No hot water - Unless central heating also on

[se99paj]

I've been having an issue with my hot water in the last week.

Essentially the hot water has stopped working, the timer is working correctly, but the boiler never turns on and the water doesn't get heated.

The only success I've had is to turn on the central heating at the same time, this allows us to use the hot water, but it does mean fiddling with the thermostat whenever we want hot water.

The motorised valve has been suggested as the fault, but there are only 3 in my airing cupboard and none of them are related to the hot water as far as I can tell. Two of them are on the central heating pipes and one of them is connected to the solar powered heating system.

I assumed the solar powered heating system is a closed system and won't have any affect on the hot water, it just takes water from the panels into the water tank. Although I'm not sure if the motorised valve is working correctly as the switch is lose.

I have an engineer coming out on Tuesday but any advice on things to look at what be great.

Thanks in advance

 

[D_Hailsham]

Can you post a pic of the airing cupboard? We need a general view - not close ups - so we can see how everything connects together.

 

[se99paj]

Thanks for the reply - I've uploaded some photos, some are a general view and some are close up.

I did try and draw a technical drawing, but it gets quite complicated quite quickly in the cupboard. I can still give it a go if you think it would be useful, might look amateurish though.

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• se99paj
• 19 Oct 2014
• 1

Untitled

• se99paj
• 19 Oct 2014
• 1

Untitled

• se99paj
• 19 Oct 2014
• 1

Untitled

• se99paj
• 19 Oct 2014
• 1

 

[manortim]

3rd pic from left. the metal box that that is on the pipe that leads into the cylinder.

its faulty.

needs to be replaced. you can get just the head on its own and simply remove/refit it.

 

[se99paj]

Thanks for that - think I'm starting to figure out how it all works.

Because that valve is failing and I have the central heating valve open the hot water from the boiler is going through the primary coil and the central heating loop, which in turn gives me hot water.

It the valve was working correctly the central heating valve can be shut off and the hot water from the boiler only goes around the primary coil. Which in turn heats the hot water in the cylinder and I get the hot water.

 

[se99paj]

Had a guy come out to check the plumbing the other day and after checking the components the problem seemed to be caused by a loose cable.

I left the hot water on whilst I went to work for the afternoon and came back and everything was working correctly, I then switched the hot water back to the timed setting.

But the hot water never came back on with the timed setting, even if I tried to use the boost option or on permanently, nothing happened.


I managed to get some hot water this evening using the central heating trick, when the hot water got hot enough I switched off the central heating and left the hot water on. This is working without a problem now.

It seems that once the water in the cylinder is hot enough the hot water will work correctly, but from cold the hot water never comes one.

I'm going to give the plumber a call tomorrow and get them back to have a look. But interested to hear any ideas what could be causing the problem.

Just to add I've done some testing tonight, on the boiler there is a digital temperature gauge, this is the hot water temperature, guessing the hot water in the boiler not the cylinder.

After getting the water to 65C I put the timer to "On", the temperature dropped to 58C after 10 minutes then the boiler kicked in back to 65C, this happened pretty much every 10 minutes like clock work. I then changed the setting to "timed" the temperature took almost an hour to drop from 65C to 58C, but the boiler didn't kick in and the temperature kept dropping. I switched the timer back to "On" but the boiler won't kick in.