Why would my oil boiler not heat water too?

[Paulone]

Have just rented a house that has oil heating. We have had the heat on for the last couple of evenings and find that the system heats the rads fine, but not the water in the cylinder.

There is a separate control on the time clock for water heating that we have been told does not work - if we want to heat water, the advice was to run the full system and switch off the radiators. This didn't work and we've been resorting to the immersion heater.

The boiler and other aspects of the system all seem quite normal and not very old. the house is not very big either.

Thinking about the cost of oil and our carbon footprint - we'd love it that the heat worked for both water and rads. Before I start asking for it to be investigated, does anyone know if a system would ever be installed where the radiator and water heating would be completely separate or is there any kind of a fault that would cause water to remain cold?

 

[irishlinks]

There could be a valve that controls the flow to the hot water tank that has been turned off. Have you not asked the landlord - it should be their responsibility to get the hot water working ?

 

[DavyJones]

Hi, Check your hotpress and look at cylinder. You will see two pipes sticking out of it about 18" apart and parallel, you should see a valve with a red round handle, turn it anti clockwise(lefty loosely, righty tighty!) to ensure it's open. this valve is used to balance water flow and should be half closed when everything is working right. If thats open, check for a valve that has a box on it and a cable running from it (its a motorised valve) you may have two, 1 for heating and 1 for hot water. When these things go wrong their default position is off.
Once you have found it there is a little lever on the side, you may have to run your fungers around it to find it. when you locate lever pull to the side and when you can't push it anymore press up and it should fit into a little grove and remain open. I.E you have manually overidden motorised valve. The valve may need to be replaced but this should give you hot water for the time being.

 

[davidoco]

There is a separate control on the time clock for water heating that we have been told does not work - if we want to heat water, the advice was to run the full system and switch off the radiators. This didn't work and we've been resorting to the immersion heater.

Sounds like a zone valve is gone bust which would open the route to the hot water cylinder and fire the boiler. Probably best that you insist on the seperate control working the hot water (without resorting to turning off all the rads).

Building reg states for the past at least 7 or 8 years that you must have seperate control.

 

[bacchus]

There could be a valve that controls the flow to the hot water tank that has been turned off.

I thought this was the only flow that was not controlled in an installation as it is usually the main return to the boiler (and the only one when all radiators are turned off)?

 

[DavyJones]

I thought this was the only flow that was not controlled in an installation as it is usually the main return to the boiler (and the only one when all radiators are turned off)?

Depends on installation and number of zones. If cylinder is zoned there is a by-pass near the boiler to ensure no pump damage if system operates with all zones closed.