CH + HW

[Viren]

Hi,

I am new to this forum, so forgive me if I havent followed the rules of the forum.

I have a heating system that seems to get confused (it could be me that is confused!) when both the HW and the CH are on, so much so that neither work. The boiler and everything else seems to be working normally.

On further investigation, the flow to the HW and CH appears to stop just before reaching the open MVs for the HW and CH in the loft (ie flow pipe hot on one side and cold on the other.

The Heating system is fine as long as only one is on at any given time.

Any suggestions?

BR
Viren

 

[Agile]

It might be a lack of water in the system if its open vented.

Bleed some water from a rad and see if the water level in the F&E tanks goes down.

If sealed whats the pressure shown?

Tony

 

[Viren]

It might be a lack of water in the system if its open vented.

Bleed some water from a rad and see if the water level in the F&E tanks goes down.

If sealed whats the pressure shown?

Tony

It is a sealed system (no leaks!) pressure is at a steady 1.5 bars.

ps Just checked it again with CH on the system is fine, and as I open the MV manually for the HW, both the pipes for the CH and HW go to luke warm/cool, and the flow pipe is still v hot! It is as if there is flow the opposite way?!?! Could that be possible?

BR
Viren

 

[Agile]

Is this a fault that has developed?

When did it last work poperly?

Is there a bleed point at the highest part of the system?

Is the pump working?

Are any rads cold at the top but warm lower down?

Tony

 

[Viren]

Is this a fault that has developed?

When did it last work poperly?

Is there a bleed point at the highest part of the system?

Is the pump working?

Are any rads cold at the top but warm lower down?

Tony

We have recently (12 mons ago) put in a new Keston boiler. The plummer could not figure it out either, but is convinced it has nothing to do with the boiler, as the boiler is installed in the basement and the MVs and pipe work concerned is in the loft! I am sure prior to that the system was fine (only guessing though!).

There are bleed points at the highest part of the sytem (all working fine), and the pump is integral part of the boiler (in the basement).

There is a 2nd pump in the loft (just after the MV) that can be turned on and off manually to speed up the heating in the main part of the house. The rads are fine too when the CH is working properly.

BR
Viren

 

[Agile]

You have not said if this has developed recently or was always like that since the boiler was fitted.

What effect does turning this second pump on or off have on the problem?

Fitting a second pump is NOT normally required and they can cause considerable problems as boilers are not designed to work with any other pump in the circuit.

Tony

 

[Agile]

You have not said if this has developed recently or was always like that since the boiler was fitted.

What effect does turning this second pump on or off have on the problem?

Fitting a second pump is NOT normally required and they can cause considerable problems as boilers are not designed to work with any other pump in the circuit.

Tony

 

[Viren]

You have not said if this has developed recently or was always like that since the boiler was fitted.

What effect does turning this second pump on or off have on the problem?

Fitting a second pump is NOT normally required and they can cause considerable problems as boilers are not designed to work with any other pump in the circuit.

Tony

Not sure if it has developed recently, I suspect it has always been like this, and we have not noticed due to the on times of the CH + HW not coinciding.

There is no effect of turning the 2nd pump on/off.

BR
Viren

 

[Agile]

If it has always been like that then I dont see any other way that having a competent engineer to come and check exactly how its piped and wired.

The mere fact someone has added a second pump makes me think that its likely to be a questionable installation.

Tony