unvented cylinder pressure vessel

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What would be the outcome of a loss of pressure in a pressure vessel on an unvented cylinder.

When taking a shower if a hot water tap is opened the hot water flow in the shower turns to a trickle.

Cold water mains is 1.5 bar
 
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What would be the outcome of a loss of pressure in a pressure vessel on an unvented cylinder.

When taking a shower if a hot water tap is opened the hot water flow in the shower turns to a trickle.

Cold water mains is 1.5 bar

Sounds like your cold mains is inadequate. The installer is incompetent. At the kitchen tap, time the filling of a bucket ion litre per minute.

Ideally, you need a full-bore cold maintap and a dedicated 22mm cold feed to the cylinder, irrespective of pressure and flow.
 
What would be the outcome of a loss of pressure in a pressure vessel on an unvented cylinder.

When taking a shower if a hot water tap is opened the hot water flow in the shower turns to a trickle.

Cold water mains is 1.5 bar

Sounds like your cold mains is inadequate. The installer is incompetent. At the kitchen tap, time the filling of a bucket ion litre per minute.

Ideally, you need a full-bore cold maintap and a dedicated 22mm cold feed to the cylinder, irrespective of pressure and flow.

Many thanks BigBurner. I am unable to test flow rate as I am not at home till later this afternoon ie 3-45 pm.

I presume you are also confirming that problem is not related to the pressure vessel?
 
What would be the outcome of a loss of pressure in a pressure vessel on an unvented cylinder.

When taking a shower if a hot water tap is opened the hot water flow in the shower turns to a trickle.

Cold water mains is 1.5 bar

Sounds like your cold mains is inadequate. The installer is incompetent. At the kitchen tap, time the filling of a bucket ion litre per minute.

Ideally, you need a full-bore cold maintap and a dedicated 22mm cold feed to the cylinder, irrespective of pressure and flow.

Many thanks BigBurner. I am unable to test flow rate as I am not at home till later this afternoon ie 3-45 pm.

I presume you are also confirming that problem is not related to the pressure vessel?

Yep. If you did have a problem you would most probably see a weep of water through the tundish.
 
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Time to fill bucket at kichen tap is 8.5 litres in 1 minute

Or, to put it another way, cr*p. Serioulsy, I could **** faster than that. There's very little you can do to cure this really I'm afraid, unless you want to spend a lot of money - your supply is just inadequate for an unvented cylinder. Was it a certificated engineer who installed it?

You'd be better off having a traditional low-pressure hot water cylinder and a loft tank. Your problem is not related to the expansion vessel.
 
Didn't realise that BB was now G3 competent :rolleyes:

The only pressure he gets is that warm gushing feeling when his Tena lady is full :eek: :LOL:
 
Time to fill bucket at kichen tap is 8.5 litres in 1 minute

Or, to put it another way, cr*p. Serioulsy, I could p**s faster than that. There's very little you can do to cure this really I'm afraid, unless you want to spend a lot of money - your supply is just inadequate for an unvented cylinder. Was it a certificated engineer who installed it?

Muggles - bad news but thx for response. This was a new house so know way of knowing who installed system. I presume after 11 years I have little recourse.

Will the poor flow also be the reason for hot water spluttering out of some of hot water taps initially when taps are turned on.
You'd be better off having a traditional low-pressure hot water cylinder and a loft tank. Your problem is not related to the expansion vessel.
 
How long have you lived in the property? Are your neighbours suffering from the same problem?

It could be down to a restriction in the cold main. It is also possible that all cold outlets come from the balanced supply on the PRV to the unvented unit and the filter is blocked.
 
How long have you lived in the property? Are your neighbours suffering from the same problem?

It could be down to a restriction in the cold main. It is also possible that all cold outlets come from the balanced supply on the PRV to the unvented unit and the filter is blocked.

That could be the case. I would have a new full-bore maintap fitted, clear the filter in case. Then see what it is like. If still that way then a cold water accumulator is the way. This will boost the water to an excellent flow rate at 1.5 bar.
 
How long have you lived in the property? Are your neighbours suffering from the same problem?

It could be down to a restriction in the cold main. It is also possible that all cold outlets come from the balanced supply on the PRV to the unvented unit and the filter is blocked.

That could be the case. I would have a new full-bore maintap fitted, clear the filter in case. Then see what it is like. If still that way then a cold water accumulator is the way. This will boost the water to an excellent flow rate at 1.5 bar.

Thankyou everybody for the advice. What is a full-bore maintap and what will changing it achieve
 
How long have you lived in the property? Are your neighbours suffering from the same problem?

It could be down to a restriction in the cold main. It is also possible that all cold outlets come from the balanced supply on the PRV to the unvented unit and the filter is blocked.

That could be the case. I would have a new full-bore maintap fitted, clear the filter in case. Then see what it is like. If still that way then a cold water accumulator is the way. This will boost the water to an excellent flow rate at 1.5 bar.

Thankyou everybody for the advice. What is a full-bore maintap and what will changing it achieve

The tap has no restriction in it and inside is the same bore as the pipe. Maintaps can reduce flow as it is a big restriction.

Check the filter on the unvented cylinder. Also check the pipe run. Drawn it out. Where does the cold mains pipe run to? Do the cold taps come from the cylinder (just before), etc. How it is piped up is important.

If the cold kitchen tap comes directly from the mains, not via the cylinder, then check the maintap (replace with full-bore) and then check the flow and pressure. If still bad then a cold water accumulator is the only way.

Check what the neighbours is like and try to find out what it was like before you moved in.
 
Check the filter on the unvented cylinder. Also check the pipe run. Drawn it out. Where does the cold mains pipe run to? Do the cold taps come from the cylinder (just before), etc. How it is piped up is important.

Where will I find the filter - not obvious. I can make out the pressure vessel safety valves and stop cock in the vicinity of the cylinder. The sequence of connections on the incoming cold main are main tap, closely followed by a drain valve, then the pressure gauge ( that has a bulky unit on the back of it with a large hexagonal head - could that be a filter ? ). That is all with in 2 feet then the pipe disappears behind the kitchen cabinets.


If the cold kitchen tap comes directly from the mains, not via the cylinder, then check the maintap (replace with full-bore) and then check the flow and pressure. If still bad then a cold water accumulator is the only way.

The cold kitchen tap does not come from the cylinder. As I have a drain just after the main tap would it be advisable to try a flow test from there, bypassing everything else on the cold main.


Check what the neighbours is like and try to find out what it was like before you moved in

One of my neighbours has double my flow but he does have a conventional central heating system, so only mains pressure downstairs
 
Sounds like you have a pressure reducer at the maintap. This may have gone west. If there is a filter there, undo it and clean. Check the pressure reducer.

The neighbours main pressure you are only concerned about, at his kitchen tap.

Screwfix sell a pressure gauge that screws to the washing machine tap. Buy one and test.
 
After wildly bucking around like a crazed horse, BB is finally crawling towards the idea of fault-finding.

nairb999 - I would inspect every component in the path of your incoming mains, and determine whether or not it is contributing to the problem. As you can shut off the supply at the water company's service valve, then you can uncouple at various points and measure the flow rate into a bucket. If necessary, cut a pipe in order to carry out the test and recouple afterwards. But don't cut into any MDPE pipe...
 

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