Really loud noise when secondary...

[mutley racers]

Pump is running through Megaflow. Turn off the outlets and it is fine.

Find this on top of the cylinder, was this normal to put on top of cylinder? So the secondary return goes into the cold feed which taps into the top of this...

 

[ShaunCorbs]

Yes the tmv3 is to reduce the temp but normally fitted at tap ends as temp can drop a bit

As for the pump should be hot out to cold inlet

Or like any other src hot to cylinder port

 

[mutley racers]

Turns out the noise was the check valve passing

 

[mutley racers]

Got an email today saying that now I have replaced the SR pump, check valve and mixing valve from top of cylinder it is taking 3 minutes for hot water to get to the kitchen tap. Hmm

 

[ShaunCorbs]

Is the pump on ?

 

[mutley racers]

Is the pump on ?

Not been back to look but she tells me the pump is on and I know they do know how to turn it on

 

[ShaunCorbs]

Pumping in the right direction? Back to the cylinder

 

[mutley racers]

Pumping in the right direction? Back to the cylinder

I definitely made sure of this when I installed it. It was fine until I removed the tmv 3 and replaced the check valve which also is the correct way.

 

[chris watkins]

Air locked return most likely so no circulation.
Did you pull it through to clear the air?

 

[mutley racers]

Air locked return most likely so no circulation.
Did you pull it through to clear the air?

Pull it through? Not cleared up on that terminology. All I did was replace the pump.

Cheers Chris. Good to see the old boys still on the forum

 

[ShaunCorbs]

Pull it through? Not cleared up on that terminology. All I did was replace the pump.

Cheers Chris. Good to see the old boys still on the forum

Didn't change the pump valves ?

 

[mutley racers]

Nope

 

[ShaunCorbs]

Soshould be still full need to check the pipe is warm if it isn't could be an air lock as chris says

 

[chris watkins]

Not so much of the old, young racers me lad!!
Where was the cold for the mixing valve drawn from, the cold feed to the cylinder?

 

[mutley racers]

Not so much of the old, young racers me lad!!
Where was the cold for the mixing valve drawn from, the cold feed to the cylinder?

Ok, less of the old ye shall have.

Yep, the cold feed had combi supply, then the cold feed to cylinder and then into the mixing valve on top of the cylinder

 

[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?

 

[ShaunCorbs]

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?

Yes checking there's no restriction/ blending valve passing back would be the same temp as the water going out of the cylinder after the leg is clear of any cold / lower temp water etc

 

[mutley racers]

Ah ha, tha is Shaun. Will give it a try. Thank for your help as always

 

[mutley racers]

All done. Guess what it was

 

[ShaunCorbs]

Valve shut ?

 

[mutley racers]

Valve shut ?

BINGO!!!!

This is what 3 KIDS under the age of 4 are doing to me. Been called back to like 5 jobs since having a 3rd for not opening valves. Keep leaving my tool bag on people's door steps and driving off only to arrive at another job with no tools. It is getting so bad I am thinking of getting a back up set!