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hi 

 

i have a unvented system in the loft, mains into the house is MDPE PIPE BLUE 25MM this goes into a PRV and then onto the unvented tank.

 

My pressure is not very good, unfortunately my PRV doesn't have any gauges so i cant tell what pressure is in/out but when showering its low pressure.

 

I have been looking at 3 systems to boost the pressure.

 

1. Boost a Main

(19) Boost A Main Power - YouTube

Home | Boost-a-Main

 

2. Stuart Turner (pumped)

Mainsboost MB 200SH-1-22 | Hot Water Cylinder | Stuart Turner (stuart-turner.co.uk)

 

3. Salamander

AccuBoost Accumulator Tanks | Salamander Pumps Mains Booster Range

 

all 3 seem to use a accumulator that is pumped, the pumped part seems to be the main difference with Boost a main on the youtube video looking really powerful.

 

Does anyone run any of these systems on a unvented system, does it really increase pressure much??

 

any help of advice would be great

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I have dab pressure main booster on mine. It's easy to Install, I've had for 3 years and really pleased with it.

 

It uses a small pressure vessel to keep system pressurised and pump kicks almost simultaneously as you turn a tap

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57 minutes ago, tomcoleman said:

My pressure is not very good, unfortunately my PRV doesn't have any gauges so i cant tell what pressure is in/out but when showering its low pressure.

Perhaps the PRV is not working correctly. Doesn't the PRV have a block with a threaded hole for connecting a pressure gauge. Without knowing the pressure I don't see how you can find the best solution, maybe adjusting the PRV first just to see if it's working.

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If you have a PRV the pressure must have been too high at some point in the past. I find PRV need adjusting every say 5 years. Over time the flow rate reduces until I get fed up and turn it up. There is usually a screw on the end, sometimes hidden under a lable. 

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Don’t mix up pressure and flow rate, you can have good pressure but p*** poor flow rate if there is a restriction in the line (PRV, shower valve or small bore piping). Boosting the pressure won’t improve the flow rate if this is the case. Agree as above, you need to measure the pressure and try adjusting the PRV before spending any money...

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Posted (edited)

thanks guys, my PRV doesn't have a pressure hole for some reason so i would need to swap that over to a version that does.

 

attached is my PRV any ideas on what model to replace with ?

 

on the other side is another port which goes off to a mini expansion vessel

 

 

 

 

PRV.jpg

Edited by tomcoleman

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12 hours ago, GaryM said:

I have dab pressure main booster on mine. It's easy to Install, I've had for 3 years and really pleased with it.

 

It uses a small pressure vessel to keep system pressurised and pump kicks almost simultaneously as you turn a tap

 

looks interesting - was this installed on a unvented system ?

 

Is pressure on shower strong ? what's it like or just normal 

 

if you can expand on this would be great

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11 hours ago, PeterStarck said:

Perhaps the PRV is not working correctly. Doesn't the PRV have a block with a threaded hole for connecting a pressure gauge. Without knowing the pressure I don't see how you can find the best solution, maybe adjusting the PRV first just to see if it's working.

 

11 hours ago, Temp said:

If you have a PRV the pressure must have been too high at some point in the past. I find PRV need adjusting every say 5 years. Over time the flow rate reduces until I get fed up and turn it up. There is usually a screw on the end, sometimes hidden under a lable. 

 

going to try and swap out PRV with a pressure gauge version

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you might try opening it and checking it's strainer too..

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18 minutes ago, dpmiller said:

you might try opening it and checking it's strainer too..

 

i have opened up the PRV and strainer which was clean. I have adjusted the setting on the PRV but seems it was already on max (3bar) and has made no difference 

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Posted (edited)

Do you have room for an accumulator? 300l would be the minimum to install if you want a decent uplift. 
If not, then it’s a pump set. Accumulator is silent and near zero maintenance, so I’d at least consider that first. It can be in an outbuilding/ garage / other. 
Go to screwfix and get a pressure tester for a couple of tenners, and connect it to the outside tap or was home machine valve. Report your reading here. 

Edited by Nickfromwales

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3 hours ago, tomcoleman said:

 

looks interesting - was this installed on a unvented system ?

 

Is pressure on shower strong ? what's it like or just normal 

 

if you can expand on this would be great

It's on an invented system.

 

We had a low flow rate around 9ltper min, with low pressure around 1.2 bar.

 

It's increased flow rate a little, but pressure is great, we have it set to 2.5 bar, it could go higher.

 

We have a combination boiler and can see a really noticeable difference, shower is great even from a rain head with our slow flow rate. Put it this way, if we stay away we like to come home to have a good shower.

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I should point out I have no tank, just a combination boiler that feeds hot water, Ch and ufh

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4 hours ago, tomcoleman said:

I have adjusted the setting on the PRV but seems it was already on max (3bar) and has made no difference

It doesn't look like a new setup, so has it always been poor. How long have you been using the system like that. I would measure the pressure and flow rate.

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5 hours ago, tomcoleman said:

thanks guys, my PRV doesn't have a pressure hole for some reason so i would need to swap that over to a version that does.

