On Wed, 22 Jun 2005 22:19:15 +0100, Ed Sirett
wrote:

On Tue, 21 Jun 2005 21:14:29 +0000, Martin Evans wrote:



o plumber 2 (who spent a considerable amount of time with me - what
patience) suggested going to a combi boiler (although he would fit a
conventional one) - in fact a Worcester Greenstar 440 floor standing
combi boiler. He said

I Maybe wrong but IIRC all Greenstar boilers are condensing.

Sorry, I meant to say he would fit a condensing boiler with my
conventional hot water store system as opposed to a combi system.

a) at 20l/min at 35 degrees C rise, running on mains pressure (subject
to testing mains pressure which I'm given to believe is good) it was
more than sufficient to match my existing pumped shower and everything
else.

Initially before the store of HW in the boiler gives out this is likely
true. The usability of the system is likely to be good enough except for
high speed bath running.

Well, what do I know (which I why I posted here). What I did take some
confidence from is that the boiler he recommended was not small and
did seem to be the higher end of the hot water producing rates of the
boilers I'd looked at. I sort of thought if this (higher end) boiler
didn't do the trick someone would have noticed/complained and I'd have
been able to find this out on the net.

(Wary of potential jokes) we don't bath that often - the shower is the
main thing. If the bath takes a little longer to fill so be it. Even
with a stored hot water system, the filling of a bath needs attention
to make sure it is not getting too hot or cold.


b) it would be cheaper to install than keeping my existing system as
it was far less components and mostly required ripping (bypassing)
existing system out rather than renewing/replacing. Basically, the
cold water tank would be bypassed, the cylinder goes, my shower pump
goes, electrics are trivial since all that is needed it something to
the boiler. I liked the sound of losing my shower pump IF the output
at the shower head was as good since the shower pump is noisy.

A wall stat (preferrably programmable) will also be needed to comply with
current regs.

From youomments a programmable wall stat seems the way to go - I will
make sure this is in the spec and that the TRV currently in the hall
radiator also goes.


c) my gas supply to boiler was 15mm and needed to be 22mm. There is no
easy way to get a 22mm pipe from the 22mm pipe at the back of my meter
to the boiler but it could be run outside (around a 3m run) so long as
the pipe was held off the wall.
And properly sleeved etc. etc. All true.

There was no menion of sleeving but given the thoroughness of plumber
1 I am assumig this was a detail he just didn' give rather than one he
wasn't going to do - but now aware of it I'm all the wiser.


d) To check the new system would cope/match my existing shower pump I
needed to lookup the output from my pump (i've struggles with this as
the plate on it quote 3 l/min numbers). Also, I needed to check the
spec of the shower valve in my ensuite to ensure it was OK for the new
increased standing pressure.
These are not the end of the world to replace later if they are
unsatisfactory.

I am probably pushing it here but I've tried (jn vain) to find out if
this valve is up to it. I can't find anything in the accompanying
literature which helps (perhaps I've lost it - but I doubt it). What I
know is that it is from the Hansgrohe talis range, fitted about 5
years ago and that my pump delivers (I think - see previous comments)
around 9l/min ( I could post all the numbers on the existing pump).
Interestingly, plumber 2 who has now provided a quote has specifically
said the Miras shower valve I have on another gravity fed shower is OK
and specifically said they don't know about my ensuite hansgrohe valve
(so if it needs replacing I'd have to pay the costs).


e) we discussed pluming etc and the flue would be routed outside and
up the wall to above head height. (=2m).

That avoids the need for a terminal guard but no word on the possible
pluming problems and air-space wars.

Argh neighbours. As I think I said, there is around 3 ft to a 6ft high
fence and then another 3ft to my neighbours house wall. She is coming
up to 80 and frets about everything (as I suspect everyone coming up
to 80 does). In fact she rang the doorbell tonight asking me to look
at her boiler because she was worried it was going to explode because
she'd turned her heating off and her upstairs radiators were getting
warm. I don' think there'll be any real issue her but I would not want
her walking past whilst some hot geyser shot out - she'd think it was
wrong/broken/angerous and would want reassuring.



f) we discussed reliability of Worcester 440 and he said he had fitted
loads, it was good, needed to be serviced once a year and although
slightly more involved than a conventional boiler was not time
consuming or expensive. On board diagnostics would even detect a leak
in my heating system.

Fair comment.


g) Mentioning some pipework in concrete floor he was unperturbed,
suggesting the increased pressure of my new sealed system was not that
high and if existing system was working I'd be OK.

See my previous post, however a positive attitude has much to commend it.

That's what I thought - I definitely had a better feeling about this
guy.

h) I mentioned past experience of combi boilers (over 12 years ago) and
he said the worcester 440 was miles ahead of whatever I had then and I
would not suffer from excessive reduced flow in winter. He did go on
quite a bit about what temperature my shower ran at and how I was mixing
alot of cold water with hot to get confortable.

Fair comment. This boiler has good performance at the expense of floor
space, size and weight.

