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Thread: Electric heating - thermostats and programmers

  1. #1
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    Default Electric heating - thermostats and programmers

    Hi,

    I am looking to install an electric heating to replace warm air system. I have decided to install energy efficient infrared panels which just plug straight into a socket or more likely I will get them wired into a spurs however I want a decent control system that I can programme and that uses a thermostat.

    Anyone got any experience of these or recommendations?

    I have been looking at a few such as Honeywell, Heatmister or even Igreen.

    Cheers

    Garry

  2. #2
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    Default What is going on?

    We recently had a Honeywell wireless controller and thermostat installed in our boiler system. It has worked well for months. Then we found that the boiler was coming on at night (sometimes) even though the Controller was indicating that the boiler was off!
    This was put down to a sticking valve by the hot water tank... as the water cooled this triggered the boiler. It should then have been heating just the HW but the sticking valve caused it to heat the radiators, which is how we came to notice it.
    Now, here is my problem. I cannot see why this valve should be able to fire up the boiler independently of the Controller, whether the valve is sticking or not. It seems that the controller is not actually in control. Can anyone enlighten me on this? Our plumber is not happy with electronics and our electrician is not happy with heating systems.
    MY assumption is that the valve should be able fire up the boiler but only via the controller. If the controller is off then nothing.... if the controller is on then the boiler should start. is this too simple to be correct?

    Thanks for the help (from anyone)

  3. #3

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    Quote Originally Posted by gbcambridge View Post
    We recently had a Honeywell wireless controller and thermostat installed in our boiler system. It has worked well for months. Then we found that the boiler was coming on at night (sometimes) even though the Controller was indicating that the boiler was off!
    This was put down to a sticking valve by the hot water tank... as the water cooled this triggered the boiler. It should then have been heating just the HW but the sticking valve caused it to heat the radiators, which is how we came to notice it.
    Now, here is my problem. I cannot see why this valve should be able to fire up the boiler independently of the Controller, whether the valve is sticking or not. It seems that the controller is not actually in control. Can anyone enlighten me on this? Our plumber is not happy with electronics and our electrician is not happy with heating systems.
    MY assumption is that the valve should be able fire up the boiler but only via the controller. If the controller is off then nothing.... if the controller is on then the boiler should start. is this too simple to be correct?

    Thanks for the help (from anyone)
    Does your heating circuit also have a 2-port valve to isolate it from the hot water?

    The zone valve of your hot water tank has an end-switch that operates when the valve is fully open. The valve is wired in series with your hot water timeclock and cylinder thermostat so the valve opens when the timeclock is on and the stat calls for heat. When fully open the end switch operates and this in turn is wired to the boiler and pump so it runs when the cylinder needs heat. If the valve/end switch are faulty and operating even when the stat or timeclock are off then it needs replacing. This will stop the false call fpr heat and prevent the boiler from running.

    You heating should also have a 2-port zone valve which is operated by the Honeywell boiler relay module and again the end switch should be used to operate the boiler and pump.

    The end switches are used to electrically isolate the feeds from the heating and hot water circuit controls to prevent unwanted back feeds. If you wired direct to the boiler and pump you would probably need interface relays to do the same job as the valve end switches.

    The mains supply to the valve end switches is often taken direct from the heating circuit rather than from the switched live being used to operate the valve therefore if the valve sticks fully open then the boiler and pump will switch on regardless of what the controls are doing.

    If the boiler relay is off then the heating valve should be closed and no hot water should be able to flow around the radiators even if the hot water system is calling for heat.

    I would therefore suggest that both zone valves are checked for correct operation - the heating zone valve should only open when the boiler relay is on and most Honeywell devices have a manual override button you can use while this is tested. The hot water valve should only open when the hot water timeclock is on and the stat is calling for heat. In either case the boiler should only operate when one of the zone valves is fully open.

  4. #4
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    Default Thanks for that answer

    Wow ... I have to confess to being an IT guy and I really find the terminology of the heating world really baffling.
    However, to my muddled mind, this answer seems to give me some direction. The first thing to do is to get the sticking valve replaced and then we will test the system to see how it functions.
    I have trouble answering questions such as "do we have a two-port valve" as I am not sure what it is, unless it deals with directing hot water to the radiators and / or the HW system. I shall do some reading up on this stuff.
    I must say that the guys doing the wiring of these systems seem very gung-ho .. if it was an IT system, we would (should) spend as much time testing it as setting it up... different worlds I guess. The new valve and switch comes on Monday and then we shall see.

