Low water flow

[Campo73]

Hello all I'm hoping for some advice regarding the plumbing installed into our newly renovated house.

We have installed an unvented system, the water pressure at the street is 3 bar. The pressure gauge on the water cylinder is reading 1.5 bar. My first question is why does the pressure gauge at the water cylinder not read the same as the street?

The water flow is what I would consider very average. These are the measures I have taken by filling a bucket for one minute:

ensuite shower 9l/m
ensuite tap (restrictor removed) 11.5l/m
bathroom tap 8l/m
bathroom shower 12l/m
bath-takes 18 minutes to fill to the overflow.

Copper pipe has been installed and we think it is 22mm. The spec for the ensuite shower states maximum flow 17l/m at 3 bar. The flow seems very poor and we are only getting half the spec.

I'm hoping someone can shed light on this and give me some non technical advice,I am just a layman so apologies if what I have written omits some basic information.

Many thanks in advance.

 

[magicno1]

Most cylinder manufacturers want roughly 2 bar pressure but more importantly around 20ltrs a minute!
did your plumber do a pressure and flow test before specifying the unvented tank?????
what size and how old is your incoming water main pipe???? If it's old half inch iron you have had it basically unless you replace from the mains outside to give more flow!
you may only have 12/13 ltrs min coming in and 22mm pipe inside ain't gonna make any difference I'm afraid!
you need to check your supplies and ask your plumber if he tested first!
is the pressure gauge after the pressure reducing valve at the tank?

 

[Riley]

Could the pressure gauge actually be a remote pressure device for a boiler??

 

[Campo73]

Hi thank you for replying. We have replaced the water pipe right to the street. I'm not 100% sure what size it is but it looks bigger than 22mm. I will ask they they did a test before installation.

Actually it does look like the gauge is after the pressure reducing valve. It seems to be on the pipe which feeds the underfloor heating system. However the pressure reducing valve also is before the split in the pipe. The split one way is 22mm and the other way towards the underfloor heating pipes appears to only be about 10mm.

The he pipe coming directly out of the cylinder also only appears to be 10mm and then after the pressure reducing valve it changes to 22mm before it splits into two as described above.

I I checked the shower again tonight and when I intially turned it on the flow was slightly improved. Within seconds it lost flow and then when i turned the sink tap on the flow was woeful.

Would appreciate anymore advice, am feeling a bit out of my depth. Usually I would read up to understand the problem but I can't find the answer, plumbing seems very complicated.

 

[Riley]

Could you explain your heating set up. What boiler, you mentioned cylinder, any other components

 

[Campo73]

Hi Riley

Yes the boiler is a greenstar 40CDI Classic regular and the water cylinder is a Norman cylinder. I think it has an expansion tank. Does that help at all?! I was surprised to see the 10mm pipe coming out of the cylinder, is this normal?

 

[Riley]

10mm, really!?

gonna need some piccies of that cylinder mate.

Set up a dropbox account and add a link to your pictures. I don't believe any plumber would install that set up in 10mm

 

[Gray0689]

Hi Riley

Yes the boiler is a greenstar 40CDI Classic regular and the water cylinder is a Norman cylinder. I think it has an expansion tank. Does that help at all?! I was surprised to see the 10mm pipe coming out of the cylinder, is this normal?

No it should be 22mm from a Norman cylinder this must be a pretty new instalation
As above please can you post up some pictures of the set up

 

[Campo73]

I don't seem to be able to post the link, maybe it's because I'm new to the forum? I'll try one more time in the next post. Gray0689 it is a new system, we have fully refurbished and extended the house. All the plumbing is new, we haven't even moved in yet. We are in Belfast by the way, I see you are in Northern Ireland.

 

[Campo73]

Link to photos

https://db.tt/fr6Lur7P

 

[PlumbBobBob]

campo we need a piccy of the top of the cylinder as well

 

[SJB]

The pressure gauge will be showing the heating system pressure. An unvented cylinder will most likely have a 3 bar pressure reducing valve on the cold mains to the cylinder.

