Horstmann electric heating timers

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mossym

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My current timer for my gas heating is one of the clickety click pust out the tabs versions. I want to replace it with an electric timer, and was looking at the horstmann timers. I ahve 3 zones going from my boiler, upstairs rads, downstairs rads, and hot water, so i'm going to get the 3 channel timer H37Xl. the 3 zones are currently controlled by manual valves, so will need to change those, but no problems there. My question is about the timer itself. it controls 3 channels, for my 3 zones. but when a zone is switched on does it also switch on the boiler, or does the boiler need it's own channel? i guess the boiler is switched on whenever a zone is switced on, but just wanted to make sure
 
Have you done a site search on these? I'm fairly sure a bit of discussion came up about these very timers a few weeks back.
 
thats what pointed me in their direction, but this question wasn't discussed, unless there was another thread i missed,
 
Yeah - I don't think that any previous threads went into this level of detail/specificity on channels etc.

I think you'd need to understand the existing wiring and what controls what before installing a new control/timer. That's the way I approached it when I eventually got around to doing this the other weekend but that was a lot simpler (i.e. effectively a single channel).
 
wiring a single channel one up to control just the boiler makes sense to me. with the horstmann 3 channel, and electric valves on the pipe for each zone, i presume each channel opens and closes the valve as neccesary, as the times are set, i'm just wondering apart from controlling the valve does each also turn on the boiler, or do you need a sperate channel set to come on whenever one of the 3 zone channels is on, or at the same time that it sends a signal to the electric valves does it fire up the boiler automatically
 
If you're fitting 2 port valves to control the heating zones, I think you'll find that most valves have auxiliary contacts to turn on and off the boiler.
These are all connected in parallel with each other, so that when any valve is open the boiler will run. You need to make sure that you are controlling only the boiler, not the pump, which should be controlled by its own thermostat. Presumably the system has a bypass already.
 
ah, thanks for that hoagy. that makes sense. i'll dig out the manual for one of the valves and check it
 
we have this control box on our house and when the time selected comes on the control box, the gas boiler comes on afterwards, i presume it sends a signal to the boiler to turn on. They are brilliant only issue is that you can only have 3 on/off times per zone per day/night.
 
johnnyg said:
we have this control box on our house and when the time selected comes on the control box, the gas boiler comes on afterwards, i presume it sends a signal to the boiler to turn on.
Click to expand...
Are you sure that it doesn't just "send" electricity to the boiler to switch it on - i.e. a timer switch?
 
it looks that way from the wiring diagrams, there seems to be a switched connection through each valve to the live feed of th boiler, which would turn it on. i think my original question has been answered, enough for me to kow i need the 3 channel version, not the 4
 
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