economy 7 water heating

Hi, Quick question guys, Economy 7: Went to a customers property today timer has never worked since the water heater was changed. water will not heat during the night on the timer and only works when the boost is pushed during the day. . so had a quick look at consumer one supply to the timer off the 24hr ccu, went into the loft found two fused spurs one for the boost which was connected to the thermostat at the top of the water heater and one for the timer which became live when i set the timer to work but this had no out going flex. Am i correct in thinking they have fitted the wrong water heater as there should be an element at the bottom for the night time supply.

Cheers

There are two ways of doing it.

It sounds like the old cylinder had two heater elements. The bottom one is energised over night to give a full tank overnight at the cheap rate. The top one is energised by the timer as and when needed for a top up.

It sounds like the new tank only has one heater element.

You CAN use most boost controllers but you need a bit of rewiring. Assuming it's a normal Horstman boost controller, you should have one permanent feed and one off peak feed into the controller, and you can rewire it to use the same heater for overnight, or daytime boost.

The wiring diagram should be inside the boost controller.

If it's not a Horstman, post a picture and model number and between us we will see what we can dig up.

Cheers Prodave.

yes the timer is an old maxistore horstmann.

There is only one permanent feed from the 24hr consumer there is no feed from the off peak consumer. from the timer a flex comes from the boost setting to a fused spur in the loft. there is also a flex for the timer control which is set to 12.00 to 7.00 this also goes to a fused spur in the loft

Cheers Prodave. yes the timer is an old maxistore horstmann.

There is only one permanent feed from the 24hr consumer there is no feed from the off peak consumer. from the timer a flex comes from the boost setting to a fused spur in the loft. there is also a flex for the timer control which is set to 12.00 to 7.00 this also goes to a fused spur in the loft

Click to expand...

Ah I see. The off peak feed goes straight to the tank and the boost timer was only used for the top up heater.

In which case you need to do more work than I thought. If you route the off peak feed to the Horstman, then it can be reconfigured to operate just the one heater, giving it a full charge overnight, and a timer top up whenever you need it.

Cheers dave

i've just been thinking, in the back of time switch is the following: terminal 1 live in terminal 2 neutral in terminal 3 neutrals out terminal 4 boost out terminal 5 off peak out.

would i be able to remove off peak cable from terminal 5 & 3. and put a link in between 4 & 5 terminal.

would this work, as this cable is utilising the cable already attached to the immersion.

off to work now cheers.

I'm not following what you mean, and can't recall which terminal does what. All I remember is there is a wiring diagram inside them.

What you NEED is both a permanent and an off peak supply.

The way it works, is when the switch is in "timed" position, the off peak supply is connected to the heater.

As soon as you rotate the boost dial, a double pole changeover switch (built into the dial) changes over to connect the heater to the permanent supply and feeds the heater like that until the timer expires, whereupon the changeover contact switches back, and the heater is ready to be powered by the next over night period of the off peak feed.

So it NEEDS two feeds two the controller, and one cable from the controller to the heater element.

Your task is how to achieve that using the cables you have without having to pull any more cables through. But it sounds to me as though you only have two cables connected to the horstman, in which case finding a route to connect a third is unavoidable.

I think you will find that Horstman Timer only has one input from the 24 hour supply and the option for two outputs, one to botton element timed and the other to top element for Boost.

I think you will find that Horstman Timer only has one input from the 24 hour supply and the option for two outputs, one to botton element timed and the other to top element for Boost.

Click to expand...

Well definitely in one of our rental properties we have a tank with a single heater, fed from a Horstman with two supplies, so they CAN do 1 heater from two supplies.

Perhaps my confusion is this is not a selectable configuration, and they have to be ordered like that?

See below

http://www.horstmann.co.uk/downloads/ElectronicDocuments/Electric-Water-Heating/Electronic7_data_print.pdf

Well done Sparkytim

What you have highlighted is the current electronic version will work with one feed, and one heater connection.

I was probably in a time warp. MOST of the one's I see in use are the older ones, with a mechanical clockwork timer dial, and they do need 2 feeds.

So the answer to the OP's dilemma is that's it's probably a lot easier and cheaper to buy a new electronic timer, rather than mess about trying to pull another cable through the get the existing old type timer working properly with a single heater.

Hi i have found an installation manual and you can run from one feed can anyone see anything wrong with putting a link as i have suggested on a previous post. Cheers much appreciated

Yes you can link the timer and boost terminals to feed the ONE element

See link to Horstman site above

You can link 4 and 5 together which will allow the timer to work only it won't be at the off peak rate

With Economy 7 and 10 etc the WHOLE HOUSE is at the off peak rate during the off peak period, ALL circuits will benefit hence why folk use timers to do the washing etc at night.

As above, the only thing that happens at the meter is the 5th tail is switched on and the rate for both outputs on the meter changes to the lower one. Horstman to loads of controllers that can be configured differently depending on whether you have an o/p and peak supply or both, and two or one immersions. I typically fit a bx2000, but that needs the two supply's and provides one or two outputs, and has a one or two hour boost timer.