Large house combi v system boiler?

The store will never hit 10c because to do so the user would have to have been running lukewarm water out of his hot water taps for the last 20 mins.

Acttally that's not strictly true.
A 100kw phe will easily drop a 20L/min secondary side flowrate 60C in temperature on the primary side.
It would depend on the boiler size of course (and how the re-heat stats are set up) as to the proportion of the store that actually drops to 10 C.
 
Depending on the bank and HE maybe. To be honest I was just poking WS to see if he would bite but I think it got a bit technical for him.

Now fox hunting, badger baiting and dog fighting are all banned it's one of the few sports left.
 
Well, I could hardly contain myself during the continuing bedroom painting tonight, but 121 messages - I apologise for sidetracking you all!!

DP (I am north of Aberdeen, wrong direction for Stoney) et al, you have certainly been of assistance, many thanks.

Bucket has been wielded. However I only managed to get a piffless 7-8 litres per minute at the kitchen (nearest the supply). However when I ran about the house, switched on other taps, I still got 7-8 l/min. Which suggests to me that I am being rate limited by the pipe diameter (I believe that you should sum all of the supplies to get the actual rate?)? Am I delusional? Am I correct in thinking that I am supposed to be "guaranteed" 9 l/min??

Funniest of all was when I tried the bath, which is the furthest away of all taps from the inlet. It just about blew my 1 litre container away, filled it and more in less than 3 seconds. Which makes me suspect that this is coming direct from the loft and that is hydrostatic head that is giving me that benefit at the bath. The system I currently have is very complex (I could take photos, it's like the spaghetti junction of joinery), Jack was involved at several stages during the building of this house, I am finding funnies all over the place (wiring, TV aerials, plumbing obviously, joinery etc.....).

My original plan was to get all of the plumbing ripped out and start from scratch, hence my desire to get it right. This hasn't changed, however I suspect that without tracing the pipes I am at a bit of a loss. Which due to house geometry isn't going to happen....

This might kill this thread - after this post I wouldn't blame you - however thanks to you all for your useful (and lively and amusing at times!) comments.

Wish me luck....
 
Worse than children you lot!
I bet the OP must be having a nervous breakdown by
now!

I should think so. The thought of having an unvented cylinder bomb in your house is enough to send the man mad.
 
Holy moly, change of assessment.

After running around the ground floor (upstairs was just too much to handle), starting with all 6 cold water taps on (including round the corners on foot it's about 40 yards to the furthest outlets) I got about 4.2 l/min at the kitchen.

Switching off the cold taps sequentially the kitchen rate rose each time until I got back to the 7-8 litres/min. So I reckon that's put paid to my earlier loft tank nonsense and they are all in fact off the same supply.

And I conclude that the kitchen tap rate is limited by pipework / valving, and the mains rate here is above the 20 l/min quoted earlier, from several of the other taps (including bath). Does this sound reasonable? Feels like there's a PhD in here somewhere.

I'm beginning to rant to myself now. Kids think I'm mad.

ps all that graduate thing not all it's cracked up to be...
 
It would be foolish to offer 'educated' advice as I
have not visited your property (unlike some on this
site). So i would like to offer you some food for
thought. WB Highflow 440 or a good unvented system,
why not? But, I have worked on a large property in
the past and fitted 2 combi's, 1 for the upstairs and
1 for the downstairs, both on their own programmers,
making quite a versatile set-up.

Very good.

My own WB 37CDI
manages well in a 1925, 4 bedroom, 2 showers and 1
bath. 2 adults & 3 kids.

There you go. A Glow Worm 38 CX1 should do too. But get an Ethos 54KW and hey presto!
 
Do as one wise person as already said, get 3 or 4
people round to give you advice and quotes, then make
your decisions After all you may be stuck with it for
the next 10 years!

Quite ;)

Nope. Find out what you need and get them to quote. A combi.
 
You don't even know your own product you're trying to
recommend?!? The store will never hit 10c because to
do so the user would have to have been running
lukewarm water out of his hot water taps for the last
20 mins.

Stop guessing. A plate heat exchanger is 90% plus efficient in thermal transfer. Together with a modulating DHW pump temps of 10 to 20C are returned.

Perhaps that's what heat bank customers do - think "I
need some water at 10c, I'll just switch the hot tap
on and wait for the water to cool".

After me explaining to you. You really are dumb! Still to tiling the bathrooms.

Then you go and say "LARGE BOILERS CAN BE USED
WITHOUT ADVERSE EFFECTS".

That is with a heat bank. Do you how they work?

If I wanted a large boiler
I'd get a highflow combi.
Thanks for a completely
useless benefit, like most
of the others.

You really haven't a clue what all this is about!! :) Pathetic!

< snip babble & tripe >
 
Depending on the bank and HE maybe. To be honest I
was just poking WS to see if he would bite but I
think it got a bit technical for him.

Stop digging yourself in a hole. You didn't know! Haven't a clue at best.
 
My dearest WS, I have probably forgotten in one day what it would take you a lifetime to learn. If you'd like an in-depth discussion of fluid dynamics and particle energy transference please let's begin a new thread.

I'd love to keep digging old boy but I fear there's not enough room for us both. If you desire to dramatically increase the sales and installations of heat banks I'd strongly suggest that you follow an appropriate course of positive action, namely to STFU!
 
My dearest WS, I have probably forgotten in one day
what it would take you a lifetime to learn.

