess this is the actuater. There are springs at the bottom of the cylinder and some wires going into it which go to the switch that I was explaining earlier.
if I turn the switch off the spring's move and it appears to close the water to the tank off, when I put the switch on the spring's move and it appears to turn the water onto the tank as I can hear the water rush through the pipes.
I think this is why it must give me one tank of water, then it goes to the off position and will not open up again.
Can I send you a picture so you can see what I mean?
How can I check the valve?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.