[Solved] Low shower pressure after ASHP retrofit
Posted by: @jacs@derek-m not sure on the cylinder pressure but the flow drops massively when I open multiple taps, almost to a stop.
When you say that the flow drops massively, I assume this is at the shower head. It would appear that you have some form of restriction that is limiting the flow from or to the hot water cylinder, such that opening more taps will mean that this limited flow is being shared over more 'openings'. Because the shower head is higher than the taps it is more likely that this will lose flow first.
Try turning the shower 'cold' and open some cold taps. If the flow through the shower head remains constant then the problem is not with the shower, but is some form of restriction in the 'hot' pipework.
I would suggest that you check the pipework from the shower head back to the hot water cylinder for partially closed valves or thinner pipework. Also check the pipework from the mains supply to the hot water cylinder.
If, as Johnmo suggests, the problem is due to a pressure imbalance at the shower unit, you should ask your installer to fit a pressure reducing valve on the cold water feed to the shower unit. It should then be possible to set both the hot and cold feed to 3 bar.
@johnmo Hi, please can you confirm what balance flow is?
I turned the shower to cold and opened the cold taps and the shower flow didn't change.
Most mixers uses a balanced flow i.e. the flow pressure from hot and cold is the same. This is how it is normally achieved via the combined valve at the UVC
If you don't have this setup, you really need a check valve on the hot outlet of the cylinder to prevent reverse flow.
The alternative to the balanced flow connection on the combi valve is a prv at the cold water entry to the house set at 3bar or less. Mine is after stop cock, and strainer, then prv then to the rest of the house.
Your cold water test shows it's not a cold issue. So all that is left is the hot water supply. Testing hot on its own isn't really possible because there may always be a mix of cold going into the hot side of the mixer.
Problem resolved - there was a reducing valve under the bathtub restricting flow.
@jacs brilliant. Thanks for letting us know, and glad you’ve resolved it.
Pre-order: The Ultimate Guide to Heat Pumps
Subscribe and follow our Homeowners’ Q&A heat pump podcast
Our newly fitted shower system was regularly running to cold if paused. The excellent plumber fitting the ashp solved it by fitting a pressure control valve on the inlet cold feed.
Different symptoms but same root cause the mixer shower needed balanced pressure feeds. Why the original plumber didn’t fit one is a good question.
2kW + Growatt & 4kW +Sunnyboy PV on south-facing roof Solar thermal. 9.5kWh Givenergy battery with AC3. MVHR. Vaillant 7kW ASHP (very pleased with it) open system operating on WC
-
Yes, the "zoning with ASHP" topic again...
3 months ago
-
My Octopus Cosy 6 Heat Pump Journey: From Quote to Completion
6 months ago
-
Has anyone seen this problem before? Huge anticycling times
9 months ago
-
My British Gas – Heat Force ASHP Installation: A Frustrating Experience
10 months ago
-
Advice needed on inefficient Samsung ASHP installation
11 months ago
- 26 Forums
- 2,122 Topics
- 46.6 K Posts
- 115 Online
- 4,529 Members
Join Us!
Podcast Picks
Latest Posts
-
There are some projects looking at how smart meters and...
By Jeff , 1 hour ago
-
RE: Share Your Experiences with Heat Pump Manufacturer Support
@terry1812 Yes, I use Homely, as to whether Daikin is u...
By Toodles , 14 hours ago
-
RE: ASHP heat output monitoring
@carlo - welcome to the forum. I don't know about LG...
By cathodeRay , 18 hours ago
-
RE: Why do we need pressurised systems?
@old_scientist If that were the case (and it might well...
By Toodles , 22 hours ago
-
RE: 300 Liter Tank - Do I have to heat it all?
There’s no second hand market for DHW tanks (I was told...
By Judith , 1 day ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
We had an excellent four months (11/3 to 15/7) generati...
By JulianC , 2 days ago
-
RE: Is this just haze or something more?
I think the present somewhat cooler hazy days show the ...
By Judith , 2 days ago
-
RE: My misgivings about installing ASHP and solar panels via the ECO4 scheme...
All noted and accepted and as I say I am sorry that you...
By JamesPa , 2 days ago
-
I think it is very much me that is sitting outside the ...
By Grantmethestrength , 2 days ago
-
RE: Replacing Refrigerant on Mitsubishi Heat Pump
@davidalgarve It should just be recovered by both servi...
By dgclimatecontrol , 3 days ago
-
RE: Who's your electricity provider and what's your tariff?
Aggregators have been recognised for many years, and it...
By Transparent , 3 days ago
-
RE: Help me keep the faith with my air source heat pump installation
Great news I edited my previous post (probably af...
By JamesPa , 3 days ago
-
RE: Double or Triple Glazed Windows?
@toodles Glad to hear things are progressing well for y...
By TRBob , 3 days ago
-
How to waste energy (and time) playing with AI.
A friend of mine who subscribes to an AI service was ex...
By Toodles , 4 days ago
-
RE: Heat Pump Books For Beginners – Bodge Buster & From Zero To Heat Pump Hero
@topher you’re more than welcome to, yes. I’ll send you...
By Mars , 5 days ago
-
RE: Fitting new shower valve ..........
I’ve never taken a chance when fiddling and changing ou...
By Mars , 5 days ago
-
You should contact the council and report the unsatisfa...
By JamesPa , 5 days ago
-
RE: Benefits of an extra horizontal loop for GSHP
I would deffo install an additional slinky run, especia...
By Transparent , 5 days ago