Useless tradesmen

[EEPhil]

According to "The Nottingham Post"

Severn Trent is advising its customers to take showers rather than baths - and only to wash certain parts of their cars - as water usage increases 'significantly' during the hot weather.

Great!
Climbed into the shower this moring. Gurgle, spit, bag - "Low Pressure" warning. Reset the damn thing. Same again - followed by "Service" warning. Tramp downstairs to the main stopcock to check it's fully turned on. Try again - no water (there was in the taps).
OK. What is the cause of the problem? The useless people who turned up yesterday to fit a new boiler. This meant rearranging some of the pipework. It didn't mean stick your saw through the pipe to the shower and disconnect it. It must have been slightly more complicated than that as there wasn't water gushing from an unterminated pipe. You'd think these plumbers would know their way around the pipework. . What a "Hon. Member for Haltemprice" that person was. What a bloody shower - well, not in my case - the company is.

 

[Black Hole]

I assume you will tell them that in no uncertain terms!

 

[dandnsmith]

You'd think these plumbers would know their way around the pipework

I guess I'm fortunate that my most recent plumbers aren't above asking if I know about certain pipes - but then I am present , so I can be asked.

 

[EEPhil]

Turns out the stupidity goes beyond the current plumbers.
Some sort of feeder tank for the central heating was added at some point. The new system doesn't need it, and so was disconnected.
In the meantime, a different set of useless workers revamped the kitchen/bathroom/toilet of this house. In doing so they replaced a shower fitted many years ago by East Midlands Electricity Board. Instead of using existing pipework they took a feed from the output of the feeder tank.
The current plumbers didn't check the pipework and so disconnected the shower. They also didn't finish the job properly and so came back on Friday to fit some radiators. Did they do the job properly? Did they heck! Boiler shows lack of water pressure ( 0.4 bar). I put my engineering hat on and had a good look round to find an added tap which appears to replace the need for the feeder tank. Added a bit of extra water to the system and now 2.0 bar, but dropping today to 1.9.
The joys of living in rented accomadation - no choice over which numpty visits next.

 

[Black Hole]

The "feeder tank" you describe is the header tank, which used to be the system for maintaining the CH circuit at pressure (I don't know why a CH circuit needs to be at pressure). It would have had a mains feed and a ball cock to keep it topped up, and an overflow. Ball cocks need maintenance (as per a toilet cistern, but usually less accessible. Indirect hot water systems similarly had a much larger header tank to provide pressure to the hot taps.

Replacing the boiler, no doubt you now have a combi. Presumably for easier original installation these use a pressure vessel instead of a header tank, and if you take the front off you should see a pressure gauge for the CH circuit, and a cock to open a feed from mains pressure. Mine is set to 1 bar, and needs topping up occasionally (from the cock).

The trouble is these combis are to clever for their own good. Yes, they are designed to be more efficient that the old fashioned boilers, but there is a lot more to go wrong. By default, the boiler runs the CH circuit. When there is a hot water demand, a diverter switches the flow from the external CH circuit to an internal heat exchanger through which the mains water flows on the way to the hot water tap. The diverter can fail, the heat exchanger can perforate and lose pressure from the CH circuit. These things play havoc with the sensors and the boiler starts cycling or shuts down. Lots of unions inside the casing can weep and corrode the innards (got the t-shirt).

Your lot sound like a real bunch of cowboys. I protect myself by knowing at least as much as they do, or asking questions until I do.

If you get any trouble from the boiler, your first port of call is to check the pressure gauge and top up if necessary. If you find yourself topping up more than reasonable, suspect a leak in the heat exchanger.

 

[MikeSh]

Heating systems need a bit of pressure because when the pump runs it produces a negative on the suction side. That can have various undesirable effects, so ideally the system pressure should be at least x psi above atmospheric where x is the pump pressure.

With combis or normal sealed systems (ie. without a header tank) the radiator circuit is also part of the pressurised system. Loss of pressure / leakage is more likely to be in the valves and joints outside the boiler than the heat exchanger.
I avoided going sealed in our current house as the heating system is 25 years old and not very 'tight'. I put a new header tank in as part of a conversion to mains pressure hot water (our shower and bath requirements would require a massive, expensive and less efficient combi).

 

[Black Hole]

With combis or normal sealed systems (ie. without a header tank) the radiator circuit is also part of the pressurised system. Loss of pressure / leakage is more likely to be in the valves and joints outside the boiler than the heat exchanger.

I've never had a problem with the external circuit. Several times I've had problems with the heat exchanger, so either my experience is unusual or...

I've even had a replacement pressure vessel!

 

[MikeSh]

Well, when combis first came to the UK the traditional British boiler makers got on the bandwagon - on the cheap of course. So a lot of people got lumbered with units built with unsuitable materials and designs. The continental brands, like Vaillant, were generally OK because they had a lot of experience.
I think things have improved since then, if only because some of said brands got bought out by the 'foreigners' and have upped their game as a result.