Floor space, size and weight are not really a factor - I've got plenty
of space, and a concrete floor and all I have to contend with is my
wife's possible complaints that she's not got as much space as she
would have liked. That is minimal compared with the shower isn't as
good.



i) he said my existing cylinder (although only 5 years old) was not up
to spec since it did not have 2" of insulation (I might have the exact
number wrong).

Possibly true.

You may be able to detect I'm starting to favour plumber 1 by now but
plumber 2 did not mention this at all and now his quote came in it
included rotating the cylinder through 90 degress for easier access
rather than because it was not up to spec.



j) all (optional but included in his price) would be in the boiler
itself except for a room thermostat. He pointed out the problem with
having a room thermstat in the hall where the radiator had a TRV.

The TRV must go. As discussed.

I've now got the message - thanks.


k) the worcester 440 had an in built 12l (I think) vessel which had some
advantage in the speed in which hot water reached my taps - not sure
exactly.

See 'f' and 'a' and 'h'


Cost £2600 (for combi boiler worcester 440 floor standing boiler,
replacement gas supply to boiler, ripping out / bypassing old system) -
sealed system.

Probably about right.

Plumber 2 came in with 2 quotes for keeping my existing system
(upgrading to specs) or going to a combi. Prices we

£1788 for drain down system, disconnect boiler and remove from site
and dispose of same,. Supply and fit worcester 28HE condensing boiler
which would eliminate any problems with air in system, It also allows
to retian existing hot water storage system cylinder but we would have
to turn this to allow better access to pipes and to motorised valve.
Cap off heating tank and remove same. Connect new boiler to existing
central heating pipes. Supply and install new twin channel digital
programmer complete with optimising room temperature control. Carry
out all necessary electrical work to boiler and controls, including
any necessary bonding to work we arried out. Refill system, drain and
flush with BC10 fluid. Refill with addition of inhibitor and
commission new boiler, carrying out necessary gas tests. Fill in
Benchmark logbook and submit Corgi Notification as required under
current regulations. Test the above and leave in full working order.

Sorry, I' getting cynical perhaps but I really liked the "Test the
above and leave in full working order" - I'd enjoy paying for that -
which surely the job would not be complete without.

quote 2 was basically to convert to a combi Bosch Greenstar 35CDI and
required work - specific exclusions for the Hansgrohe shower valve
which may not be up to the job - I don't like this as I'd expect that
a plumber could confirm (or get confirmed) whether this shower valve
was up to the job instead of saying it may/may_not_be and it is up to
me to sort it out - I'm paying for the work and I'm not the expert -
surely it is part of the expertise of the plumber (you are paying for)
to spot this and satisfy themselves. If plumber looked at it and said
it was not up to the job them it could be added to the quote but
leaving it to me to decide when I don't know does not seem good
enough. Cost £2380. Quote gives the possibility of upgrading to
greenstar 40cdi at an extra of £200 + VAT without any recommendation -
why? On what basis am I supposed to decide whether the 35CDI or the
40CDI is the right choice - here again - I'm not the expert and that
is why I've called a plumber - if there are choices I'd expect some
info to help me to decide.

There were 2 exclusions (fair enough except I'd not receive any
advice) but on top of the quote was "flushing the system to get rid of
sludge/debris which may have accumulated in the system over time and
that could affect the performance of the new boiler" and "You do not
have to have this done but it is possible that you may encounter
problems with the manufacturers waranty should the bolier fail due to
its operating on a dirty system, As installers therefore, we have to
recommend that the system is flushed thorouhly before a new boiler is
installled." . "jet flush of your central heating system would be
£330.00 plus vat".

Scare tactics?



o plumber number 2

quote not received yet but it was for a wall mounting Worcester 3XX
(something) 12l/min output at X degrees C rise (have not got the
brochure).

See quote above.

o concurred with plumber 1 than cylinder was not up to spec. Also said
the hot water feed to my shower pump was too high in the cylinder. Also
said the cylninder would be better turned through 90 degrees for easier
access to valve - fair enough.

o concurred with plumber 1 re TRV and room therm in same room.

o on business of 22mm gas feed to boiler - some needed it some don't -
often plumbers size up from 15 to 22 - a bit wishy washy - I was not
certain what was required but if a 22mm pipe was required as with
plumber 1 it could be run along outside wall.

o on combi boilers he would do a quote for both but a combi would be
more expensive since it required ripping out a lot of stuff - somewhat
at odds with plumber 1 who said the exact opposite.

o as with plumber 1 he'd need specs for ensuite shower valve as it might
not be up to increased standing pressure if we went combi boiler but the
myra shower valve in bathroom was certainly OK (I knew this anyway as
some tosser who previously installed shower in bathromm before we moved
here plumbed it in to the bath supply where the cold water was mains
pressure). When it leaked badly I needed to replace it in a hurry and
found I needed a more expensive valve to handle the imbalance. Since
then it has been replumbed to the cold tank.

o on combi boilers and my concern over loss of output in winter and at
my main ensuite shower he said it would cope so long as someone did not
use any water elsewhere in the house (whether cold or hot). He
recommended not having a combi boiler.

o servicing required for worcester 3XX was once every 12 to 18 months
and would cost around £50.

o room thermostat was required and they would not need to put cables in
as it was a (cableless) radio one.

o would quote for a powerflush at £395 which would take the best part
of a day as it involved connecting to heating system and flushing
through plus connecting to each radiator individually. When I suggested
this sounded alot (BG quoted £200) he said if the system had been
drained recently and was clean I could just ignore that in the quote.
They would have to drain the system twice anyway and lfush it with some
agent. He didn't try to sell it to me especially when I said the system
had been drained more than 5 times in the last 2 years alone and drained
out clean (also all of my radiators except one is brand new).

