Central Heating/Hot water Programmer Timer help

Up to yesterday I had a Myson Microtimer central heating / hot water timer. However, the relay went pair-shaped and would not stop clicking meaning we had no hot water or heating.

Anyway I went with my electrician brother to B & Q and purchased a Sunvic Select 207 XL programmer.

My brother made note of all the wires in the connection plate and then wired up the new timer accordingly. However, the system wont work properly.

If you advance the hot water to on, although the light comes on the timer, the pump does not come on and the boiler does not fire up.

If you advance the central heating the pump starts but the boiler does not kick up.

If you advance the hot water and the central heating, the pump starts and the hot water heats up, but the radiators dont warm up. However, if you over ride the valve in-line with the water tank to manual you can get the radiators to come on. Having said that the living thermostat does not seem to have any effect on the central heating / boiler.

We are sure there's a wire or 2 amiss here somewhere. The new timer has 6 terminals with two being live and neutral leaving 2 terminals for hot water and 2 for central heating. However, there's quite a few wires which my brother has sorted into a connection strip to then connect to the plate on the timer connector bracket.

Perhaps we should go back to square one but we would need to look at each unit i.e. valve, pump, tank thermostat etc and need to know the wiring colour coding used and then know where it goes.

I can see blue, yellow, white, brown, red and also orange wires.

Help would be greatly appreciated.

Thank you in anticipation.

Anyway I went with my electrician brother to B & Q and purchased a Sunvic Select 207 XL programmer.

My brother made note of all the wires in the connection plate and then wired up the new timer accordingly. However, the system wont work properly.

Oh dear we would need more info about controls you have etc, if a electrician can't work it out.

Apollo boiler in kitchen

C/heating thermostat in living room

Copper tank, valve, pump, timer (with fused spur) in an upstairs cupboard adjacent to a bedroom.

The tank has a thermostat located 1/3 of the way up the tank.

The valve has pipes which run to the copper tank and pump.

Thermostat, valve and pump each have flex cable going to timer.

The timer also has feeds from the boiler.

Here's some info on the new timer:
http://64.233.183.104/search?q=cach...sunvic+select+207+xl&hl=en&ct=clnk&cd=1&gl=uk

Some of the wires were paired i.e. orange and red and brown
white and blue
grey and blue

My brother has paired the same wires which were paired up in the myson microtimer connection plate - then connected the ones which were in the terminals connected to the previous timer to the new timer connection plate.

I dont want to mess with the timer right now as my young daughter is asleep in the room next to where the timer etc are located.

When you say valve do you mean motorised valve?.

If so is it 3 port ie 3 pipes, or 2 port ie 2 pipes, if 2 port do you have 2 of them?
what make are they?.

The valve (Boss Therm BMPV2 222) pipe set up looks like a T

With a pipe on the right of the valve going into the copper tank

A pipe comes out from the left of the valve and goes out at a right angle and drops straight down into the floor space - There's a few pipes coming off the main pipe - one goes into the bottom of the copper tank

The bottom pipe comes off the valve goes left on a right angle and up to the pump which has a outlet valve in-line going up into the loft

He He since when has a sparky been able to do electrics on a heating system on there own?
Not met one yet.

lagunaglen said:

He He since when has a sparky been able to do electrics on a heating system on there own?
Not met one yet.

Click to expand...

You got anything helpful to post please?

Don't know that make of m/valve but sounds like a 3 port valve.

If it was a Honeywell 3 port valve and with the rest of the controls you say you have you would be using HW on HW off and CH on terminals of your programmer. the Honewell valve is a spring return valve with a lever on the side which you can push over against the spring and it will return on it's own does your valve do that?.

The honeywell valve has a orange wire which is used to feed pump and boiler usually.

Cylinder stats usually have three connections marked C 1 & 2, a change over switch.
Terminal 2 is used to feed m/valve when hot water is satisfied.

Room stats have switch connections also but you don't usually use it as a change over just as make or break.

Is this any help.

The valve has a lever on the side with 'auto' and 'manual' settings. I can get the c/heating to work when I move the lever over to 'manual' and when I switch the c/h off, the lever returns to 'auto'.

It does help - thanks Waterworks

I am really surprised that wire colour is not standard on these things, so whoever comes along can easily work out what goes where.

Looks like my brother would have been better off looking at each unit and working out what the wires were for - then he'd have sorted this.

Looking at the terminal block, 1 and 2 are live & neutral (or vide-versa) and the next 4 are 2 for c/h and 2 for h/w.

Just need to work out where the rest of the wires need to interconnect.

Might be best to remove all the wires and start from scratch

Have a look at page 13 a post called mid position valve wiring, there is a diagram of a honewell y plan system it may help you.

The terminal equivalents are as follows:

Myson Terminal 7 = Sunvic Terminal 1 = HW OFF
Myson Terminal 6 = Sunvic Terminal 3 = HW ON
Myson Terminal 3 = Sunvic Terminal 4 = CH ON

(The CH OFF terminal is not used)

There are also L, N and earth terminals on both timers.

Provided you have not written it down wrongly you should have no problem.

But just in case, here is the wiring diagram:

Thank you for your all help

The Pump wiring will be brown = live / blue = Neutral / G & Y = earth
but what colour coding, if any, will the room stat and tank stat be please?

richardwalton said:

what colour coding, if any, will the room stat and tank stat be please?

Click to expand...

There is no standard colour coding for these components. You just have to take the covers off and check which color has been connected to which terminal. You need to check both ends. It's a tedious job, but it's the only way.

One word of warning: you may find that the green/yellow (or bare) wire has been used as a volts carrying wire instead of as an earth. It's the sign of a lazy electrician who can't be bothered to use the correct cable!

If you can't work it out, post as much info as you can about the wiring and we will sort it out for you. Photos are often helpful.

Thanks