I have an L & G RWB2 and I'm happy with it. However, I would like to know why the CH pump comes on about 15 minutes before the gas ignites. I guess there's a simple answer but I'm not sure why cold water needs to be pumped around for 15 minutes. 
Landis & Gyr - RWB2 Twin Channel Heating Program
- Thread starter eddieriff
- Start date
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Could be an issue with the programmer switch points (HW & CH) or it might be a sticking gas valve on the boiler??
Personally I would not worry about it until it no longer works -the fault will be much easier to diagnose once it has stopped working!!
Personally I would not worry about it until it no longer works -the fault will be much easier to diagnose once it has stopped working!!
Could be an issue with the programmer switch points (HW & CH) or it might be a sticking gas valve on the boiler??
Personally I would not worry about it until it no longer works -the fault will be much easier to diagnose once it has stopped working!!
Thanks for that BM2. I'm not worried at all, just curious. Thing is, it's the second one I'm on to. There was nothing wrong with the first apart from a non working slider but theses programmers are the only ones that's been used and the original did the same from the installation of the system.
Interesting you should highlight this problem.
I have the same issue. CH comes on and pumps cool water round radiators for 3mins then HW comes on.
Of course it's to do with the cam that switches them both on, well not so much the actual cam because there's only one, but the two parts it engages with. Could be worn on the HW part so HW comes on 3mins late.
Even when brand new there is a few seconds difference
So options appear to be replace programmer with a RWB9 digital.
Or swap the HW ON wire with the CH wire making the CH come on 3mins late.
The HW switch would become the CH switch and vis versa
I have the same issue. CH comes on and pumps cool water round radiators for 3mins then HW comes on.
Of course it's to do with the cam that switches them both on, well not so much the actual cam because there's only one, but the two parts it engages with. Could be worn on the HW part so HW comes on 3mins late.
Even when brand new there is a few seconds difference
So options appear to be replace programmer with a RWB9 digital.
Or swap the HW ON wire with the CH wire making the CH come on 3mins late.
The HW switch would become the CH switch and vis versa
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Hm, waiting until you heating stops working in the middle of winter wouldn't be my preferred option....
Does it always turn on the boiler with a 15 mins delay.
Then I would check with a multimeter that things that were switching - programmer, output from the zone valve microswitch etc. were turning on correctly. starting with the programmer
If you don't understand how the system works a few piccies, or a diagram, of the system/components and the wiring will help people to help you.
Does it always turn on the boiler with a 15 mins delay.
Then I would check with a multimeter that things that were switching - programmer, output from the zone valve microswitch etc. were turning on correctly. starting with the programmer
If you don't understand how the system works a few piccies, or a diagram, of the system/components and the wiring will help people to help you.
There is another way of eliminating this problem with this type of programmer.
Basically you make the timer with its cams redundant. How?
Well by putting both HW and CH switches to constant.
Then introduce another timer to supply power to the programmer and a switch.
So existing power goes to wall socket (instead of programmer)
In the wall socket a 'timer' is plugged in (plug in timers are only around £6 and can be digital).
In the outlet of the timer is a 3pin 'switched' plug with cable going to the programmer'.
With plug switched off, no power to programmer,so no HW or CH
With plug switched on its controlled by the new plug in timer.
So both HW and CH come on at the same time. (it can't do one without the other).
If CH not required, turn it from constant to off on the programmer.
If programming is not required, then remove 'timer' and just use switch to turn on or off.
Only problem with this is, a socket,timer, plug and cable if on view may be unsightly whereas if in airing cupboard could be acceptable.
Basically you make the timer with its cams redundant. How?
Well by putting both HW and CH switches to constant.
Then introduce another timer to supply power to the programmer and a switch.
So existing power goes to wall socket (instead of programmer)
In the wall socket a 'timer' is plugged in (plug in timers are only around £6 and can be digital).
In the outlet of the timer is a 3pin 'switched' plug with cable going to the programmer'.
With plug switched off, no power to programmer,so no HW or CH
With plug switched on its controlled by the new plug in timer.
So both HW and CH come on at the same time. (it can't do one without the other).
If CH not required, turn it from constant to off on the programmer.
If programming is not required, then remove 'timer' and just use switch to turn on or off.
Only problem with this is, a socket,timer, plug and cable if on view may be unsightly whereas if in airing cupboard could be acceptable.
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