2 bypass valves??

[mhomami]

Hi all,

Can anyone tell me what these two manual valves are and what they should be set at?

So far as I can tell, the lowest one (closest to tank) is the manual bypass and should be set to partially open but the other one has me stumped. What is it and should it be open or closed?

Thanks in advance.

 

[ShaunCorbs]

the highest on is your bypass the lowest is to stop coil vibration (water going round the coil too fast)

the highest one nearly closed, but when the system is hot no water should be flowing through it

tbh best bet is to replace it with a auto bypass

lowest one three quarters to half shut

 

[mhomami]

Thanks for the quick response. I'll have a play with the valves tonight to see if it fixes my problem.

 

[Chalked]

Hi
The smaller one is a bypass and should be open enough to allow the pump overrun on the boiler to work and dissipate heat.
The bottom, larger one, is for controlling the flow of water through the cylinder coil. As your on an "s" plan ( two motorised valves) I would leave or fully open.

 

[mhomami]

Morning all,

I did as suggested. Bypass valve mostly closed, ensured some flow while tank was cold.Flow valve was half closed. This morning we didn't have any hot water so I've opened up the flow valve all the way to see if this fixes the issue.

At the moment I think that the pump may need replacing. We've not had any heat in the downstairs radiators and the pump is a little noisy. However, I've had mixed results when closing off all the rads upstairs which has resulted in some heat coming downstairs. System has been drained so sludge is not a problem.

My question as follows: If pump is on its way out and we have hot water/heat upstairs anyway , why would mostly closing the manual bypass cause a loss of hot water in the tank?

 

[Last Plumber]

It depends.

It's possible in some cases for the upstairs heating to work by gravity when the pump fails.

I can't see pics well enough. Not your fault it's the forum!

Which boiler do you have ?

 

[mhomami]

It's a Potterton Profile 50e. Old thing but appears to be working and has yet to set off the carbon monoxide detector.

I have some picturess posted on imgur but I don't think the forum will let me post them. I have pm'ed them to you. Would appreciate if you could post the same for any future troubleshooters to have for fault finding purposes.

 

[mhomami]

Just wanted to let you guys know that this appears to have resolved my heating problem. Manual bypass is set to mostly closed and flow valve is full open. Hot water works and I have some heat downstairs.

Next step is to balance and install auto bypass.

Thank you all for your kind assistance.