Increase water pressure with Intergas 36/30? Or diagnostics

[HarrietB]

Hi
I've just had an Intergas 36/30 combi boiler fitted and am disappointed with water pressure (less than previous boiler/hot water tank & less than expected). I'm hoping someone may have suggestions to increase pressure so shower pressure is reasonable.

I'm on 3rd floor, London.
Incoming flow rate 11 litres/minute
Flow out is 10 litres/minute
Incoming pressure is 1.5 bar approx.

There are 2 showers - one on 2nd floor, one on 3rd floor and at the moment no way can both work at same time, and even if only one running the pressure is pants.

Any suggestions welcome, or things to check, particularly if they don't cost a fortune. Am looking into mains boost pumps, accumulators & grumfus home boost, but all seem expensive options when I already bought a boiler that I understood would perform more than adequately with the flow/pressure as they are (sadly initial pressure reading of just over 2 bar when decisions were made has fallen to today's 1.5, so maybe that's the problem!).

Am taking advice from the plumber who installed but he suggested I post here too.

Thanks

Harriet

 

[doitall]

Mains boost or put the old system back is about the limit of your options.

Saying that most combi's are only suitable for one outlet at a time, even if you had the pressure and flow rate.

 

[Agile]

Hi

Am looking into mains boost pumps, accumulators & grumfus home boost, but all seem expensive options when I already bought a boiler that I understood would perform more than adequately with the flow/pressure as they are (sadly initial pressure reading of just over 2 bar when decisions were made has fallen to today's 1.5, so maybe that's the problem!).

Thanks

Harriet

From the words that you have quoted it sounds as if you bought a boiler and then asked someone to fit it for you.

If he is on their list of approved installers then I would have expected he would have possibly known about measuring the dynamic flow rate which is the only measurement which is of any use.

Clearly it was not adequate.

An accumulator has limited application and particularly if the mains pressure is not very high.

You should have researched the flow rate from a combi boiler and they are only suitable for one good shower on account of their limited flow rate. Unless 6 li/m of water is enough for your showers. You should have stayed with a tank and hot water cylinder in my opinion but then you did not ask me beforehand!

A mains booster pump will retrieve the situation and I like the Stuart Turner one and they are quite reasonable at about £300.

But a home booster is likely to give problems if you share a mains supply with other flats in the block.

For anyone else the advice is that the suitability of the mains supply must be ascertained by measuring the dynamic flow rate to avoid disappointment.

Tony Glazier

 

[Terry lambert]

Thanks Tony

I have also recommended the Stuart turner pump. I told the customer to come on here to get some other engineers advice so that she had a rounded opinion.

Flow and pressure were measured some time ago, there had been a decrease in both flow and pressure since then with some work to the outside main.

The idea of fitting the intergas was to get the maximum out of the incoming with minimal loss but maybe not the maximum that the boiler could offer, although based on the dynamic pressure measured at the time of quoting, the performance should have been a bit better.

The existing system was very old and would have needed everything from cylinder, boiler and controls updated, plus the customer wanted the space.

The performance is decent for a combi especially being three floors up, it doesn't meet expectations because the customer had a 2 bar shower pump below the bath and was expecting something similar. Expectations were explained

 

[HarrietB]

Thanks All
Helpful to hear thoughts/advice.

Will the stuart turner pump be worse on neighbours than the previous pump (which nobody complained about, but only boosted on bathroom tap)?

And can the pump be used just to boost shower/bath taps and not entire system (unnecessary for the rest of the system - don't want to leech water from neighbours every time the heating/hot water used, and would prefer not to use more electricity than necessary).

Thanks again

 

[HarrietB]

I meant can the stuart turner pump be restricted to just shower/bath output

 

[Dan Robinson]

Had a similar issue with a combi conversion a a few years ago. Despite giving the customer the performance chart and telling him to check that he would be happy with the performance.


Got an earful a few weeks after the job because the bath took too long to fill .


Boiler was performing perfectly when measured after the complaint so obviously he either didn't check or was trying to pull and fast one.


The pump should (imho) be on the incoming supply to do all the flat. Electricity consumption should not be a factor.

