DHW flow/pressure from my Valliant Ecotec plus 831 r1

[Markjwebb]

Good morning everyone !
This is my first post on here so please bear with me!

I had a shower over the bath running off the bath tap which worked excellently pressure wise but it turned out I had a leak under the bath and the man in the flat downstairs obviously complained so I decided to have my entire bathroom refurbished.
My girlfriend pointed out this steam shower unit which looked cool so I've scrapped the bath and got that instead.
So, the format of my flat mean that the shower is now only 4m from the boiler. I used the existing hot and cold feed into the bathroom and just re-ran it with new pipe to where I need it to be (for the shower and basin.)
Now the problem! When I turn on the shower (either one, the tropical rain head or the hand held) the amount of water that comes out is quite frankly useless!!... I've checked all valves are fully open, the flexi's aren't kinked, and basically EVERYTHING I can think of ?
Could it be that the boiler has lost it's umphf ? I'm baffled and it's driving me MAD! PLEASE please help ???????

 

[bolshy]

Have you checked inlet filters?

 

[Markjwebb]

Hi, thanks for the speedy reply !

No I haven't checked them ? Where re they and how do I do that please ?

 

[bolshy]

On the water inlets to your showering mixer/diverter assembly, generally.

 

[Markjwebb]

Ok, it came with 2 meter long flexis attached that I just connected to the water pipes. Will they be on the shower end of those?

 

[bolshy]

Usually, yes. Unless there are additional flexibles before the thermostatic mixer.

 

[Markjwebb]

Ill check those thank you.

 

[Agile]

Did you ever consider the flow rate that the boiler can give and compare it with what the shower needs? At this time of year your boiler will only manage about 10 litres per minute!

You talk about a "rain shower"! Most of those expect about 15-20 li/min!

You can do some simple flow rate measurements and I expect you will discover the boiler is working fine.

Tony Glazier

 

[Markjwebb]

Hi tony!
The details on the shower say it needs 12 l/m and the boiler boiler details say that at a rise of 35c it should produce 12.7 l/m???

 

[Agile]

With the incoming water at about 5 C then that will give 12.7 li/min at 40 C.

But most people like about 43/44 C to shower. Probably not in your case but many properties can lose 2-4 C by pipework heat loses because only a VERY few bother to insulate hot pipes.

I am surprised if your "rain shower" only needs 12 li/min but lets assume thats correct.

We ( that means you ) then need to do some measurements! You need to measure the hot flow rate at each of kitchen and basin keeping both running and add those together. That will be the open pipe flow rate.

That should be about 12 li/min and would be limited to not much more by the flow limiter in the boiler.

If thats correct then measure the flow rate from your shower. I expect it needs a DYNAMIC flow rate of 12 li/min which means the mains water will need to be sufficient to allow about 1.0 Bar pressure to remain in the pipes when the shower is being used so that the jets are fast to give that tingly feeling.

Unfortunately, very few plumbers understand dynamic flow rates and the implications.

Tony

 

[Markjwebb]

Thanks again tony, I'll do these measurements tomorrow (out on Mother's Day duties all day today.)
The mains water measured at the washing machine (approx 50cm before the boiler) measures at 2.6 bar!
Also, can the flow restrictor be removed to allow more flow? If so what implications would this have?

 

[Agile]

Static water pressure on its own is not much use. Except that it means a new supply pipe would greatly improve the dynamic pressure if it turns out to be poor.

But if you have the gauge, then measure the dynamic pressure while you do those two flow tests.

You need to see what flow rate the boiler is giving. They rarely reduce with age unless there is a blockage.

If the boiler output was restricted then the flow limiter can be removed BUT all that will do is give a greater flow rate but as the boiler does not have the power to heat any more water it will just come out luke warm!

Tony

 

[Markjwebb]

Okey dokey, I'll do all of this tomorrow and repost!
Thanks tony!

 

[bolshy]

+1 on Tony's post. Should be more than a dribble from the hand held spray head though, imo. Even in winter.

 

[gaswizzard]

Ok, it came with 2 meter long flexis ?

What is the internal bore of the hoses? , some of these are useless. , I normally remove them and fit full bore hoses or hard plumb , had a set of hoses supplied with a monobloc basin mixer that were no more than 6mm internal bore.