Really loud noise when secondary...

[chris watkins]

Was there anything to stop the secondary return going back to the cylinder ?
Just thinking it is strange to have a blending (tempering) valve on the outlet of an un-vented as they should be controlled by the stats. If it has been fitted to actually reduce the temperature of the HW flow to the fittings then the return could have been taken back into the cold supply to the valve, otherwise the return water to the cylinder would cool its stored temperature causing it to reheated. This HW would then be drawn out of the flow only to be blended back down by the cold, if that make sense. Very poor design, my guess is the return goes through the valve no (or very little) back to the cylinder.

 

[mutley racers]

Was there anything to stop the secondary return going back to the cylinder ?
Just thinking it is strange to have a blending (tempering) valve on the outlet of an un-vented as they should be controlled by the stats. If it has been fitted to actually reduce the temperature of the HW flow to the fittings then the return could have been taken back into the cold supply to the valve, otherwise the return water to the cylinder would cool its stored temperature causing it to reheated. This HW would then be drawn out of the flow only to be blended back down by the cold, if that make sense. Very poor design, my guess is the return goes through the valve no (or very little) back to the cylinder.

Hi Chris, below is a sketch up of the old set up before I removed the valve.

Not the best sketch but hopefully you get the just. I believe the return was basically feeding the valve.

 

[mutley racers]

Do all secondary return connections into the cold feed need a swept tee?

 

[ShaunCorbs]

No

 

[mutley racers]

So this is the original layout

 

[mutley racers]

This is how it is now. But I still for the life of me cannot think why this alteration would make it take longer to get to the kitchen. Surely the water would arrive at the tap at the same time as the flow and pressure are the sMe and the water is stored at 60

 

[ShaunCorbs]

Problem is your pulling blended water round so it's cooler

Try putting a nrv just above the cold tee

 

[ShaunCorbs]

This is how it is now. But I still for the life of me cannot think why this alteration would make it take longer to get to the kitchen. Surely the water would arrive at the tap at the same time as the flow and pressure are the sMe and the water is stored at 60

View attachment 36283

So you've removed the tmv3 and capped the cold ?

 

[mutley racers]

So you've removed the tmv3 and capped the cold ?

Yep

 

[ShaunCorbs]

In theory it should work is the pipework warm going to the pump ?

 

[mutley racers]

Yes it was all getting warm.

With regards to the control of the secondary circuit, what is the best? Just timed for high peak demands?

 

[ShaunCorbs]

Yea normally set for hours that the place is in use with a boost / overrun

 

[mutley racers]

Yea normally set for hours that the place is in use with a boost / overrun

Thought so. This is what it has got.

 

[ShaunCorbs]

Very strange

Only thing I can suggest is remove pump and open the return leg to the cylinder does that get hot hot

If yes put a nrv where I said eg after the tee where the pump is on the cold pipe to the cylinder

 

[mutley racers]

Very strange

Only thing I can suggest is remove pump and open the return leg to the cylinder does that get hot hot

If yes put a nrv where I said eg after the tee where the pump is on the cold pipe to the cylinder

When you say remove pump and open return leg, do you mean open the pump valve and let water out and see if it is hot?