NEW BOILER SIZE:

[doitall]

bengasman wrote:

Second that. Have yet to get a client with less than 100% satisfaction.

How many plate HX have you changed in the last 5 years, or are they better now

[bengasman]

doitall wrote:

bengasman wrote: Second that. Have yet to get a client with less than 100% satisfaction. How many plate HX have you changed in the last 5 years, or are they better now

Bar 2 exceptions, I have only installed greenstar he + mk2, cdi mk1, and cdi mk2. Had 1 boiler with fried display (due to pulse or lightning according to wb bloke that fixed it foc) and broken lever on diverter, that is all the damage. Never been called out for hex from someone else's install either.

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[doitall]

Changed at least 10 that had pin holed. and it seems to be quite a common problem.

[bengasman]

So I heard. Odd, never seen one.
I wonder if it has something to do with how clean the system is.

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[Gasman77]

Installed 80-90 WB over the last three years with not one warranty call yet.... Also did a year as a wb engineer and I haven't changed a pin-holed heat ex yet. like I said, installed 2 Avantas, first one lasted an hour, second came with bits missing

HQ were less than helpful to be honest.

Maybe i was just unlucky

[doitall]

Pretty sure the pin holing plates are something to do with domestic water quality/type so could well be regional.

[RONCHAM]

Hi bengasman, thanks for your input. I meant "regular" boiler as per WB brochure ie not a system or combi boiler. I think the model number 24Ri, 18Ri etc. defines type.

I don't think boiler sizing is an exact science as they always add 10-20% for luck anyway after extensive calculations! But I'm fairly sure 24kw would be overkill and that 15 or 18kw is more than adequate.

My present boiler IS actually working (Ideal RS460) but from previous advice it seems to be possibly close on 20 years old and on borrowed time. On the other hand, I'm told they were made to industrial/commercial spec. back then and tough as old boots.

At risk of raking old ground, I'm also told my system was done on the cheap (with single MV on CH). But I was surprised to find tap stats are £70-80 which is dearer than an extra MV plus normal cylinder stat.

[kevplumb]

baxi 105 was known to do it in the north

partscentre where knocking them out at £30 +

which says it all really

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[doitall]

Did you get my email kev

[bengasman]

RONCHAM wrote:

I don't think boiler sizing is an exact science

It most certainly is not. If nothing else, depending on conditions most rads will dissipate between 10% more and 30% less than the figure given in the tables

RONCHAM wrote:

15 or 18kw is more than adequate.

Like I said, add up the lenght of all the radiator panels and you will get the output in kiloWatts.

RONCHAM wrote:

My present boiler IS actually working (Ideal RS460) but from previous advice it seems to be possibly close on 20 years old and on borrowed time.

Those old lumps have pro's and cons. There is nothing in them, so little to go wrong, bit like a vw beetle. The performance is terrible, bit like a vw beetle.

RONCHAM wrote:

On the other hand, I'm told they were made to industrial/commercial spec.

It is purely due to simplicity.

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[bengasman]

doitall wrote:

Pretty sure the pin holing plates are something to do with domestic water quality/type so could well be regional.

If it rots through stainless steel, what will it do to me?

How did you come to the conclusion that it is in the domestic side and not in the system side?

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[RONCHAM]

Hi bengasman, that's a good approx. you gave on radiator output/boiler sizing. I checked against Stelrad figures and it gives their quoted outputs plus about 10% (which is probably a good thing?). And suggests my living room rads are giving out about 4kw (but I suspect less) against a calculated requirement of about 2.5kw.

I'd like to think I can change/upsize a rad if desirable and boiler has adequate capacity, even if it attracts accusations from Goldberg of fiddling!!

My Drayton TRVs are at least 10 years old and I'm wondering if I should use the opportunity when the system is drained to get them changed as a matter of course??

[Agile]

If they are TRV 4 then they seem very reliable and I would not bother to change them.

Think carefull about what you will achieve by changing rads.

I have not read all but you seem to be sayingthe room needs 2.5 kW but you already have 4 kW of rads ???

Tony

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[RONCHAM]

Thanks Agile.

Main task is a new boiler and upgrading controls. I'm quite happy to keep exisiting rads (provided they don't leak with all the new power surging thru them!). Just thought, for completeness, might be a good time to change TRVs - would obviously be cheaper whilst guys are on site and system is empty, although still a few hundred pounds.

[Agile]

RONCHAM wrote:

Thanks Agile. Main task is a new boiler and upgrading controls. I'm quite happy to keep exisiting rads (provided they don't leak with all the new power surging thru them!). Just thought, for completeness, might be a good time to change TRVs - would obviously be cheaper whilst guys are on site and system is empty, although still a few hundred pounds.

We charge £35 eact to fit TRV 4s to an existing system if replacing the boiler.

Otherwise £60 to drain and refill plus £35 each for fitting TRVs to an existing system.

We dont do any work above cream colour carpets!

Tony

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