Baxi Bernuda

[ib333]

Hi,
I have just moved into a house and the CH system wont work without the HW being switched on. It dosnt matter what position the room thermostat is set at. The controller is a Honeywell ST699 and the boiler is a Baxi Bermuda inset 2 50/4E back boiler.
The controller is set to twice a day CH and HW the boiler fires up no problems every thing gets warm then if I was to put it on manual/constant the CH will not work unless the HW is switched to constant as well.
Thanks in advance.

 

[Agile]

That's usually the way the system is designed for those old boilers.

Best get it serviced too.

Tony

 

[ianmcd]

you have a Gravity hot water /pumped central heating system so you can have HW on its own or HW and CH at the same time but not CH on its own and as Tony correctly advises it is extremely important that these are serviced every year, you have a great very reliable system although old it will not let you down but servicing is very important on these

 

[ib333]

Thanks for you reply according to the paperwork it has been serviced every year in April.
Just to clarify then if I want the CH on I have to have the HW on for it to work, it seems as when the hot water tank gets to the required temp the CH cuts out and no matter how high you turn the room thermostat it wont come back on.
Also if the HW is turned on and the CH is turned off the rads get hot as if the CH is on as well, is this how it should be


Thanks again.

 

[FiremanT]

Thanks for you reply according to the paperwork it has been serviced every year in April.
Just to clarify then if I want the CH on I have to have the HW on for it to work, it seems as when the hot water tank gets to the required temp the CH cuts out and no matter how high you turn the room thermostat it wont come back on.
Also if the HW is turned on and the CH is turned off the rads get hot as if the CH is on as well, is this how it should be


Thanks again.

No.

I promise to get back here when sober. Seriously. But first, is the pump in the airing cupboard, or by the boiler?

Are there any motorised valves, normally on the airing cupboard?

 

[Agile]

None of us have seen your system!

We can only guess taking into account how many of these were installed.

A few photos of the relevant bits might help us!

Tony

 

[Coaster]

I've got this system.
yes the hw has to be on for the CH to work.

I have the ch pump in a cupboard next to the chimney breast. as for the symptoms.. No it shouldn't be doing that.

To me it sounds like the control unit with the switches to select hw and ch?
On ours the ch switch has 3 positions.. down for on, middle off, up for timer. you may think its off but may be on timer by mistake as the switch positions are close, and if the clock is on for a particular time your ch will kick in.

 

[Agile]

I have always thought the ST669 had nicely defined detents on the sliders!

Particularly when placed in the off position I don't see how anyone could ever be confused!

But regardless of the timer, the fact that on 95% of those installations its gravity hot water makes it very unlikely that it is really a system giving full independent control.

Tony

 

[ib333]

Hi,
Thanks for the reply, the pump is located in the kitchen cupboard to the side of the boiler/chimney there are from what I can feel three wires coming out of the timer one is the feed in one goes to the pump and the other goes into the wall towards the back of the boiler. There are no valves in the airing cupboard that I can see just the HW tank and the switch for the heating element and pipes going to the loft tank and down to the boiler etc.
Thanks again.

 

[ib333]

View media item 68674 View media item 68675
They are not the best but hope they help.

Thanks.