I should add that combination boilers can only work to the existing incoming supply. If your old pipes are a mess or you are on a shared supply then your performance will be variable. Thames Water also like to move the goalposts on us as well.

 

[Razor900]

Losing half a bar on the incoming main is very unfortunate and will have a particularly bad impact on the upper floors.

Is the old cistern still in the loft? The easiest solution might be to fit a single impeller pump and run the combi through it. We call it a break tank and pump set up. This will stop it being reliant on the incoming main.

It's not clear whether you are blaming the installer but sometimes things go pear through no ones fault it's just finding a solution that works you have to worry about!

 

[ALEC1]

why do you want simultaneous use of the showers?

In system design there is a concept called coincidence of use...that is peak demand. even big hotels would fail to perform if 100% of baths were opened simultaneously! probably only 40% would be satisfied. hotels know that this just won't happen, the usage will always be staggered. So they don't design systems for maximum demand...

Are you just looking for issue for the sake of it? Are you certain the two showers will be used at the same time.

combis are the most popular form of heating hot water in the UK, and people just get used to the limitations...

they do that because the its a small inconvenience compared to the cost of a high spec system that will rarely get used at peak demand

 

[sweet]

If you are not satisfied go back to what you had before tank & cylinder gravity system & add a pump, the Intergas boiler can still be used & is a brilliant boiler whether used as a Combi or heat only boiler. I get the impression that your hotwater requirement is far greater than any Combi will achieve with adequate water pressure. If your existing system was ageing it's probably a good thing upgrading everything, nothing lasts forever...

 

[Dan Robinson]

Losing half a bar on the incoming main is very unfortunate and will have a particularly bad impact on the upper floors.

Is the old cistern still in the loft? The easiest solution might be to fit a single impeller pump and run the combi through it. We call it a break tank and pump set up. This will stop it being reliant on the incoming main.

It's not clear whether you are blaming the installer but sometimes things go pear through no ones fault it's just finding a solution that works you have to worry about!

Can happen all the time in London.

Don't know where the op is, but there's a lot of chopping and changing of the water pipes.

By brother lived in Clapham North, and they played merry hell when the local supply was upgraded.


Had a customer in Hampstead with naff all pressure when we fitted a convoluted tank and pump set, thrn 6 months later they did the pipes and when we came to change the boilers in in another part of his house ( 4th and 5th floors) the pressure was something like 4 4 bar.


He was exctatic to get rid of the pumps even though it cost him thousands.

 

[HarrietB]

Not blaming the installer - we're both on this forum! I'm asking for advice & opinions so I can make a more informed decision (& not blame the installer!). I really appreciate posts so far, so thank you for taking the time to respond those of you who have, they're really helpful.

Wd like to understand the issues/see if anyone else has suggestions / has tried things that work that we may not have thought of or simply confirms what installer is proposing.

Will appreciate any other thoughts, but prefer to avoid blame please - either me for not being able to understand all the ins & outs that trained plumbers have spent years learning about, or installer. We are where we are and just looking for best outcome!

 

[Dan Robinson]

That's the thing. Your options are limited.

Stored water and pump, accumulator with or without pump or special mains pump.

The later will be the cheapest and smallest solution.

Your boiler will only do 13 litres litres per minute anyway (from memory) so 12 litres from the pump will give you close to the boiler's capacity with the added benefit that the water will be slightly hotter.

 

[Rob]

I'd agree with Alec. What seems like a loss of performance will son be outweighed by the benefits of having a combi.

What type of shower is it? 10 lpm is still adequate for a decent shower!

 

[Deleted member 63160]

Hey Harriet. The Intergas is an upancoming (in this country, established elsewhere I believe) no nonsense brand and suggests by its use that the installer is of a "good calibre". I can say that with honesty as I operate out of Portsmouth for the cheaper end of the market and tbh fit "lesser stuff". Anyone fitting that gear is a thinker and likely a decent bloke. The big problem we have as installers is that we can quote all manner of numbers, stats etc but ultimately the acid test is often when you turn the tap on- is the customer happy? I don't know the guy that fitted your job but from experience I'd say if he fitted that brand he ain't no cowboy.
I'd be inclined to cosy up to him rather than distance yourself and see if you can explore further avenues. Just my twopenneth as they say.
John M.