Flow rate / regs query

[JD1]

Thanks everyone this was all really interesting to read. I do appreciate you only have my side and have probably had some difficult experiences with customers over the years, but everything I have said is true. I came here to get a bit of clarity and sense check I wasn't going mad to be honest. It has already been a very time consuming 'fight' and when you have been trying to resolve things and negotiate but get nowhere, sometimes you have no choice but to consider taking further action. In short the installer has now, after 5 months, agreed to fit a pump at their cost but is not accepting liability. It remains to be seen whether they actually turn up. Fingers crossed.

 

[chris watkins]

Good luck JD1 I hope things get sorted out to your satisfaction.

Please come back & let us know the final outcome.

Chris

 

[JD1]

Morning.
Thames have been out and say the pressure drop is between street and flat and we've to call the council who manage the block of flats.
Salamander pump has been fitted under kitchen sink where mains is.
Pressure is a lot better but water temperature fluctuation is the new problem. It takes a while to get the shower to the temperature you want but then switches between scalding hot or ice cold. Does anyone have any ideas as to what the cause is?

 

[Riley]

Piped wrong or the thermostatic cartridge has had it

 

[Howsie]

Get someone else in and ask them for a report. If you're getting no joy with the current lot then this will save you a lot of hassle later on down the line.

 

[JD1]

Riley, do you mean the pump itself cartridge has gone or something in shower?
Thanks, we thought about getting another independent person back to do a report.

 

[clemda1]

Morning.
Thames have been out and say the pressure drop is between street and flat and we've to call the council who manage the block of flats.
Salamander pump has been fitted under kitchen sink where mains is.
Pressure is a lot better but water temperature fluctuation is the new problem. It takes a while to get the shower to the temperature you want but then switches between scalding hot or ice cold. Does anyone have any ideas as to what the cause is?

Few things to ask prior to being able to narrow down cause.

1st:
Has the shower been recently installed i.e. with or after the new boiler installation was completed?
If recently installed then Riley is likely correct the pipe work may be installed incorrectly. Solving this can be relatively easy or a complete costly nightmare, providing information on the brand of shower and type of installation (concealed/exposed shower valve) would help us determine this

2nd: If not new a installation, then it is likely the shower you had prior to the combi being installed was designed for low pressure systems only. Now you have pressurised the system the temperature cartridge is not calibrated for the differential in hot and cold pressures that you get from a combi. Especially given the history you have described thus far with the house pressure. A shower valves' thermostatic cartridge is designed with the assumptions that the inlet pressures on the hot and cold will be equal. Your new salamander pump is delivering upto 1.2Bar at upto 12L per minute at the hot taps. But if the cold pressure to the rest of the house is poor as described. At the shower the pressure differential between hot and cold is likely too large for the valve to work correctly hence the fluctuating temperature.
If this is the cause then no real easy fix if the pressure differential is really large.

Confirm what pressure thames water said you are getting at the main stopcock. This should be same pressure as received in the house. The difference will be flow rate. Which could be for a number of reasons. Might just be that the stopcock to our flat may be half closed those reducing the flow. Also check your leasing agreement with he council and see what their obligation to you is with regards to communal utility services/supplies. Should be something there with regards to ensuring there is reasonable amount of pressure/flo to your flat.

Need to solve this problem first or only other option is to fit another pump for the cold water side of the house/or upgrade to another more powerful mains boost system and position it so that we have equal pressure to both hot and cold system

 

[Riley]

I meant the shower piped wrong or dodgy cartridge

 

[JD1]

Hi. Not a new installation for the shower. Was here before but used a pump on the old cold water tank system.

Thames measured 2 bars on the street and 1 in the flat. 14 lpm flow on the street and 8 in the flat (was 7 before the pump was put in).

Still thinking that the wrong type of boiler was put in. We'll have to get them back again. I don't think this saga will ever end!

 

[Riley]

I wouldn't have fitted a combi based on those readings. But the shower fault I doubt is anything to do with the boiler.

 

[Robert Tyrrell]

Easy enough to check the shower really. Just get a cheap replacement from Screwfix (other stores,are available)but make sure it has the same pipe centers, and that it works with less than 1 bar pressure.
You could also fit a shower power booster pump inline, on the cold supply to the shower.
As has been said, if the two sides of the shower don't have a roughly equal pressure then your thermostatic cartridge isn't going to,work correctly.

 

[Riley]

Not sure you can pump an already pumped mains?

 

[Robert Tyrrell]

Not sure you can pump an already pumped mains?

You might well be correct in your assumption there, but what I actually meant to write was:

"You could also fit a pair of shower power booster pumps inline, on the cold supply to the shower in order to bring it up to the same pressure as the hot from the combi."

In my defence I will state that I went to the pub last night

 

[Riley]

I think flow in general is the problem here mate. I don't think you're going to squeeze anything more out of what is already a badly installed boiler

 

[Fowlersrs]

This is pretty simple stuff. Your original installer really has let u down by not taking adequate readings prior to install if the combi. There's no 2 ways about it. They should of atheist made you aware that the boiler would only work at a reduced rate until you resolved the problem with the supply. I would press to get that resolved by the way especially of its not your responsibility as it'll help massively. Adding pumps to combi systems is just a complete work around tbh..

As for the shower pretty sure it isn't combi compatible if it was one with a pump inside on a gravity system. Again another basic check before installing a combi. I've seen them blow completely when put under mains pressure as they're just not designed for it so no wonder it doesn't work.

All in all sounds like you've definitely been let down, get ur supply pressure sorted though and a new combi compatible mixer and you'll be away.

 

[JD1]

Just thought I would update you all.
The company have finally sent a plumber and an engineer out.
The plumber identified that the valve that controls the shower is not a thermostatic control as originally thought.
The hot supply for the shower comes from the combi boiler and takes water directly from the new combi boiler. The old system was set up so the cold water was gravity fed (think someone mentioned it might be this in a reply) from the communal cold water storage tank for the block of flats.

As the hot is running from the combi boiler it has mains pressure whereas the cold water is gravity so does not have a constant pressure as it therefore fluctuates.

If the valve was thermostatic (the shower was already here and worked fine with the old boiler system) it would adjust the amount of hot and cold water coming out of the shower unit to suit the desired temperature.

A non-thermostatic unit doesn’t – it opens each supply by a set amount depending on where you have the dial. As the pressure and flow on the cold fluctuates it will then mean that the temperature of the water fluctuates in turn.

Their solution to this is to re-pipe the cold supply to the shower so that is fed off mains supply. They tell us this will result in a standardised pressure and flow for both supplies which in turn will mean we get a much more consistent shower temperature without it fluctuating.

I suppose the other option is to totally replace all the shower etc and put a thermostatic unit in.

Should they known all this from the original assessment and not put a combi in, in the first place?
Grateful for thoughts if you have some time.

 

[Howsie]

An you'll be wanting a thermostatic shower fitting...