 

[Gray0689]

Yes mate I'm NI it looks like a GLO underfloor system from the zone manager you got it from Bassetts I presume
Like said take a pic of the cylinder please
The gauge you are looking at is the heating pressure not the water pressure

 

[SJB]

Make sure the internal stopcock and the external stopcock are both fully open...

 

[Gray0689]

The 10mm actually 15mm is the blow off from your TP relief valve from cylinder
Your hot draw off is at very top of cylinder
I think the pipe work your referring to as 10 mm on tee is the blow off from the combination valve (which is wrong anyway should be before the tundish )

 

[Best]

The combination valve should really have been fitted higher (normally at or a little higher than tank) for servicing & to allow the blow off pipe to fall down to the rest of the D1 pipe, all above the tundish. It is G3 regs - all the discharge pipes must fall from the relief valves.
The work looks neat though!

 

[Riley]

Several issues with that install, easiest answer is get in a G3 registered engineer to look at the pipework for you and they should be able to collect the flow for you if both stopcocks are open

 

[Campo73]

I'll get a photo of the top of the cylinder. According to NI water there is 10+ gallons water flow coming in at the street. That seems to be 45 litres by my calculation.

Will ly I find such a G3 registered engineer in the yellow pages and hoe much would it cost for someone to come out.

Many thanks for for all the replies, unfortunately some of it is over my head but I can appreciate there seems to be a problem with the install!

 

[Campo73]

I should add yes it is Bassetts design although I've never seen the spec, they wouldnt give it to me.

Best- which bit is the combination valve? Does anyone know where I can get a photo/diagram of what how it should actually look on this type of cylinder?

thanks again everyone, I really appreciate the help, not feeling quite as lost now!

 

[Campo73]

Riley-are you able to state what the 'several issues' are so I can understand it all a bit better? Thanks again for taking the time to post.

 

[Best]

Best- which bit is the combination valve? Does anyone know where I can get a photo/diagram of what how it should actually look on this type of cylinder?

thanks again everyone, I really appreciate the help, not feeling quite as lost now!

The combination valve usually has the pressure relief valve built on it (normally this relief valve has a red head on it). Tbh I can't make it out on your photos well.
A G3 qualified guy is simply someone who has done unvented exam.
The installer should come back to it.

 

[Riley]

Riley-are you able to state what the 'several issues' are so I can understand it all a bit better? Thanks again for taking the time to post.

A couple of the faults were mentioned earlier in the thread and I'm sure you'll appreciate that it's not something I'm keen to spell out too much as it's something that should only be looked at and altered by someone suitably qualified. Not a diy fix I'm afraid. But you could tell the engineer that the safety pipework has been plumbed incorrectly

 

[Best]

^^^^ I agree with above totally. You are not supposed to do any work to unvented unless you are qualified - it's the law in UK.
You say you have poor flow & there is a few things that are best redone, so you are best getting the installer to come back. He has done what looks to me to be neat work, which is rare.
On the point of asking for a diagram to show the supposed layout, - don't worry about that as the installer if he is G3 will know what the proper layout is. The MIs state a lot of it anyhow.

 

[Campo73]

Thank you Riley I will certainly be mentioning the fact the safety pipe work is incorrect, that sounds serious. I have no intention of touching any it, I am a middle aged woman simply trying to understand why none of the plumbing works. Having looked again today the underfloor heating manifolds all show the indicators at zero even when I turned on the thermostats in the rooms. The shower in the ensuite does not run completely cold when I turn the mixer fully to cold. The radiator in one of the front rooms does not heat up properly even though the thermostat is at 5, it is still lukewarm. It seems I have a multitude of problems. I have added more photos to Dropbox showing the top of the cylinder, the underfloor heating pipes and the boiler. I will go back to the installer initially but have lost faith in him somewhat.

 

[Campo73]

I can't remember whether I already said it but I checked the stopcocks and they are fully open. Again I can't understand why the flow coming in is 45+ litres but in the shower it is only 9 litres. link to folder with additional photos - https://db.tt/fr6Lur7P