No hot water but heating working fine

Discussion in 'Home energy' started by Poozie, Jul 4, 2011.

  1. Poozie

    Poozie Guest


    This is my first ever post so go easy with me.... Basically I had the rads turned off because obviously in summer I only need my gas boiler to heat the water and not the rads.. all was fine until my housemated decided she wanted the heat on and decided to mess around with a few of the levers in the hot press... So now I have no hot water going to the taps or shower (as in there is water its just luke warm) but the heating is working fine... some of the pipes in the hot water cylinder in the hot press are roasting while others arent hot at all... I havent a breeze whats going on but I do recall that the pipe on the top of the cylinder should normally be hot and at present it isnt... theres all sorts of inscriptions where the levers that she messed with are like "Cold to Shower" and "cold heating" but its lost on me whats what and which way the levers should be going... can anyone shed some light on whats going on?

    thanks a mill
  2. mradaly01

    mradaly01 Frequent Poster

    A few things....
    - Your gas boiler heats rads & waters? (no separate system for either heating)
    - Is the heating zoned (separate settings on the gas boiler for water only, rads only, water and rads together) ?
    - Were the levers only turned on the pipes around the hot water cylinder or at the gas boiler also?
    - when you say "rads were turned off" - was that at each radiator or just flow to the radiators (or rad zone at the boiler itself?)

    When the heating is on (set to heat water & rads) - is there a pipe into the cylinder that is hot - if not, trace that back - is there a lever on that pipe? is it warm above the lever, but not below it? If so, turn the lever & leave a while.

    Is your cylinder pre-insulated or just a tie around insulation. Is the water in your cylinder heating up?
  3. peteb

    peteb Frequent Poster

    Is it a gas boiler and you are after putting too much water in the system? What does the pressure on your boiler say? Is there water pouring out of your overflow pipe?
  4. OMC FIX

    OMC FIX Registered User

    If you have a copper cylinder and you have cold or luke warm water coming from water coming from the hot taps? Try the following (1) on one side of the cylinder there should be two copper pipes entering the side of the tank at approx 1/3 and 2/3 of the height of the tank. If so, one of those two types comes from the gas boiler with hot water enters a "coil" inside the cylinder, exchanges heat with the cold water in the cylinder and then leaves the cylinder to return to the boiler. Often there is a valve with a wheel on it on one of those pipes to regulate the flow of hot water going to the cylinder and balance the flow of hot water going to the radiators. If there is such a valve with a wheel on top, open the valve (anti clockwise) half way (say 1.5 turns for now). Turn on the boiler and check that hot water reaches the cylinder from the boiler on one of the two pipes. (2). If not, is you hot water controlled by a time clock and thermostat or "zone controller" ? Is there a thermostat attached to the side of the copper cylinder by a spring (think of a white rubber band). If so, turn the thermostat up up approx 60 for now and with the boiler running check the two copper pipes again. Are the hot now ? If not, is check that the zone controller or time clock that calls up the hot water is set to "on" and with the boiler running check the copper pipes on the side of the cylinder again. Hot now? If not, there is a good chance your hot water is controlled by either a "motorised valve" or a manual valve where the Installer gave you the option to have hot water without radiators (summer for example) or to lower the costs of running the hot water and radiators.

    Let's begin with general statements, depending on the age of your home it could be either manual or motorised valves so IF you have a "zone controller" with on / off and boost for rads and hot water you probably also have motorised valves. If you have motorised valves look in the hot press for a "box" sitting on top of one or more copper pipes with an electrical cable attached. Also look above and below the gas boiler. The valve for the hot water is most likely in the hot press close to the two pipes already described entering the side of the cylinder. If there is such a device there will also be a little lever which will allow you to activate the valve manually and get the hot water circulating.

    If there is a manual valve in the hot press , open all valves for a time and with the boiler running identify the valve that needs to be open to get the hot water from the boiler to heat your hot water.

    Finally, if all of this fails l, you almost certainly have an immersion heater in the cylinder with an electrical cable going to a wall switch with on / off and sink / bath settings. Select on and sink to test the immersion and allow 90 mins for the heater to heat the water in the top section of the tank. Select bath to heat the full tank.
  5. Leo

    Leo Moderator

    I really hope they have resolved the issue at this stage!
    rob oyle likes this.
  6. OMC FIX

    OMC FIX Registered User

    Probably has alright but complaints about heating and hot water and the various controllers and valves are very common. Who knows, it may help someone else ?