Low pressure/low flow

[Simon Read]

Hi All,

I live in a 400 yr old house although the pipework is only 3yrs old from the internal stopcock. I have a low water pressure / low flow problem that I wish to sort out. It's a 25mm incoming pipe stepped down to 22mm internally which then reduces to 15mm into the various taps. I have a PRV with pressure gauge fitted to the system as I wondered what the pressure was. I have a systemic pressure of 3.5bar which reduces to 0.7bar with one tap on. With 1 tap on I get a flow rate of just over 12lpm (only have a 12ltr bucket which fills up in 50sec)

With 2 taps on I get a dynamic pressure of under 0.5bar and a flow rate of 9.5lpm. Both of these taps are downstairs. My problem is that the upstairs electric shower struggles, presumably because of the low flow/pressure. It's a low pressure shower working on a minimum of 0.7bar. Its not too bad until someone flushes a toilet, then it just doesn't recover at all. It has to be turned off until the toilet stops filling then can be turned back on again. The downstairs mains fed shower works perfectly, regardless.

My boiler is an oil fired worcester bosch greenstar.

Is it worth contacting the water board or should I look at a flow pump like the salamander?

 

[Simon Read]

Hi Simon.

I'm glad that a simple removal of the PRV has improved your situation.
I'd like to point out though that an excessively static pressure can damage seals/washers on a combi boiler, do you know the now static pressure?

Hi, I don’t I’m afraid no. The PRV that was on it had a pressure gauge on it. I never saw this go above 3.5bar (static reading) however I’m not sure if it was showing that as the PRV was set to 3bar or wether that was the actual static pressure of the system.......

 

[SJB060685]

That reading is most likely what the PRV was set to allow as maximum.
If its been a number of weeks without problem then touch wood it should be holding.
If you took the front of the boiler off and inspected around the PHX and cold mains pipe that is where you might encounter problems

 

[Ric2013]

That reading is most likely what the PRV was set to allow as maximum.
If its been a number of weeks without problem then touch wood it should be holding.
If you took the front of the boiler off and inspected around the PHX and cold mains pipe that is where you might encounter problems

If the OP isn't a registered gas installer, then probably best he doesn't start taking the boiler apart?
Agreed that the 3.5Bar is probably what the PRV was limiting the pressure to.

 

[Simon Read]

If the OP isn't a registered gas installer, then probably best he doesn't start taking the boiler apart?
Agreed that the 3.5Bar is probably what the PRV was limiting the pressure to.

Hi, no I’m not a qualified plumber. My system is an external oil fired combi system though. I fitted the whole system myself before having it all signed off by a qualified plumber so I’m pretty familiar with the system. I’ve looked and not noticed any leaks at all around the boiler or various other parts of the system 👍🏻

 

[SJB060685]

If the OP isn't a registered gas installer, then probably best he doesn't start taking the boiler apart?
Agreed that the 3.5Bar is probably what the PRV was limiting the pressure to.

In his original posts the OP stated it was an oil combi. If it was a gas boiler obviously I would not suggest removing the cover but as its oil, the fact the OP has already demonstrated a good understanding and the boiler casing has to be removed in order to access the filling loop by the end user im confident the OP could give a quick check of what i suggested without putting himself, family or system in danger.