Low hot water flow rate

[robv]

EDIT: I've renamed this from the original title of 'Ferroli Optima 701 Hot water pressure' In case this is a problem unrelated to the boiler model.

Good evening Ladies and Gents, many apologies if this has been answered elsewhere but I've read the wiki and done a search and still am no closer to finding an answer. I'm no plumber (as i assume are many of your first time posters) but would greatly appreciate the opinion of someone who might help.

We moved into our house a few years ago and the hot water pressure from taps has never been particularly great which has never been an issue as we rarely take baths as we use the shower (where the pressure has appeared fine). The boiler which was already fitted in the house is Ferroli and a sticker inside the front flap says Optima 701 (and indeed it does look like the one here : http://www.aroundtownflats.com/manuals/Boilers/Ferroli/FERROLI OPTIMA 701 GCNo.47-267-16.pdf).

Hot sink taps have always been usable but not certainly strong but hot bath hot tap has always been pretty weak. Cold taps all fine.

However, shortly before Christmas we noticed the water in the shower being particularly cool. After a bit of experimenting we've found that if we use the shower on low water pressure the temp is fine but obviously the flow is low. If we try it on normal flow the hot water is 'drowned out' by the cold water.

Since noticing the shower seems to have lost hot water pressure, all taps remain unchanged. Radiators appear to work fine and need no bleeding.

Boiler pressure is 1bar when cold, rising to about 2.7 when with central heating turned on. Boiler temp set to about 70c, mode is set to 'Heating
continuous and hot water'. I've never had a problem with the boiler itself losing pressure apart from some over-enthusiastic radiator bleeding a few years back which needed a water topup as the pilot went out.

Any ideas what might be causing the low pressure in the shower etc? It seems to be heating the water fine.

 

[robv]

If it helps, it seems to have 'normal' pressure in the shower and warm water for a minute or so before turning cold (when the hot water flow drops).

 

[robv]

bumped with a new title in case the boiler make and model is a red herring.

 

[robv]

Apologies for the shameless bumping, I know it's poor forum etiquette, I've tried to only do it every 24 hours or so. I'll do it this one last time just in case someone sees it this weekend who hasn't been on this week.

Anybody here have any ideas?

 

[Agile]

I, and possibly others have read all your postings but not replied.

This will partly be because your boiler make and model is not seen as very good and often avoided by boiler repairers.

In my particular case I obvious choose which postings I give a reply to and avoid those like yours where you totally mix up and misuse the words pressure and flow. That makes it difficult for me to try to understand what you are trying to explain as my brain tries to interpret what you have written based on trhe words that you have used.

It also worries me that you dont apparently understand that bleeding rads lowers the system pressure ( or flow if you understand that better ).

Tony

 

[robv]

Hi Tony, thanks for your response.

I do understand that bleeding radiators lowers system pressure. Maybe I gave the wrong impression on my first post. What I meant to say was that having bled the radiators that one time I forgot to check that there was sufficient pressure left in the system for the boiler to operate the next time I needed it. That was the only time it's 'failed' on us before. I understand that it didn't 'fail', rather I did, and that that was the only time it has noticeably gone down in pressure while we've lived here.

I guess that if my boiler is not particularly good we may have to consider getting it replaced.

Apologies for possibly mixing up flow rate and pressure. You can probably tell I'm new to this. I was trying to convey that the boiler itself appears pressurised but not a huge amount of hot water is coming out. But what does come out is indeed hot.

 

[Dan Robinson]

Have you checked for a blocked inlet filter (not sure if the boiler came with one).

 

[robv]

Hi Dan, my investigations so far have only been of the order of checking boiler pressure, temp etc. I originally came on here to check if this was a common issue and to see what theories people might have.

Is a blocked inlet filter something a novice can/should check without a professional?

I assume it involves dismantling part of the system to get at the filter?

Edit : after a little googling it appears the inlet filter could apply to either a boiler or shower. Should i be checking the one on Shower, boiler or both?

 

[Dan Robinson]

Both...

 

[robv]

Thought so

I've looked online for guides on how to do this, and indeed whereabouts, for instance, the filter might be found for my shower but so far to no avail. I'll keep looking. If it helps, my mixer looks like this: http://tinyurl.com/robv-mix and my head looks like this : http://tinyurl.com/robv-head

Am i right in thinking that filters are for stopping scale build up? I believe i'm in a soft water area so is this still a likely fault?

 

[Dan Robinson]

They stop it collecting... not forming. But it is not just scale that can get in there.

I did my financial adviser's shower the other day - god knows what was in the water... looked like grey goo, but did a good job of stopping his shower from working.

And that was pumped.

 

[Agile]

It must be good to earn so much that you need a financial advisor to tell you what to do with it.

Private pension, BUPA, ISA, savings plan for children, charity contributions, trusts and a Will!

Buying the freehold of your business premises is alweays a good idea as part of a pension plan is always good. Is that a log cabin in the garden ?

 

[Dan Robinson]

You're Google earthing my old house aren't you

Yes it was - although the council thought it was a shed

Move house since then though bud.

 

[robv]

Tony and Dan, thanks for your help previously. I've had a mate round who works on boilers and together we couldn't see a inlet filter (even though the manual suggests there might be one) so i guess it 's not that that's blocked!

He suggests maybe the heat exchange might have a blockage restricting the water through the system.

I'll try and contact a local Ferroli specialist for a quote.

 

[Agile]

You're Google earthing my old house aren't you

Yes it was - although the council thought it was a shed

Move house since then though bud.

I suppose the business rates are lower on a shed?

In that case you have yet to invite me to the new one!

OP, if you say exactly where you are its just possible that someone who advises on this forum might be able to help you.

But as I said before, many engineers avoid your model.

Tony