Someone who having got a powerflush gadget actually wishes to used only
when needed, a rare event, a mark of honesty perhaps?

and at £330 + VAT and the comment that this would take nearly all day
made me go off this guy.

o mains pressure was good in my area and not a worry.

o it cost them £5 to register the installation with Corgi who would
send me something I needed to keep as it would be required when I sold
my house.

Actually £4 by phone and £2.50 online. Hardly worth itemising really.
As to whether you _really_ will need it when you sell - who knows.
It is a legal requirement to register the exchange of a heating appliance
with building control it is done with this.

In this increasinglly nanny state I can imagine having the
documentation for this kind of work will be necessary. I cast my mind
back to when we bought this house and after we did I very seriously
thought about suing the surveyor who did not pick up some substantial
faults we could have used as a bargaining chip which have cost us big
bucks since.


o gas mains was being updated in my area since it fell off too much (and
caused some boilers to shut down) early in the morning when all these
new condensing boilers switched on.

Some condensors are quite sensitive to under-pressure others are very
tolerant. Condensors use no more gas and possibly less than
non-condensors. Combis tend to place bigger peak
demands on the supply network. However if the mains are being fixed in
your area what's the problem?

Probablty none and that is a good thing - plus point for local
plumbers
..

What I think is a summary of the "true" bits of advice/information I
received from BG, local plumbers and this news group a

o you have to fit a condensing boiller unless you can amass 1000 pts on
a rather difficult to achieve scale. Certainly, a replacement boiler is
unlikey to achieve 1000 pts.
Yep


o plumning - I'm not going there - it seems a contentious issue.


o when moving to a condensing boiler you need a fully pumped system (no
gravity fed hot water) - this is law.

Yep

o don't have TRV on the radiator in the same room as a room thermostat -
also avoid rooms with other heat sources - kitchen, rooms with fires etc
Ed.
Just to be clear . TRVs are needed nearly everywhere. The roomstat is
needed somewhere but not with the TRV - in the hall is a good place.
remove existing TRV if needed.



o condensing boilers produce condensate which is slightly acidic and has
to have somewhere to drain away.
Yep


o some boilers come with bypass valves, some don't. You can't go all
TRVs without a bypass valve.

If the boiler says it needs a bypass you must have one TRVs or not.

Poimt taken - I was not clear enough.


o You need a "boiler interlock" that completely turns off the boiler
when the house is hot. Normally this is supplied by the room thermostat.
If there is none, another method must be used, such as a flow switch on
the heating circuit - thanks Christian/Andy/John.
Yep, but go for the room stat. The alternative gear will not be cheaper,
people will be less familiar with it. A programmble room stat can provided
an accessible heating control.

My fault for not taking the point you made earlier - I will be
following this up.

o some condensing boilers are modulating so instead of a constant power
output they adjust to conditions. Minimum outout of boiler is worht
looking at.

I don't think you'll find any fixed power modern boilers condensing or not.
The lower minimum the better. Provided the HW heating is OK (combi).
If you co for a cylinder then I suggest calculating the heating
requirements and then selecting the right sized boiler again lloking at
the minimum.

o There should be electrical bonding from the meter to the main earthing
point in the house. The service bonding ought to be done on the consumer
side of the meter rather than the supply as used to be the case.
Yep


o water cylinders are subject to building regs and upgrading a system
might (or must) mean upgrading the cylinder to current regs. Also, see
fast recovery cylinders (this was not mentioned to me by anyone
quoting).
A compliant cylinder is a fast(ish) cylinder.

If I go combi this would be irrelevant,


Both plumbers seem to be saying the right sort of things give or take a
few details. The second one wishes to fit a cheaper lighter simpler combi
with much less HW output. Still good for shower (but probably not as good
as what you have with a pump).

I don't like hedgeing my bets. Ok, since posting the numbers are
interesting since the keep my exisitng system but upgrade my boiler
comes in at £1788 but then dd powerflush ( £330 + VAT) and £200
uograde to biigger boiler and plumber 1 is looking quite attractiive.

If the wiring from the hall to the boiler is awkward then the £50 extra
for a wireless room stat could be worth the extra.

It is not that awkward. I replsaered hall and put in 25mm conduit
which it would be easy to pull though unlike previous system which was
so tiht there was no chance off pulling through new cable.

Thanksagain for the help and advice.

Martin
--
Martin J. Evans
Wetherby, UK