Unvented Heating System - Noise Issue - Gledhill - 6 months on
- Thread starter jklondon
- Start date
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The green PRV I believe is on the incoming mains - it should be set to the same as the unvented to allow any other cold outlets that aren't on the balanced outlet of the vale, to be balanced to the HW output.
The combi set is the right way around if the mains flow is left to right, running under the cylinder then up and back into the inlet.
The supply with the blue lever valve looks like the balanced feed from the bottom of the combi set.
First place would be to balance the EV pressure closer to the dynamic pressure of the mains.
You say there has been work on the mains? Has there been a noticeable changing in flow/pressure?
The combi set is the right way around if the mains flow is left to right, running under the cylinder then up and back into the inlet.
Nope, there shouldn't be any valve on the inlet, downstream of the valve. It would allow one of the UV's safety features (the EV) to be isolated from the cylinder, the lever should be removed from that valve to stop tampering or moved upstream - (to the right?) - of the valve and gauge.
The supply with the blue lever valve looks like the balanced feed from the bottom of the combi set.
First place would be to balance the EV pressure closer to the dynamic pressure of the mains.
You say there has been work on the mains? Has there been a noticeable changing in flow/pressure?
I think you should get a G3 qualified engineer to look this over ASAP.
The red lever valve should not be where it is. The pressure on the unvented side needs setting correctly to the cylinder spec. The expansion vessel pressure should be set to the unvented tanks spec. The incoming mains pressure reduction valve needs to be slightly above the pressure set on the unvented cylinders pressure valve.
The red lever valve should not be where it is. The pressure on the unvented side needs setting correctly to the cylinder spec. The expansion vessel pressure should be set to the unvented tanks spec. The incoming mains pressure reduction valve needs to be slightly above the pressure set on the unvented cylinders pressure valve.
I actually meant right to left ...
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The thing that puzzles me is the conditions that cause this. Now we have pressure gauges from cold mains into the house and upstairs next to the EV. They are fixed levels most of the time and sometimes when we draw HW it causes noise other times it does not. Doesn't matter on the tap either.
On the video the pressure gauge before the EV went down, could this be due to a flow restriction somewhere before that gauge?The thing that puzzles me is the conditions that cause this. Now we have pressure gauges from cold mains into the house and upstairs next to the EV. They are fixed levels most of the time and sometimes when we draw HW it causes noise other times it does not. Doesn't matter on the tap either.
Can you try and make the noise again and press a screwdriver to certain bits and to your ear to hear where the noise is coming from?
Could you (1) shut off the blue handled isolating lever valve at the combination set on the balanced mains and open a hot tap only and see if the noise persists and (2) reopen this valve and just open a cold water tap only close to the balanced cold and see if the noise occurs.The thing that puzzles me is the conditions that cause this. Now we have pressure gauges from cold mains into the house and upstairs next to the EV. They are fixed levels most of the time and sometimes when we draw HW it causes noise other times it does not. Doesn't matter on the tap either.
Did this morning.
When opening hw tap 5 seconds vibration then after closing, 10 seconds later there is long whine. From what I can figure using screwdriver it's coming from around the EV if not itself, Def vibrates.
Yea it hasn't, because it was holding pressure. But needs to be ruled out. Is the type / brand / size ok or should we be looking for something else? Also mentioned above should it be vertical? Thanks again
The 18L is adequate but would suggest going for a 24L EV, the 18L, precharged to 3.0bar will result in a final pressure of 4.1bar after reheating the whole 210L from 15C to say 65C, a 24L will result in a final pressure of 3.8bar, you can go bigger if you wish as you can't oversize a EV, it just results in a lower final pressure.
If its no problem installing it vertically then do so but it really should not be a problem mounting it horizontally IMO.
Edit see pressure recalculations, above.
If its no problem installing it vertically then do so but it really should not be a problem mounting it horizontally IMO.
Edit see pressure recalculations, above.
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Still comes back to the EV and the pressure differentials between the static pressure held in the system when the cylinder is up to temp and the water hasn't been used overnight. With the significant drop to dynamic pressure when the HW is used, that release of pressure from the vessel into the system, I believe, is causing the membrane in the vessel to vibrate, creating the noise.
As was suggested previously, the membrane could be the issue and needs replaced (new EV) but I would still drop the EV pre-charge down a bit closer to the system's dynamic levels to see if the noise changes
When you open the HW outlet do you get a sudden rush of water pressure and then it settles down after the vibration stops? Also, again, you mentioned outside water works, is there a noticeable change in pressure from before, when you have multiple outlets open. What is the pressure reading at the mains PRV when 2 or 3 outlets are open at the same time?
As was suggested previously, the membrane could be the issue and needs replaced (new EV) but I would still drop the EV pre-charge down a bit closer to the system's dynamic levels to see if the noise changes
When you open the HW outlet do you get a sudden rush of water pressure and then it settles down after the vibration stops? Also, again, you mentioned outside water works, is there a noticeable change in pressure from before, when you have multiple outlets open. What is the pressure reading at the mains PRV when 2 or 3 outlets are open at the same time?
It would be useful to have the actual mains pressure even though the requlated pressure should reflect this if its 2bar or less, the pressure at the combination set PRV inlet (which is measured) should be somewhat less depending on the flowrate, pipe length and pipe size, the flowrate should also be measured.
Thanks so far arranging to have EV replaced.
Question - this started around the time we had main bathroom redone and new ensuite in my kids room. However the issue occurs with any hw tap in the house. Could it still be related to a tap / valve from the works somehow?
Question - this started around the time we had main bathroom redone and new ensuite in my kids room. However the issue occurs with any hw tap in the house. Could it still be related to a tap / valve from the works somehow?
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