 

attached is my PRV any ideas on what model to replace with ?

 

on the other side is another port which goes off to a mini expansion vessel

 

 

 

 

PRV.jpg

 

 

Sorry if Im being slow but..

 

All the pressure regulator/reduction valves I've ever had were two port (eg in and out) .  Can you tell us where each of the pipes on yours goes?

 

 

 

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1 hour ago, Temp said:

 

 

Sorry if Im being slow but..

 

All the pressure regulator/reduction valves I've ever had were two port (eg in and out) .  Can you tell us where each of the pipes on yours goes?

 

 

 

That is more than just a simple PRV.

 

Cold raw mains in one side.  Pressure reduced out to the HW cylinder the other.  The 22mm from the bottom is cold pressure reduced water out to feed the cold taps so they match the pressure of the hot, and the 15mm is the vent from an over pressure relief valve to a drain via a tundish.

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On 05/03/2021 at 09:02, Nickfromwales said:

Do you have room for an accumulator? 300l would be the minimum to install if you want a decent uplift. 
If not, then it’s a pump set. Accumulator is silent and near zero maintenance, so I’d at least consider that first. It can be in an outbuilding/ garage / other. 
Go to screwfix and get a pressure tester for a couple of tenners, and connect it to the outside tap or was home machine valve. Report your reading here. 

 

outside tap is on the side of the house (ground floor) unvented tank is on the top floor (3 floors up) so pressure reading on the outside tape would be a false reading? I think i need to change the PRV over and then get the mains pressure reading in at the loft where it then enters the unvented tank.

 

nick can you explain what you mean by pump set?

 

so far from what my little brain can understand is i either put an accumlator next to the megaflow in the loft (pumped version) max 200L or connect a pump somewhere directly? is that right?

 

Im not sure on the latter as i thought you cant connect pumps to a unvented megaflow type system as it could explode or collpase in on itself, or is the pump set you mentioned something different? 

 

please see my 3 links on the first post these are the ones / systems i have been looking at.

 

22 hours ago, GaryM said:

It's on an invented system.

 

We had a low flow rate around 9ltper min, with low pressure around 1.2 bar.

 

It's increased flow rate a little, but pressure is great, we have it set to 2.5 bar, it could go higher.

 

We have a combination boiler and can see a really noticeable difference, shower is great even from a rain head with our slow flow rate. Put it this way, if we stay away we like to come home to have a good shower.

 

ahh mines unvented with megaflow type tank.

 

18 hours ago, ProDave said:

That is more than just a simple PRV.

 

Cold raw mains in one side.  Pressure reduced out to the HW cylinder the other.  The 22mm from the bottom is cold pressure reduced water out to feed the cold taps so they match the pressure of the hot, and the 15mm is the vent from an over pressure relief valve to a drain via a tundish.

 

correct.

 

the flow is this.

 

Mains street pipe comes into house and upto loft, which goes from MDPE to copper into the PRV (as photo shows cold mains is coming from the right in that picture) 

 

mains > PRV > PRV to megaflow (reduced 3bar) the other ports on the PRV go to a expansion vessel and then theres a cold return loop.

 

I have a feeling i need to swap over the PRV with 2 guages to then see what mains pressure in is (at 3 floors high) and what pressure is being delivered to the megaflow tank in the loft.

 

I presume with such a high run to the loft the head pressure is shite which is effecting the rest of the system.

 

I have a horizontal megaflow tank i do have space for a accumulator but max around a 200l version which i could site next to the megaflow tank.

 

 

 

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I’ll reply in depth when I finish getting this last 1/2kM of cable in here. :S 

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placed my ordered todo for a Provess 440H and a Boost-A-Main MSP10 pump will let you know how it goes.

 

Over £3k of kit ! 😫

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3 hours ago, tomcoleman said:

placed my ordered todo for a Provess 440H and a Boost-A-Main MSP10 pump will let you know how it goes.

 

Over £3k of kit ! 😫

Not cheap that business is it. Glad I shelled for the extra cost of some 32mm mdpe here

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On 20/03/2021 at 12:42, Oz07 said:

Not cheap that business is it. Glad I shelled for the extra cost of some 32mm mdpe here

 

i also put in MDPE pipe in replacing the mains into the house direct into the water supply off the road, made no differnce. mains into house is 2bar.

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You can't increase static pressure, regardless of pipe size.

 

The increased diameter will allow for more dynamic / working pressure, though, at a given flow rate.

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6 hours ago, fezster said:

You can't increase static pressure, regardless of pipe size.

 

The increased diameter will allow for more dynamic / working pressure, though, at a given flow rate.

 

The pump charges the accumulator though up to 6 bar....? 

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46 minutes ago, tomcoleman said:

 

The pump charges the accumulator though up to 6 bar....? 

 

Yes, a pump can be used to increase the static pressure. I thought you were saying you increased the pipe size to the road and saw no increase in static pressure - you wouldn't expect to. Sorry if I misunderstood. 

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