 

[Black Hole]

Well, my "Worcester" is actually a Bosch, so work that one out.

 

[prpr]

I avoided going sealed in our current house as the heating system is 25 years old and not very 'tight'.

That sounds like my current system, except it's 31.

I put a new header tank in as part of a conversion to mains pressure hot water

I want that as well. What system type have you got? I want store pressurised HW. I hate the thought of a combi.

 

[dandnsmith]

After a recent foray into buying new taps, I learned that 'mains pressure' can vary quite a lot - indeed, parts of Maidenhead have, for years, been complaining about low mains pressure. What pressure you have will influence whether you have a sealed system - as I have had now for 18 years - and no header tank (think about the head of water needed to mimic mains pressure in a high pressure area).
Until I had a bathroom overhaul, one shower took a mains pressure feed, making it too painful to use (except for my wife's brother who seemed to think it quite usable). There must now be an additional pressure reduction arrangement (I don't know how this was done), so all is usable.
My main problem for the last few years has been pumps - in the last cold spell a 6 month old, very fancy pump which ramped up the feed and was really noiseless, failed. The previous pump to that had also to be replaced after not a vey long life. Now I view with apprehension any parts of the system which include electronic controls (that recent pump did).

 

[Black Hole]

I want that as well. What system type have you got? I want store pressurised HW. I hate the thought of a combi.

An old-fashioned (but well insulated) hot cylinder is the way to go - my mum has solar collectors on the roof with a heat exchanger coil in the hot tank (along with an immersion element).

 

[MikeSh]

I want that as well. What system type have you got? I want store pressurised HW. I hate the thought of a combi.

My main problem for the last few years has been pumps

In our previous house, which we had for 29 years, it originally had a standard system with cold header tank, CH header tank, HW cylinder and all gravity feed except the kitchen cold (off the mains).
Initially I fitted a booster pump for the shower but the noise was horrendous.
Then I fitted a combi and made the whole house mains (the pressure was about 3 bar) but the shower was so-so and the bath took 20 minutes to fill (was a fairly large bath).
Finally I changed to a mains pressure hot water cylinder which did brilliantly for the last 10 years before we moved home.

In our current home (nearly 3 years now) I was going to have the same system, but the laws have changed and pressure vessel type regulations are now in force (controlled installation, inspection every year). So I've gone for the 'inside-out' option of a thermal store instead.
That's been a mixed bag. It works well for showers but loses its oomph after a few minutes when using bath fill flow rates, so I have to back the traps off a bit. Still fills a bath in 5-6 minutes though.
You also have to watch your timings as the 'tank' is shared with the CH - it needs a more sophisticated control system than I installed, but that's hindsight. I might improve it one day, but I kludge it with the timeswitch settings.
(I have a PDF of the system diagram if anyone is interested.)

This house is also in a hard water area with 6 bar mains, which is a bit mad - the cold system was always all mains and the noise from toilet cisterns refilling was dreadful (you had to pause the TV while it happened). So I've also fitted a water softener and a bunch of pressure reduction valves (down to 2-3 bar) and it's all pretty good now.

 

[MikeSh]

Well, my "Worcester" is actually a Bosch, so work that one out.

Yes. IIRC Worcester were one of the UK companies that gave combis a bad name here. I imagine Bosch will have sorted them out, but it's going on two decades since I was in the HVAC industry, so I can't honestly speak for here and now.
I've used Vaillant for the three boilers I've had (the combi and two system boilers) and never had a problem due to the boiler itself. (I thought I had once when water peed out of one, but it turned out to be a piece of crud from the system caught in the automatic air vent of the built-in system pump).

 

[EEPhil]

The "feeder tank" you describe is the header tank

I'm sure I knew that. Another senior moment when I forgot the correct term.

Your lot sound like a real bunch of cowboys. I protect myself by knowing at least as much as they do, or asking questions until I do.

I thought so too. I'll refrain from naming them. Chances are they only deal with housing associations etc. But as I said, as a tenant you don't get a choice. Don't let the £^&&$*s in and you get threatened with an injunction!

If you get any trouble from the boiler, your first port of call is to check the pressure gauge and top up if necessary. If you find yourself topping up more than reasonable, suspect a leak in the heat exchanger.

That's what I did. I don't think the installers refilled the system properly before spending half an hour outside chewing the fat before leaving. "Doing the paperwork" was the excuse. That's paperwork out of a plastic drinks bottle. Pressure now between 1.9 bar cold and 2.3 bar hot - so is within range. I'm keeping my eye on it as best I can.

The cowboys made it difficult to open the front panel - there is a pipe in front restricting the movement .
If regular topping up is required it's back to the landlord to report a repair!
FWIW The system the cowboys fitted was a Vaillant ecoTEC plus. As a reminder, if there's a fault a spanner appears on the display. Reminder to call in the bunch of spanners to repair the system.

 

[EEPhil]

An old-fashioned (but well insulated) hot cylinder is the way to go

I managed to con them into leaving that in. Keeps the airing cupboard warmish as well.