Combi boiler delivers hot water then luke warm

[DP]

The guy could be right. To confirm you need an expert Vaillant man
Not for the first time have power flush needs been blown out of water

 

[Steelmasons]

Rubber hose is more than likely choked solid.

 

[Steelmasons]

So has he replaced the DHW heat ex?? 'Cos that what he needs to do!

Not necessarily..

 

[chrispalmer1977]

Oh come on! It's the most common problem in this situation! The rubber hose is a good call but there would be no heating either...every job I've been to with these symptoms has been the plate h-ex! Bet there's no scale reducer fitted!

 

[chrispalmer1977]

If it was a blockage on the heating side, it would most likely overheat and lock out...it's not.

 

[Steelmasons]

 

[Steelmasons]

Oh come on! It's the most common problem in this situation! The rubber hose is a good call but there would be no heating either...every job I've been to with these symptoms has been the plate h-ex! Bet there's no scale reducer fitted!

The burner will ramp up for hot water and quickly shut down when hose choked/restricted.
Burner ramping up/down won't be such an issue with heating only , especially so if heat load has been down rated in d.0..
Have you never had to replace a blocked hose/s?

 

[chrispalmer1977]

Yep! It's the only thing I don't like about those older vailants...I'm my experience it's affected both CH and HW when the rubber hose is blocked... not saying it wouldn't be that tho buddy.

 

[spiritusuk]

Just spent the best part of an hour trying to calm my 88 yr old mother down as she has been on the verge of tears borne out of frustration.

The engineer attended again today, left a form for my mum to sign and left with the understanding that he would speak to me later in the afternoon to explain what has
been done.

I visited my mum after work and start running a hot bath to test. Within a few minutes it was clear that the original problem remains i.e. hot water for a couple of minutes then luke warm at best. Turning the hot tap off, waiting a minute or two and then opening tap gives another short burst of hot water but not really a solution.

I read the form he left with my mum which had two recommendations "re-pipe required" and "powerflush". The power flush recommendation irked me a but as he told me himself on his earlier visit that a power flush would be a waste of time due to the narrow pipes i.e. 10 mm plastic pipes to all rads.

I spoke to him a few moments later and he explained he had taken out and cleaned the secondary heat exchange (?) and I think something else but can't flipping remember what now as I wrote it down at my mum's house ! He also used some chemicals to flush the boiler which he said could taken between 1-2 weeks before it works it's way fully through the system.

I explained that the hot water is no better than it was before we called British Gas out and he said to give it 1-2 weeks for the chemicals to flush the system out and ring him then if there are still problems.

We then had a discussion about the best course of action and he said we need the system re-piping. He made a remark that we should follow BG's advice if we are paying them as they are professionals (or words to that effect). I pointed out that if every BG engineer that worked on our boiler gave the same diagnosis and the advice was consistent throughout then we would happily listen AND pay but one engineer says one thing and the other says something else. I wouldn't want my mum to pay for re-piping and then the system not work because BG decide that the water pressure into the property is too low or some other reason.

I've had a suspicion that the plastic pipes to the rads are too narrow based on everyone else's piping that I come across. Sad I know but I actually notice the piping width when I'm in someone else's house now

The house is a large'ish 3 bed terrace with 7 radiators. Do you agree that 10mm plastic piping is not sufficient ?

After I spoke to the engineer another question popped into my head which I hope someone here can kindly help with. The combi boiler is directly behind my mum's bath (in the room nextdoor on the same wall). Would narrow plastic piping or sludge in the piping affect the temperature of the water on the other side of the wall ?

Thanks guys and sorry for the epic but it's been a stressful evening and wanted to get this off my chest.

 

[picasso]

Why are the recommending a repipe of the rads to sort out a hot water problem ?

 

[ianmcd]

what difference would the diameter of the pipes to the radiators make to the Hot water, I am afraid you have a shoite so called engineer that does not have a clue what he is talking about, call BG customer services and demand that it is repaired within seven days or you will get the boiler manufacturer out and send them the bill, the problem is within the boiler it has nothing to do with the radiator pipe work

 

[BGLucky]

Whereabouts does your mother live? If you have an issue with the engineers advice then you could call customer relations and they will pass onto a manager.
It does sound like he has had his work cut out but nether the less you need some definitive diagnosis in order to decide the best course of action.
Are any or all of the radiators heating up ok when they are on?
If you have a WR number off of the paperwork I could get someone to call you tomorrow.

 

[spiritusuk]

That's what I was thinking after I had spoken to him

Whereabouts does your mother live? If you have an issue with the engineers advice then you could call customer relations and they will pass onto a manager.
It does sound like he has had his work cut out but nether the less you need some definitive diagnosis in order to decide the best course of action.
Are any or all of the radiators heating up ok when they are on?
If you have a WR number off of the paperwork I could get someone to call you tomorrow.

I would prefer to keep it anonymous on this forum at least but thank you

We don't have any problems with the engineer as such-he's polite, friendly and to be fair has spent quite a few hours now on the boiler having made 3 site visits in the space of a week. However, we don't seem to get any consistent advice from BG. Even he contradicted himself by telling me a power flush on a 10mm pipe would be a waste of time but then including "power flush" as an advisory note on the paperwork he left my mum.

I know ZERO about plumbing but wondered afterwards why the plastic piping around the house which he advised needed to be replaced with a wider diameter would be affecting the hot water in the bath on the other side of the wall from the boiler.

I presume you work at British Gas ? Can I make a suggestion ? Please can the documentation which the engineer hands to the customer receive a massive make over as at the moment it comprises of a few scribbles from the engineer and no detail ? It has been like this with every single engineer who has checked the boiler.

With the two most recent comments on this thread I am now wondering whether a re-pipe job would fix the problem with the hot water. If my mum went through that expense and mess and still had the same problem I would be seriously worried about her health.

Some of the radiators struggle to get hot so perhaps a re-pipe would solve that BUT the call out was related to hot water and not hot radiators.

 

[chrispalmer1977]

This is all total rubbish and so frustrating! These guys clearly have no idea what they are doing! They won't be happy until they have re-plumbed the whole house, replaced the boiler and taken all of this poor woman's money!! Disgraceful!!

I'd be interested to know where u are too?

 

[Steelmasons]

For the cost of a hose @ 12 notes then a no brainier........allow 120 notes for labour and problem solved...