    Thanks for that very informative and prompt reply

    George

  5. #5

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    Quote Originally Posted by gbcambridge View Post
    Wow ... I have to confess to being an IT guy and I really find the terminology of the heating world really baffling.
    However, to my muddled mind, this answer seems to give me some direction. The first thing to do is to get the sticking valve replaced and then we will test the system to see how it functions.
    I have trouble answering questions such as "do we have a two-port valve" as I am not sure what it is, unless it deals with directing hot water to the radiators and / or the HW system. I shall do some reading up on this stuff.
    I must say that the guys doing the wiring of these systems seem very gung-ho .. if it was an IT system, we would (should) spend as much time testing it as setting it up... different worlds I guess. The new valve and switch comes on Monday and then we shall see.

    Thanks for that very informative and prompt reply

    George
    If you search for V4043H you should find plenty of links to Honeywell 2-port valves so you can see what they look like. There are many variants from lots of manufacturers but they all stick to the same basic operation and wiring requirements (using either 5 or 6 wires - 3 wires for the switched live, neutral and earth connections to open the valve, the other 2 or 3 are for the end switch).
    Sensible Heat
    SensibleHeat.co.uk

  6. #6
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    Default More on this Heating Problem

    Hi,
    well I did look up the V4043H and it seems to be a simple 2-way motorized valve. SO, since it is only two way, how could I have setting on on the Honeywell controller for independent Hot Water and / or Heating? To my simple mind it looks like the hot water is always running (controlled via a clock on the Controller and a thermostat on the tank) and occasionally the hot water is diverted to run through the radiator system. Is this how it really works? Is this the Honeywell Type C setup?
    Having said that, I stil cannot see how the cylinder thermostat can cause the boiler to fire up when the controller is set to off for heat and hot water. Surely that is a wiring error?

    I have to say that the information I am getting from http://sensibleheat.co.uk is probably the most informative that I have had, including from my local specialists ..... so thanks to all concerned

  7. #7

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    You've almost got it right

    If you use 2-port zone valves like the V4043H then you actually have two valves installed, one on the heating circuit and one on the hot water circuit. These are then independently controlled by the heating and hot water controls. Therefore you can either have heating only, hot water only, or both services running at the same time depending on which valve is open. This is what Honeywell refer to as their S-Plan plumbing design.

    If you only have a single valve fitted then it will be a 3-port valve, such as the Honeywell V4073A. Honeywell refer to this as their Y-Plan design and here the valve has 3 positions, heating only, hot water only and heating + hot water. This has a much more peculiar wiring arrangement though and is much more difficult to test for correct operation.

    I always have to re-read the Y-Plan wiring guide to remind myself exactly how it is meant to work because it is not straight forward and easy to mis-wire!

    For S-Plan systems you simply need a switched live for heating demand and a switched live for hot water demand. For heating this may be direct from a thermostat in series with a time clock or from a dedicated device such as the Honeywell Boiler Controller used by the Hometronic system. Hot water demand is usually from a timeclock in series with the cylinder thermostats.
    Sensible Heat
    SensibleHeat.co.uk

  8. #8
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    Default Yet More on this Heating Problem

    Hi,

    thanks for that very informative answer.
    Having just run round the house I can only fine one V4043H installed ... in the airing cupboard, next to the hot water cylinder. Perhaps there is somewhere else to look but I have not found anything.
    This is why I think it is wired a a C-Plan layout (according to Honeywell RF2 pack 2 instructions). I agree that a 2 times V4043H installation would make more sense, but if it is the C-Plan, then it seems to me that if the valve is closed then only the radiators are heated. If the valve is open then heating goes to the radiators and the HW supply.
    I guess I need to check more around the house on this.... when I find out what is going on I might even write it down!

    Thanks once again

    George

  9. #9
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    Default

    go with infrared for sure! i've made my choice for them a year ago and dont regret it. desides the price is good. i've gone with Thermo imfrared electric heating you can check them out. and ask your questions

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