wireless room thermostat

[daverichardson]

Just checked wiring and all looks ok so I swapped the black wire from the bottom terminal in x5 in the boiler and put it in the third one up. i left the second black wire alone in terminal 2 and the boiler now works on demand from the transmitter
It also works on demand from the hot water tap
So it looks like job done providing you agree with using terminals 2 and 3 in X5 for the black wires
(I also altered the earth as per diag)
Please let me know if this is ok nd i will progress the programming
dave

 

[D_Hailsham]

I did say

Black 1 - A - X5/T3
Black 2 - B - X5/T2

Happy Programming!

 

[daverichardson]

oops my mistake
and thanks again
Now for phase 2 can you help - it is not electrical!
My boiler is a Worcester Bosch 280RSF (discontinued in the 1990s)
There is a feeder tank in the loft (only a small one) and I am not sure what it does
The boiler when off shows no pressure on the pressure guage (all green with no red segments, but a blood line adjustable needle set at 1 bar)
When the boiler is in use the pressure gets to about 0.8bar
I have seen on the Worcester website that it needs pressurising, is this correct with the atmospheric loft tank?
If so how do I do it?
I cannot find an external loop for pressurising and I cannot find a key or housing to allow this as described on the website
ps programming gone well

 

[ChrisBee]

It looks and sounds like a combi which doesnt need a header tank, suspect the header tank is a left over from another boiler ??

There should be a fill loop somewhere, it might have been disconnected as generally they can be, I'm surprised its working and hasnt locked out due to low pressure

Although on page 19 of the manual it does show it can be open vent

http://www.worcester-bosch.co.uk/ca...ctions-for-280-rsf--discontinued-feb-1997.pdf

Chris

 

[daverichardson]

We had the boiler installed in the late 90,s and I remember the chaps putting the new tank in the loft
Thanks for the link to the handbook
what is an open vent?
The system has ran like this ever since the installation, so I am still perplexed.
dave

 

[D_Hailsham]

Although on page 19 of the manual it does show it can be open vent

That's what I was about to say.

DaveR

You need to check if the small tank in the loft is actually connected to the heating system. If it is, you can ignore the pressure gauge on the boiler. The movable hand can be set to zero.

If you have a sealed system ,there should be an expansion vessel, looks like a metal football connected to the system. If you have one, the loft tank is redundant (no water in it). The movable needle shows what the pressure should be when the system is cold. You top it up via the filling loop.

 

[daverichardson]

Hi
I am sure the tank in the loft is connected.
As I say it was part of the original installation in the 90s and nothing has changed and the system has worked like this forever.
I will check tomorrow and let you know.
But it seems all is well?
There does not appear to be a pressure vessel as you describe, but there is a cylinder with rounded ends painted red,near the exchanger at the front of the boiler. It is quite large 12 iin long 7 in dia and zilmet written on it. I cannot make much more out but will try again tomorrow
I don't know what that is!

 

[daverichardson]

Hi
Note the title change!
The wireless thermostat is working fine.
Been in the loft today there is a small green plastic header tank with a cold water supply about 15mm to a ball cock arrangement.
there is an overflow to outside gutter
there is also a larger pipe about 22mm which I think comes out of the bottom of the header tank and the other end goes to the boilertop near the flue. I cannot see where this is connected to in the boiler. It has been treated with inhibitor - 1/2 bottle still left
There are the usual pipes to and from the boiler gas, dhw out, ch flow,ch return from l to right
The boiler operates fine at about 0.3 bar for tap water adn about 0.6 bar central heating
So my question is
Is this a vented system that is not pressurised?
I guess the boiler came as a package with pressure tank and valve but for some reason a vented system was adopted
Is this reasonable?

Just in the process of balancing rads and familiarisation with programming
thanks

 

[mysteryman]

Fit a boiler with built-in weather compensation and timing, and all of this, plus the best fuel economy, is done for you.

 

[D_Hailsham]

Note the title change!

Doesn't work on the original title! Don't know why you can change it on subsequent posts

Been in the loft today there is a small green plastic header tank with a cold water supply about 15mm to a ball cock arrangement.
there is an overflow to outside gutter
there is also a larger pipe about 22mm which I think comes out of the bottom of the header tank and the other end goes to the boiler top near the flue. I cannot see where this is connected to in the boiler.

Does the pipe go into the boiler on the top left side? If so the tank in the loft is acting as the top up for a sealed system. Check if there are any valves in the pipe from tank to boiler. You can see this on page 9, Fig 6 of the manual (link given earlier). This show a non return valve, but the installer may have put in another type.

The only problem with this arrangement is that the pressure depends on the height of the tank above the boiler, so you do not get the full mains pressure. The system pressure will then never rise above about 0.5 bar when cold.

 

[daverichardson]

Hi
Yes the pipe does go into the boiler top on lhs
I did not notice any valves including NRV
So it looks like you are correct.
I am ok about the system pressure it has worked ok all these years with no cut outs etc
Is this a problem?
Should i look for a nrv or similar?
If so it will need to be tomorrow
thanks for all your help
d

 

[daverichardson]

Well guys the system is up and running and I am fine tunning the programmer and radiator settings to suit our requiremenmts.
I checked for the nrv from the header tank and all is well.
So I believe my sytem to be a vented type
May i take this opportunity to thank you for the assistance given
I am now looking forward to lower gas bills!!