Oh No!!! He came out with that one. I thought he was going to come out with, "I have been doing this for 20 years". Translation..."I have 6 moths experience and repeated it 40 times".

If you'd
like an in-depth discussion of fluid dynamics and
particle energy transference please let's begin a new
thread.

No point as you don't know much about it. That is clear. Just read what I wrote for starters and understand that.

< snip tripe >

Sad. I know.
 
My dearest WS, I have probably forgotten in one
day what it would take you a lifetime to learn.

Oh No!!! He came out with that one.

Sorry, have I said that to you before - I don't remember. But you do ;)

(Even Oscar would be proud of that one)

* They say never judge a book by it's cover. Though I found "5ex nymphos in Amsterdam" to be highly accurate *
 
Walter Systems.
Resident Plonker,
Plumbers Forum,
Screwfix Talk,
Screwfix.com.


Please mark all correspondence:

" Danger: Unexploded UV Cylinder
 
Well, as said 'Naesure' with combi's there are pros
&
cons.
Combi's are sized on there HW output & most of the
larger condensing combi's require high gas pressure
&
flow rate at the appliance, which may result in a
meter change & up too 35MM as service
pipe...etc..etc.

I know no domestic combi that requires a U16 meter.
Only if you keep gas fires and other unnecessary
y stuff will that result.

Oh yes, Naesure will never need a gas cooker, fire or BBQ. He has already said he likes to cook, so a big 6 ring cooker is sure to be on his wish list........Water System you're an arzehole, stop digging now!!


But really for a larger domestic installation like
yours, storing hot water is the optimum system and
with the incoming mains pressure/flow permitting,
an
unvented cylinder will give your good pressure &
simaltainious use of appliances.

But expensive!! And big!!!! And large combis store
water to!! Try looking at a high flow Rinnai
multi-point that can be fitted outside.

Oh ye, he can fit a 54KW combi as you recommended & get a gas supply piped directly from the North Sea!!

How many people does it take, telling you you're talking *, before you shut up!!

You clearly have mental health problems, as I & others have pointed out before.

[Edited by: admin]
 
The store will never hit 10c because to do so the
user would have to have been running lukewarm water
out of his hot water taps for the last 20 mins.

Acttally that's not strictly true.
A 100kw phe will easily drop
a 20L/min secondary side flowrate
60C in temperature on the primary
side.

Yep. Even less than 20 litres/min using a modulating DHW pump, pumping through he plate heat X will give 10C out of the plate heat X back to the bottom of the store.

It would depend on the boiler
size of course (and how the
re-heat stats are set up) as to the
proportion of the store that actually
drops to 10 C.

The boiler size?

Well usually the bottom 1/3. That is very efficient boiler condensing operation for around 1/3 of the reheat of the store of water. Using thermal layering and heating the cylinder top down, the hot water will work its way down the cylinder in a distinct line. 70C can be felt at the top and 10C at the bottom. Having a store set to 70C will ensure approx 90% of the reheat will be in condensing mode and 1/2 at least, of reheat in highly efficient condensing operation as the return temperature is way below 30C. Even if the store is set to 82C, at least 80% of reheat is condensing operation. The dumb ones think, "oh 80C can't condense!", not understanding basic thermal layering, which is inexcusable for people dealing in water heating.

Some stores have a deliberate cool section at the bottom, as does the ACV HeatMaster. It does this by having a stainless steel coil at the bottom of the store, that preheats the cold mains water. But, modulating the DHW pump through the plate heat X will do just then same.

Having the rads sized for 20C across the flow and return, and using a weather compensator, will ensure very low CH return temperatures when using an integrated heat bank thermal store. Set the compensator to control the return temperatures, not the flow temperatures. Typically temperatures below 30C will be returned (50C flow), which extract 80% of the latent heat from the flue gasses.

All simple to do. Cranfield University sated that thermal storage is 15% more efficient that other forms of heating and DHW.
 
Are you OK Nasure?? It's no surprise you are getting confused!!
To check your incoming water mains, just check the kitchen sink cold tap, whilst running your outside garden tap. That will give you a fairly good guide as to your incoming main water dynamic flow rate. The pressure would also be better checked, which you will need a gauge to check.

To be fair, Water Systems is knowledgeable and does get a lot of stick on here, as he thinks every Plumber is thick & most of his suggestions are far from pragmatic. Don't get me wrong, we Plumbers are very conservative, but we stake our reputations on things that work & people being happy.

We come across guys like him quite a lot, mainly working for manufacturers, stuck in some back office hardly seeing the light of day and little or no contact with the outside world...........I'm sure you know the type, sad wee men with their nose in a book, void of any social skills.
 
To be fair, Water Systems is knowledgeable and does
get a lot of stick on here, as he thinks every
Plumber is thick & most of his suggestions are far
from pragmatic.

"far from pragmatic"!!!!! What is more simple than a combi?

Todger, you have been on the whiskey again!!!

void of any social skills.

Todger, now you were not nice to the Manchester police! Highly unsocial of you! No social skills whatsoever when tredding golden English soil.

Todger, keep ripping the floorboards up. Suits you.
 
Oh ye, he can fit a 54KW combi
as you recommended &
get a gas supply piped directly
from the North Sea!!

Todger, a domestic gas meter will give you 62kW. Now you know.

Todger, you are unable to grasp anything you have not done repetitively for 10 years. Anything new? Forget it.
 
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